Power transmission and distribution facility

Abstract

To provide a power transmission and distribution facility which improves work efficiency in assembling a case metal fitting and a cover fastening nut when a cover is attached to a case of the power transmission and distribution facility.SOLUTION: A power transmission and distribution facility includes a case (11) that houses a power transmission and distribution component, a cover (12) that detachably closes an opening (111) provided in the case, a case fitting (3) that is provided on an outer peripheral surface of the case, a holding fitting (2) that engages with the case fitting and holds the cover, a fastening bolt (4) that is inserted into a through hole (211) formed in the holding fitting, and a cover-fastening nut (5) that is disposed in the case fitting and fits onto the fastening bolt. 321, A rotation allowing part 322 for allowing rotation of the cover fastening nut in a state that the cover fastening nut is fitted to the fastening bolt is formed above the posture regulating part.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to power transmission and distribution facilities. [Background technology]

[0002] Conventionally, transformers that have a coil and an iron core housed in a case and are mounted on a pole are widely known. In such transformers, the core part including the coil and the iron core is fixed to the case by bolting via a cover member (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-196759 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the pole-mounted transformer of Patent Document 1, no consideration is given to improving the work efficiency when assembling the case metal fittings and the cover tightening nuts when attaching the cover to the case.

[0005] The present invention has been made in consideration of the above circumstances, and provides a power transmission and distribution facility that can improve work efficiency when assembling case fittings and cover tightening nuts when attaching a cover to the case of the power transmission and distribution facility. [Means for solving the problem]

[0006] The power transmission and distribution equipment of the present invention is a power transmission and distribution equipment comprising a case for storing power transmission and distribution components, a cover that can be attached and detached to cover an opening provided in the case, case metal fittings provided on the outer surface of the case, clamping metal fittings that engage with the case metal fittings to hold the cover in place, a tightening bolt that is inserted into a through hole formed in the clamping metal fitting, and a cover tightening nut that is disposed on the case metal fittings and engages with the tightening bolt, wherein the case metal fittings include an attitude regulating portion that regulates the attitude of the cover tightening nut so that the axial direction of the threaded portion in the cover tightening nut is directed toward the through hole, and above the attitude regulating portion is formed a rotation allowing portion that allows rotation of the cover tightening nut when the cover tightening nut is engaged with the tightening bolt.

[0007] In this aspect, the power transmission and distribution equipment includes a case that houses power transmission and distribution components and a cover that detachably closes an opening formed in the top of the case. The case and cover are fastened and fixed together by a clamp pressing from above the cover. A clamping bolt inserted into a through hole formed in the L-shaped clamp is threadedly engaged with a cover clamping nut placed on a case metal fitting attached to the outer circumferential surface of the case. This reduces the distance between the head of the clamping bolt and the cover clamping nut, and the clamp presses the cover from above against the peripheral end surface that defines the opening of the case, allowing the cover to close the opening and seal the case. The case metal fitting attached to the outer circumferential surface of the case includes a position restricting portion that restricts the position of the cover clamping nut and a rotation permitting portion that permits rotation of the cover clamping nut. The position restricting portion restricts the position of the cover clamping nut so that the axial direction of the threaded portion of the cover clamping nut faces the through hole when the cover clamping nut is placed on the case metal fitting. During the manufacturing stage of power transmission and distribution equipment, after the process of placing the cover clamping nut on the case metal fitting, the process of engaging (threading) the clamping bolt into the cover clamping nut and tightening it is performed. When the cover clamping nut is placed on the case metal fitting, the posture regulating unit regulates the posture of the cover clamping nut so that the axial direction of the threaded portion of the cover clamping nut faces the through-hole, i.e., so that the center of the through-hole is located at the extension of the central axis of the screw hole in the cover clamping nut. Therefore, when the cover clamping nut is placed on the case metal fitting, the through-hole of the clamping metal fitting and the screw hole of the cover clamping nut are aligned on the same line, allowing the clamping bolt inserted through the through-hole of the clamping metal fitting to be efficiently engaged with and tightened into the screw hole of the cover clamping nut. Because the case metal fitting functions as the posture regulating unit in this way, posture adjustment work, such as moving or rotating the cover clamping nut to align it, is unnecessary when placing the cover clamping nut on the case metal fitting, improving the work efficiency when assembling the case metal fitting and the cover clamping nut. Furthermore, a rotation permitting portion is formed above the position restricting portion, and the rotation permitting portion permits rotation of the cover fastening nut when the cover fastening nut is engaged with the fastening bolt.Even when the cover clamping nut is engaged with the clamping bolt, loosening the cover clamping nut increases the distance between the head of the clamping bolt and the cover clamping nut. This releases the cover from being pressed against the case by the clamping metal fittings, allowing the cover to be removed from the case, making the case and cover detachable. Even when the cover clamping nut and the clamping bolt are loosened and engaged (loosely engaged state), the cover clamping nut remains positioned on the case fittings. In this case, by pulling the cover clamping nut and the clamping bolt, which are in a loosely engaged state, upward and positioning the cover clamping nut in the rotation permitting portion above the position restricting portion, the cover clamping nut can be rotated in the rotation permitting portion. When the cover clamping nut and the clamping bolt are tightened and engaged (tightly engaged state) when pressing the cover against the case, the axial direction of the clamping bolt is vertical. Then, by rotating the cover clamping nut and clamping bolt, which are in a loosely fitted state, around a rotation axis perpendicular to the vertical direction, the retaining metal through which the clamping bolt is inserted can be moved to a position where it does not interfere with the cover, i.e., moved out of the area facing the top surface of the cover, thereby moving the cover that covers the opening of the case upward and removing the cover from the case.

[0008] In the power transmission and distribution equipment of the present invention, the case fittings include two protruding pieces along the circumferential direction on the outer peripheral surface of the case, and each of the protruding pieces has an insertion hole formed therein through which the cover tightening nut is inserted, and the posture regulating part is formed by a flat bottom surface on the inner surface forming the insertion hole, and the cover tightening nut has a flat lower surface, and the lower surface of the cover tightening nut is placed on the bottom surface of the posture regulating part, so that the posture regulating part regulates the posture of the cover tightening nut.

[0009] In this embodiment, a plurality of case metal fittings, for example, four, are provided at equal intervals along the circumferential direction on the outer peripheral surface of the case. The case metal fittings include two protruding pieces along the circumferential direction on the outer peripheral surface of the case. These two protruding pieces are formed, for example, by crank-shaped plate members and are provided at the same height on the outer peripheral surface of the case with their inner surfaces facing each other. The case metal fittings may have a central plate portion connecting the protruding ends of the two protruding pieces and be configured in a U-shape when viewed in cross section from above. Each of the protruding pieces constituting the case metal fittings has an insertion hole through which a cover clamping nut is inserted. The insertion hole is formed by the inner surface constituting the periphery of the insertion hole; in other words, the area surrounded by the inner surface corresponds to the insertion hole. The length of the cover clamping nut in the insertion direction when inserted into the insertion hole, i.e., the longitudinal length of the cover clamping nut, is equal to or greater than the distance (face-to-face distance) between the two opposing protruding pieces. Therefore, the cover clamping nut inserted into each of the insertion holes formed in the two protruding pieces rests on the bottom surface of the inner surface forming the insertion hole. In this case, the bottom surface forming the insertion hole is flat, and the lower surface of the cover clamping nut is also flat, thereby forming a position control portion. That is, when the cover clamping nut is inserted into the insertion hole, the flat lower surface of the cover clamping nut and the flat bottom surface of the insertion hole can be placed face-to-face and in surface contact, allowing the cover clamping nut to be placed on the bottom surface of the insertion hole in a stable position. The cover clamping nut has a threaded portion (screw hole) formed in it so that the axial direction of the threaded portion (the central axis direction of the threaded hole) of the cover clamping nut faces the through hole formed in the clamping metal fitting when the flat lower surface of the cover clamping nut and the flat bottom surface of the insertion hole are placed face-to-face and in surface contact. In this case, the screw hole of the cover tightening nut is formed through the upper and lower surfaces of the cover tightening nut, and the axial direction of the screw hole may be formed perpendicular to the lower surface.Therefore, when the cover clamping nut is placed on the case metal fitting, that is, by aligning the underside of the cover clamping nut with the lower part of the insertion hole (the bottom surface forming the insertion hole) and inserting it into the insertion hole, the posture of the cover clamping nut is regulated and stabilized, and the clamping bolt that has passed through the through hole of the retaining metal fitting can be efficiently engaged (screwed) with the cover clamping nut. The planar underside of the cover clamping nut and the planar bottom surface of the insertion hole are not limited to being a single plane, but may be composed of, for example, two V-shaped planes (multiple planes). In this case, the underside of the upper cover clamping nut may be convex, protruding downward, and the bottom surface forming the insertion hole may be concave, recessed downward.

[0010] In the power transmission and distribution equipment of the present invention, the rotation tolerance portion and the posture control portion are formed by the inner surface that forms the insertion hole, the rotation tolerance portion is formed wider than the posture control portion, and the cover tightening nut has a rectangular shape when viewed in cross section in the insertion direction relative to the insertion hole.

[0011] In this aspect, the insertion hole is formed by an inner surface that forms the periphery of the insertion hole. The rotation allowance portion and the position restriction portion are formed by the inner surface, and the insertion hole includes the rotation allowance portion and the position restriction portion. That is, the lower portion of the insertion hole functions as the position restriction portion, and the middle or upper portion of the insertion hole functions as the rotation allowance portion. The rotation allowance portion that forms part of the insertion hole is formed wider in the width direction (horizontal width direction) perpendicular to the insertion direction of the cover tightening nut than the position restriction portion that forms the rest of the insertion hole. That is, the width of the lowermost portion of the insertion hole (the bottom surface that forms the insertion hole) is smaller than the width of the insertion hole at the upper portion. In this case, the width of the insertion hole may gradually increase from the lower portion to the middle portion and gradually decrease from the middle portion to the upper portion, thereby forming an elongated hole extending in the width direction. That is, the lower and upper edges of the insertion hole may be linear, and the left and right side edges may be arc-shaped (semicircular). Alternatively, the lower and upper edges of the insertion hole may be linear, and the length of the lower edge may be shorter than the length of the upper edge, thereby forming the insertion hole in an inverted trapezoid shape. The cover clamping nut has a rectangular shape when viewed in cross section in the insertion direction of the insertion hole, and the width of the cover clamping nut (the width perpendicular to the insertion direction) is equal to or less than the width of the position restricting portion. Furthermore, the length of the diagonal line of the rectangular cover clamping nut when viewed in cross section is greater than the width of the position restricting portion and less than the width of the rotation permitting portion. Because the length of the diagonal line of the rectangular cover clamping nut is greater than the width of the position restricting portion, rotation of the cover clamping nut about the insertion direction can be suppressed when the cover clamping nut is positioned in the position restricting portion. Furthermore, since the length of the diagonal (diagonal of the rectangle) of the cover tightening nut is smaller than the width of the rotation allowance portion, when the cover tightening nut is positioned within the width of the rotation allowance portion, rotation of the cover tightening nut can be allowed around the insertion direction.

[0012] In the power transmission and distribution equipment of the present invention, the rotation tolerance portion and the posture control portion are formed by the inner surface that forms the insertion hole, the posture control portion is rectangular, the rotation tolerance portion is semicircular, and the cover tightening nut is semicircular when viewed in cross section in the insertion direction relative to the insertion hole.

[0013] In this aspect, the rotation permitting portion that forms part of the insertion hole is rectangular, and the position restricting portion that forms the other part of the insertion hole is semicircular. Because the rotation permitting portion is located above the position restricting portion, the insertion hole has a hole shape with a horizontally elongated rectangular bottom and a semicircular top. In this case, the width (longitudinal direction) of the rectangular position restricting portion may be the same as the width (diameter) of the semicircular rotation permitting portion. The cover clamping nut is formed as a rod body that is semicircular in a cross-sectional view in the insertion direction of the insertion hole, and has a flat bottom surface and a curved top surface. When the cover clamping nut is inserted into the insertion hole, the flat bottom surface of the cover clamping nut rests on the bottom surface of the rectangular position restricting portion. The rectangular position restricting portion has a flat bottom surface, allowing the bottom surface of the position restricting portion and the underside of the cover clamping nut to face each other and make surface contact, allowing the cover clamping nut to be placed on the bottom surface of the insertion hole in a stable position. The screw holes in the cover clamping nut are formed perpendicular to the flat bottom surface from the curved top surface. Therefore, the cover clamping nut can be placed on the case metal fitting with the axial direction of the screw holes facing the through-hole of the clamping metal fitting. Furthermore, when the cover clamping nut and the clamping bolt are loosely fitted (loosely fitted state), the cover clamping nut can be positioned in the semicircular rotation permitting portion. This allows the curved top surface of the cover clamping nut to be aligned with the rotation permitting portion, i.e., the inner surface (top surface) that forms the upper portion of the insertion hole, allowing the cover clamping nut and the clamping bolt in the loosely fitted state to rotate around a rotation axis perpendicular to the vertical direction.

[0014] In the power transmission and distribution equipment according to the present invention, the cover tightening nut has an engaging portion that engages with at least one of the protruding pieces when inserted into each of the insertion holes formed in the two protruding pieces.

[0015] In this aspect, the cover clamping nut has an engaging portion that engages with the protruding piece. When the cover clamping nut is inserted into the insertion hole of each of the two protruding pieces, the engaging portion engages with either one or both of the protruding pieces. The engaging portion provided on the cover clamping nut allows for positioning when the cover clamping nut is inserted into the insertion hole. This makes it possible to determine the insertion length of the cover clamping nut into each of the insertion holes of the two protruding pieces, improving work efficiency when assembling the case metal fitting and the cover clamping nut.

[0016] In the power transmission and distribution equipment according to the present invention, the engaging portion is configured by a convex portion provided on the lower surface of the cover tightening nut.

[0017] In this embodiment, the planar underside of the cover clamping nut has convex portions protruding downward from the underside at both ends in the insertion direction of the cover clamping nut, and these convex portions constitute engaging portions. The distance between the convex portions at both ends of the underside, i.e., the convex portion provided on one protruding piece side and the convex portion provided on the other protruding piece side, is equal to or greater than the distance between the two protruding pieces, so that the two protruding pieces are interposed between the two convex portions. For example, the distance between the two convex portions may be set between 1 and 1.2 times the distance between the two protruding pieces (protruding piece separation distance × 1 ≦ protruding piece separation distance ≦ protruding piece separation distance × 1.2). Providing convex portions on the underside of the cover clamping nut in this manner allows for positioning of the cover clamping nut when inserted into the insertion hole, improving the work efficiency when assembling the case metal fitting and the cover clamping nut.

[0018] In the power transmission and distribution equipment according to the present invention, the engaging portion is configured by a flange portion provided at an end of the cover tightening nut.

[0019] In this embodiment, the cover clamping nut has a rod-like shape and a flange portion is formed at the rear end of the cover clamping nut in the insertion direction. That is, the flange portion serves as an engagement portion by being positioned at the rearmost position when the cover clamping nut is inserted into the through hole. The flange portion is elliptical or disk-shaped, and the diameter (longer diameter in the case of an ellipse) of the flange portion is greater than the width of the through hole. Therefore, when the rod-like cover clamping nut is inserted into each of the insertion holes formed in the two protruding pieces, the rearmost flange portion abuts against the outer surfaces of the protruding pieces located around the insertion holes, thereby functioning as a stopper that prevents further insertion. Providing a flange portion at the end of the cover clamping nut in this manner allows for positioning of the cover clamping nut when inserted into the insertion holes, improving the work efficiency when assembling the case metal fitting and the cover clamping nut.

[0020] In the power transmission and distribution facility according to the present invention, the power transmission and distribution component includes a transformer body constituted by an iron core and a coil, and is a pole-mounted transformer.

[0021] In this aspect, the power transmission and distribution component includes a transformer body composed of an iron core and a coil, and the power transmission and distribution equipment is a pole-mounted transformer. In manufacturing the pole-mounted transformer, by using a case metal fitting and a cover fastening nut equipped with a posture restricting portion and a rotation permitting portion, work efficiency can be improved when assembling the case metal fitting and the cover fastening nut when attaching the cover to the case. [Effects of the Invention]

[0022] It is possible to provide power transmission and distribution equipment that improves work efficiency when assembling the case metal fittings and the cover tightening nuts when attaching a cover to the case of the power transmission and distribution equipment. [Brief explanation of the drawings]

[0023] [Figure 1]1 is a schematic diagram showing the configuration of a main part of a pole transformer (power transmission and distribution equipment) according to a first embodiment. [Figure 2] FIG. 2 is a schematic diagram showing a case metal fitting. [Figure 3] FIG. 4 is a plan view showing a cover tightening nut. [Figure 4] FIG. [Figure 5] FIG. 4 is a side view showing a cover tightening nut. [Figure 6] FIG. 10 is a schematic diagram showing a state in which the cover tightening nut is placed on the case metal fitting. [Figure 7] FIG. 10 is a side cross-sectional view showing the cover tightening nut placed on the case metal fitting. [Figure 8] 10 is a schematic diagram showing a state in which a clamping bolt fitted into a cover clamping nut is tightened (tightened state). FIG. [Figure 9] 10 is a schematic diagram showing a state in which a clamping bolt fitted into a cover clamping nut is loosened and rotated (loosely fitted state). FIG. [Figure 10] FIG. 10 is a schematic diagram showing a case metal fitting according to a second embodiment (elliptical flange portion). [Figure 11] FIG. 4 is a plan view showing a cover tightening nut. [Figure 12] FIG. [Figure 13] FIG. 4 is a side view showing a cover tightening nut. [Figure 14] FIG. 10 is a schematic diagram showing a state in which the cover tightening nut is placed on the case metal fitting. [Figure 15] FIG. 10 is a side cross-sectional view showing the cover tightening nut placed on the case metal fitting. [Figure 16] 10 is a schematic diagram showing a state in which a clamping bolt fitted into a cover clamping nut is tightened (tightened state). FIG. [Figure 17] 10 is a schematic diagram showing a state in which a clamping bolt fitted into a cover clamping nut is loosened and rotated (loosely fitted state). FIG. [Figure 18] FIG. 10 is a plan view showing a cover tightening nut according to a third embodiment (circular flange portion). [Figure 19] FIG. [Figure 20] FIG. 4 is a side view showing a cover tightening nut. DETAILED DESCRIPTION OF THE INVENTION

[0024] (Embodiment 1) Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a schematic diagram showing the configuration of a main part of a pole transformer 1 (power transmission and distribution equipment) according to the first embodiment. The power transmission and distribution equipment is, for example, a pole transformer 1 having a transformer body including a coil and an iron core. The pole transformer 1 (power transmission and distribution equipment) includes a case 11 (housing) that houses power transmission and distribution components such as the transformer body including the coil and the iron core, and a cover 12 (lid) that closes an opening 111 formed at the top of the case 11. In this embodiment, the power transmission and distribution equipment is described as being a pole transformer 1, but is not limited thereto. The power transmission and distribution equipment may include, for example, a case 11 and cover 12 that house power transmission and distribution components such as a voltage regulator such as an LVR or SVR, ground equipment, etc.

[0025] The pole transformer 1 includes, for example, a cylindrical case 11 and a cover 12. Power transmission and distribution components such as a coil and an iron core are housed inside the case 11, which is filled with insulating oil. The case 11 is provided with a primary bushing and a secondary bushing, and may further have a heat sink arranged along the circumferential direction. A circular opening 111 is formed in the top of the cylindrical case 11, and a circular cover 12 is arranged on the top of the case 11 to close the opening 111.

[0026] The outer diameter of the cover 12 is set larger than the inner diameter of the opening 111 of the case 11, and by placing the cover 12 on top of the case 11, the case 11 can be sealed. A plurality of (four in this embodiment) case metal fittings 3 are fixed to the outer periphery of the metal case 11 by, for example, welding. As will be described in detail later, each case metal fitting 3 is composed of two protruding pieces 31 arranged in the circumferential direction of the case 11. A cover fastening nut 5 is placed on the case metal fitting 3. Then, a fastening bolt 4 passing through a clamping metal fitting 2 is screwed into the cover fastening nut 5, so that the clamping metal fitting 2 presses the cover 12 from above, ensuring a seal between the back surface of the cover 12 and the periphery of the opening 111 of the case 11.

[0027] FIG. 2 is a schematic diagram showing the case metal fitting 3. Each case metal fitting 3 arranged along the outer circumferential surface of the case 11 of the pole transformer 1 is composed of two protruding pieces 31. Like the case 11, the protruding pieces 31 are made of a metal such as iron. These protruding pieces 31 are formed, for example, from crank-shaped plate members and protrude from the outer circumferential surface of the case 11. That is, each protruding piece 31 has a base end that protrudes from the outer circumferential surface of the case 11 and a tip end that protrudes therefrom, and the base end is formed in the up-down direction, i.e., vertical direction. The two protruding pieces 31 constituting the case metal fitting 3 are arranged adjacent to each other along the circumferential direction of the outer circumferential surface of the case 11. That is, the two protruding pieces 31 are arranged side by side with the inner surfaces of the protruding pieces 31 facing each other in the circumferential direction. The distance between the inner surfaces of the protruding pieces 31 is set to, for example, about 25 mm.

[0028] The protruding pieces 31 are formed with insertion holes 32 through which the cover fastening nuts 5 are inserted. When the cover fastening nuts 5 are inserted into the insertion holes 32 of the two protruding pieces 31 that make up the case metal fitting 3, the insertion direction of the cover fastening nuts 5 is parallel to a tangent to the position where the case metal fitting 3 is provided on the case 11, which forms the circular outer periphery. In other words, an imaginary line connecting the insertion holes 32 of the two adjacent protruding pieces 31 is parallel to the tangent to the position where the case metal fitting 3 is provided (the tangent to the circle formed by the outer periphery of the case 11).

[0029] The insertion hole 32 may be formed, for example, by punching the protruding piece 31. In this case, the insertion hole 32 is formed by an inner surface generated by the punching process, and the area surrounded by the inner surface corresponds to the insertion hole 32. The insertion hole 32 is formed in the center of the protruding piece 31. The insertion hole 32 is formed in an elongated hole shape along the protruding direction of the protruding piece 31. That is, with respect to the inner surface forming the insertion hole 32, both ends in the protruding direction, i.e., the inner surface on the base end side and the inner surface on the tip end side, are formed in a curved shape such as a semicircle, and the inner surface of the intermediate portion located between the base end side and the tip end side is formed in a linear shape. The curved inner surface (the inner surface on the base end side and the tip end side) includes side surfaces that form the left and right ends of the insertion hole 32. Therefore, the side surfaces (the inner surface on the base end side and the tip end side) that form the insertion hole 32 are curved surfaces. The linear inner surface (the inner surface on the intermediate portion) includes a bottom surface that forms the lower part of the insertion hole 32 and a top surface that forms the upper part of the insertion hole 32. Therefore, the bottom and top surfaces that form the insertion hole 32 are flat.

[0030] A posture restricting portion 321 is formed by the bottom surface that forms the lower portion of the insertion hole 32. Because the bottom surface is flat, when the cover clamping nut 5 is inserted into the insertion hole 32 of the case metal fitting 3, the lower surface 502 of the cover clamping nut 5 rests on the bottom surface of the insertion hole 32. At this time, because the lower surface 502 of the cover clamping nut 5 is also formed flat like the bottom surface of the insertion hole 32, the lower surface 502 of the cover clamping nut 5 and the bottom surface of the insertion hole 32 face each other and come into surface contact, restricting the posture of the cover clamping nut 5 and stabilizing the placed state. In other words, the flat bottom surface that forms the lower portion of the insertion hole 32 functions as a posture restricting portion 321 that restricts and stabilizes the posture of the cover clamping nut 5. The width of the bottom surface that functions as the posture regulating portion 321 (the length in the protruding direction of the protruding piece 31) may be set to, for example, 1 to 1.2 times the width of the cover fastening nut 5 (the length perpendicular to the insertion direction and up-down direction of the cover fastening nut 5), which is rectangular when viewed in cross section in the insertion direction.

[0031] The rotation permitting portion 322 is formed by the side surfaces that form the left and right ends of the insertion hole 32. In the height direction of the insertion hole 32, the rotation permitting portion 322 is located higher than the position restricting portion 321. The side surfaces that form the insertion hole 32 are formed in a curved shape that bulges outward from the insertion hole 32. In other words, the insertion hole 32 has a shape in which the width gradually increases from the lower part, which is the bottom surface, to the upper part. Therefore, the rotation permitting portion 322 is formed wider than the position restricting portion 321. In this case, the maximum width of the rotation permitting portion 322 is set to, for example, about 1.5 times the width of the position restricting portion 321, and may further be longer than the length of the diagonal of the cross section (rectangular cross section) of the cover tightening nut 5 in the insertion direction into the insertion hole 32.

[0032] By positioning the cover clamping nut 5 in the rotation permitting portion 322, i.e., by positioning it near the center in the height direction of the insertion hole 32, the cover clamping nut 5 can rotate around the insertion direction as a rotation axis when inserted into the insertion hole 32. In this way, the portion of the insertion hole 32 that is the widest functions as the rotation permitting portion 322. In the present embodiment, the rotation permitting portion 322 is formed by curved side surfaces, but this is not limited to this. The side surfaces that form the rotation permitting portion 322 may be flat, and may be tapered or inverted trapezoidal so that the inter-face distance between these flat side surfaces increases from bottom to top.

[0033] A portion that is pressed during fastening is formed by the top surface that forms the upper part of the insertion hole 32. The width of the top surface (the portion that is pressed during fastening) that forms the upper part of the insertion hole 32 may be the same as the width of the bottom surface (the position control portion 321) that forms the lower part of the insertion hole 32. As will be described in detail later, by tightening the clamping bolt 4 engaged with the cover clamping nut 5, the cover clamping nut 5 moves upward from the bottom surface on which it is placed, and eventually the top surface 501 of the cover clamping nut 5 abuts against the top surface that forms the upper part of the insertion hole 32.

[0034] The top surface forming the upper part of insertion hole 32 is flat like the bottom surface, and top surface 501 of cover clamping nut 5, which is rectangular in cross section, is also flat like bottom surface 502. Therefore, when fastened with clamping bolt 4, top surface 501 of cover clamping nut 5 and the top surface forming the upper part of insertion hole 32 face each other and come into surface contact to press against each other, dispersing or balancing the stress generated when clamping bolt 4 is tightened in the area of ​​surface contact, thereby stabilizing the fastening state of clamping bolt 4.

[0035] FIG. 3 is a plan view showing the cover clamping nut 5. FIG. 4 is a front view showing the cover clamping nut 5. FIG. 5 is a side view showing the cover clamping nut 5. The cover clamping nut 5 has a rectangular rod shape in cross section. The longitudinal length of the lower surface 502 of the cover clamping nut 5 is longer than the face-to-face distance between the outer surfaces of the two protruding pieces 31 that constitute the case fitting 3. The lateral length of the lower surface 502 of the cover clamping nut 5 is equal to or less than the bottom surface that forms the insertion hole 32 of the protruding piece 31, i.e., the width of the posture regulating portion 321 (the length of the protruding piece 31 in the protruding direction). The face-to-face distance between the upper surface 501 and the lower surface 502 of the cover clamping nut 5, i.e., the height of the cover clamping nut 5, is smaller than the face-to-face distance between the top surface and the bottom surface that form the insertion hole 32 of the protruding piece 31, and may be set to, for example, 50% to 60% of the face-to-face distance between the top surface and the bottom surface.

[0036] The cover clamping nut 5 has a rectangular upper surface 501 and a lower surface 502, and is formed with a threaded hole 51 that penetrates from the upper surface 501 to the lower surface 502. The axial direction of the threaded hole 51 is perpendicular to the upper surface 501 and the lower surface 502. The diameter of the threaded hole 51 is set to, for example, M12 (12 mm diameter). The cover clamping nut 5 is configured so that when it is placed on the case metal fitting 3, that is, when it is inserted into each of the insertion holes 32 of the two protruding pieces 31 that constitute the case metal fitting 3 and placed on the bottom surface that forms the insertion hole 32 (positioned on the posture regulating portion 321), the axial direction of the threaded hole 51 is the same as the axial direction of the clamping bolt 4 inserted into the through hole 211 of the retaining metal fitting 2. That is, the bottom surface (posture control portion 321) forming the insertion hole 32 of the case fitting 3, the screw hole 51 of the cover tightening nut 5, and the through hole 211 of the clamping fitting 2 are arranged so that the through hole 211 of the clamping fitting 2 is positioned on the axial extension line of the screw hole 51 of the cover tightening nut 5 arranged on the case fitting 3.

[0037] A protrusion 523 is formed on the underside 502 of the cover clamping nut 5. The protrusion 523 functions as an engagement portion 52 that engages with the outer surface of the protrusion piece 31 when the cover clamping nut 5 is inserted into the insertion hole 32 of the protrusion piece 31. The protrusions 523 that protrude downward from the underside 502 are formed on both ends of the underside 502 of the cover clamping nut 5, i.e., on the front and rear in the direction in which the cover clamping nut 5 is inserted into the insertion hole 32 (insertion direction). The protrusion length of the protrusion 523 may be set to, for example, about 1 / 10 of the inter-surface distance from the upper surface 501 to the lower surface 502 of the cover clamping nut 5.

[0038] The inter-face distance between the inner surfaces of the two protrusions 523 provided at both ends in the insertion direction may be set to, for example, 1 to 1.2 times the inter-face distance between the outer surfaces of the two protrusions 31 that constitute the case metal fitting 3. When the cover clamping nut 5 is inserted into each of the insertion holes 32 of the two protrusions 31, the protrusions 523 (engagement portions 52) formed on the lower surface 502 of the cover clamping nut 5 sandwich the two protrusions 31 from the outside, allowing efficient positioning when the cover clamping nut 5 is inserted into the insertion holes 32.

[0039] Fig. 6 is a schematic diagram showing the cover fastening nut 5 placed on the case metal fitting 3. Fig. 7 is a side cross-sectional view showing the cover fastening nut 5 placed on the case metal fitting 3. During the manufacturing stage of the power transmission and distribution equipment, a step of placing the cover fastening nut 5 on the case metal fitting 3 is carried out as a preliminary step to the step of screwing (screwing) the fastening bolt 4 into the cover fastening nut 5 and tightening it. At this time, a step of inserting the cover fastening nuts 5 into the insertion holes 32 of two adjacent protruding pieces 31 is carried out.

[0040] By inserting the cover fastening nut 5 into each of the insertion holes 32 of the two protruding pieces 31, the cover fastening nut 5 is placed across these two insertion holes 32. As a result, when the fastening bolt 4 is screwed into the threaded hole 51 of the cover fastening nut 5, rotation of the cover fastening nut 5 around the axis of the fastening bolt 4 is limited (regulated).

[0041] In this way, when placing the cover clamping nut 5 on the case fitting 3, a process is performed in which the underside 502 of the cover clamping nut 5 is aligned with the lower part of the insertion hole 32 (the bottom surface that forms the insertion hole 32) and inserted into the insertion hole 32. As a result, the planar underside 502 of the cover clamping nut 5 is positioned on the planar bottom surface that forms the insertion hole 32 (the position restriction portion 321), thereby restricting and stabilizing the position of the cover clamping nut 5. In this position, the through hole 211 of the clamping fitting 2 is positioned on an axial extension of the screw hole 51 of the cover clamping nut 5. Therefore, the clamping bolt 4 inserted into the through hole 211 of the clamping fitting 2 can be efficiently engaged (screwed) with the screw hole 51 of the cover clamping nut 5.

[0042] Convex portions 523 are formed on both ends of the underside 502 of the cover clamping nut 5, and these two convex portions 523 function as engaging portions 52 that engage with the outer surfaces of the adjacent protruding pieces 31, respectively. The convex portions 523 functioning as engaging portions 52 in this manner enable efficient positioning of the cover clamping nut 5 when it is inserted into the insertion hole 32. This improves work efficiency when assembling the case metal fitting 3 and the cover clamping nut 5, thereby reducing the number of steps required by the manufacturer. Even when at least part of the manufacturing process is automated using an FA device such as an automatic tightening machine, the application of the posture regulating portion 321 allows a series of processes, such as assembling the case metal fitting 3 and the cover clamping nut 5 and screwing the clamping bolt 4, to be automated.

[0043] Fig. 8 is a schematic diagram showing the state in which the clamping bolt 4 fitted into the cover clamping nut 5 is tightened (tightened engagement state). Fig. 9 is a schematic diagram showing the state in which the clamping bolt 4 fitted into the cover clamping nut 5 is loosened and rotated (loose engagement state). The clamping bracket 2 is an L-shaped metal plate member, and has a horizontal plate portion 21 that is horizontal to the upper surface 501 of the cover 12, and a vertical plate portion 22 that is perpendicular to the upper surface 501 of the cover 12.

[0044] A through hole 211 is formed near the center of the horizontal plate portion 21, and the fastening bolt 4 is inserted from above downward into the through hole 211. The tip of the fastening bolt 4 that passes through the through hole 211 reaches the screw hole 51 of the cover fastening nut 5, and by rotating the fastening bolt 4, the fastening bolt 4 fits (screws) into the screw hole 51 of the cover fastening nut 5.

[0045] By tightening the clamping bolt 4 fitted into the cover clamping nut 5, the distance between the cover clamping nut 5 and the clamping bolt 4 narrows, causing the head of the clamping bolt 4 to press the clamping metal fitting 2 downward. The pressed clamping metal fitting 2 presses the cover 12 downward, thereby sealing the opening 111 of the case 11 with the cover 12. When the clamping bolt 4 fitted into the cover clamping nut 5 is tightened in this way (tightened engagement state), the cover clamping nut 5 moves to the top of the insertion hole 32 and presses the top of the insertion hole 32, i.e., the top surface that forms the insertion hole 32, depending on the tightening torque of the clamping bolt 4.

[0046] By loosening the clamping bolt 4 fitted into the cover clamping nut 5 (bringing it into a loosely fitted state), the cover clamping nut 5 moves from above to below in the insertion hole 32, and is positioned at the middle (center) position in the height direction of the insertion hole 32, i.e., at a position corresponding to the rotation permitting portion 322. The rotation permitting portion 322 is formed wider than the attitude restricting portion 321, and the width of the rotation permitting portion 322, i.e., the maximum width of the insertion hole 32, is set to be equal to or greater than the diagonal length of the cross section (rectangular cross section) of the cover clamping nut 5 in the insertion direction into the insertion hole 32.

[0047] The clamping bolt 4 fitted into the cover clamping nut 5 is tightened (tightened engagement state), and the cover clamping nut 5 is moved from above to below to a position corresponding to the rotation allowance portion 322. As a result, with the cover clamping nut 5 engaged with the clamping bolt 4, it can be rotated (pivoted) within a range of, for example, 0° to 40° around the insertion direction of the cover clamping nut 5 as the central axis. Therefore, while maintaining the cover clamping nut 5 engaged with the clamping bolt 4, the clamping bolt 4 can be moved to a position removed from above the cover 12, and when performing maintenance work on the pole transformer 1, the cover 12 can be removed from the case 11 without interference between the clamping bolt 4 and the cover 12.

[0048] (Embodiment 2) 10 is a schematic diagram showing a case metal fitting 3 according to embodiment 2 (elliptical flange portion 524). The case metal fitting 3 of embodiment 2 has the same external shape as embodiment 1 and is composed of two protruding pieces 31 formed adjacent to each other along the circumferential direction of the outer periphery of the cover 12.

[0049] An insertion hole 32 is formed in the protruding piece 31, and the insertion hole 32 corresponds to an area surrounded by an inner surface. The inner surface forming the insertion hole 32 includes a flat bottom surface, a curved top surface, and flat side surfaces interposed between the bottom surface and the top surface. In other words, the lower part of the insertion hole 32 is formed in a straight line, and the upper part is formed in a curved shape that forms a semicircle that bulges upward.

[0050] The linearly formed lower portion of the insertion hole 32 functions as an attitude restricting portion 321, and the curved upper portion of the insertion hole 32 functions as a rotation permitting portion 322. The attitude restricting portion 321 located at the lower portion of the insertion hole 32 is formed by a flat bottom surface and flat side surfaces located at both ends of the bottom surface, forming a rectangular shape. The rotation permitting portion 322 located at the upper portion of the insertion hole 32 is formed by a curved top surface and forms a semicircular shape. Therefore, since the semicircular rotation permitting portion 322 is located above the rectangular attitude restricting portion 321 in the insertion hole 32, the insertion hole 32 forms an inverted U shape (an inverted U shape).

[0051] Fig. 11 is a plan view showing the cover clamping nut 5. Fig. 12 is a front view showing the cover clamping nut 5. Fig. 13 is a side view showing the cover clamping nut 5. The cover clamping nut 5 includes a rod portion 53 having a flat lower surface 502 and a curved upper surface 501, and a flange portion 524 provided on the end of the rod portion 53.

[0052] The lower surface 502 of the rod portion 53 is flat, and the upper surface 501 is a curved surface that bulges upward, so that the rod portion 53 has a semicircular shape when viewed in cross section in the longitudinal direction. The diameter of the semicircular rod portion 53 (the diameter of the semicircle when viewed in cross section) is set to be equal to or less than the width of the position restricting portion 321, which is the minimum width of the insertion hole 32 of the protruding piece 31. The diameter of the semicircular rod portion 53 may be set to be, for example, between 0.7 and 1 times the width of the position restricting portion 321, i.e., the width of the bottom plate that forms the lower part of the insertion hole 32 (the length in the protruding direction of the protruding piece 31).

[0053] An elliptical flange portion 524 is provided at one longitudinal end of the rod portion 53. The major axis of the elliptical flange portion 524 is larger than the diameter of the semicircular rod portion 53. Furthermore, the major axis of the elliptical flange portion 524 is larger than the maximum width of the insertion hole 32 of the protruding piece 31, i.e., the width of the rotation allowance portion 322.

[0054] The flange portion 524 is provided on only one end (one end) of both longitudinal ends of the rod portion 53, and is located at the rear end in the direction (insertion direction) in which the cover fastening nut 5 is inserted into the insertion hole 32 of the protruding piece 31. By providing the flange portion 524 at the end of the rod portion 53 at the rear end in the insertion direction in this way, when the cover fastening nut 5 is placed in the case metal fitting 3, as the tip of the rod portion 53 is inserted into the insertion hole 32, the inner surface of the flange portion 524 abuts against the outer surface of the protruding piece 31, restricting further insertion of the cover fastening nut 5 and making it possible to position the cover fastening nut 5 when it is inserted into the insertion hole 32.

[0055] A screw hole 51 is formed in the rod portion 53 so as to extend from the curved upper surface 501 to the flat lower surface 502. The axial direction of the screw hole 51 is perpendicular to the flat lower surface 502. By forming the screw hole 51 so that its axial direction faces perpendicular to the flat lower surface 502 in this manner, when the cover tightening nut 5 is placed in the case metal fitting 3, that is, when it is placed in a position corresponding to the posture restricting portion 321, the axial direction of the screw hole 51 can be directed toward the through hole 211 of the retaining metal fitting 2 that is located above (directly above) the screw hole 51 in the vertical direction. This allows these fastening parts to be efficiently positioned so that the centers of the screw hole 51 and the through hole 211 are aligned on a straight line.

[0056] In the longitudinal direction of the rod portion 53, the screw hole 51 is formed offset from the center in the longitudinal direction toward the end portion where the flange portion 524 is provided. In other words, when the center of the screw hole 51 is used as a reference, the length from the center of the screw hole 51 to the end portion of the rod portion 53 where the flange portion 524 is provided is shorter than the length to the end portion of the rod portion 53 where the flange portion 524 is not provided.

[0057] The distance from the center of the screw hole 51 to the flange portion 524 is set to half (½) of the distance between the outer surfaces of the two protruding pieces 31 that make up the case metal fitting 3. Therefore, when the cover fastening nut 5 is placed on the case metal fitting 3, the end of the rod portion 53 that is not provided with the flange portion 524 can be positioned at a position that passes through the insertion hole 32 of the protruding piece 31. This makes it possible to prevent the cover fastening nut 5 from falling off the case metal fitting 3 during the process of placing the cover fastening nut 5 on the case metal fitting 3.

[0058] FIG. 14 is a schematic diagram showing the cover clamping nut 5 placed on the case fitting 3. FIG. 15 is a side cross-sectional view showing the cover clamping nut 5 placed on the case fitting 3. As in the first embodiment, in this embodiment, a process is performed in which the cover clamping nuts 5 are inserted into the insertion holes 32 of the protruding pieces 31 of two adjacent case fittings 3. That is, when placing the cover clamping nuts 5 on the case fitting 3, a process is performed in which the lower surface 502 of the cover clamping nut 5 is aligned with the lower part of the insertion hole 32 (the bottom surface forming the insertion hole 32) and inserted into the insertion hole 32. As a result, the planar lower surface 502 of the cover clamping nut 5 is positioned on the planar bottom surface forming the insertion hole 32 (the position restriction portion 321), thereby restricting and stabilizing the position of the cover clamping nut 5. In this position, the through hole 211 of the retaining bracket 2 is positioned on the axial extension of the screw hole 51 of the cover clamping nut 5. Therefore, the clamping bolt 4 inserted into the through hole 211 of the clamping metal fitting 2 can be efficiently engaged (screwed) with the screw hole 51 of the cover clamping nut 5 .

[0059] A flange portion 524 is formed on the end of the rod portion 53 of the cover clamping nut 5, and when the tip of the rod portion 53 is inserted into the insertion hole 32 of the protruding piece 31, the inner surface of the flange portion 524 ultimately abuts against the outer surface of the protruding piece 31, causing the flange portion 524 to engage with the protruding piece 31 (the protruding piece 31 on the near side in the insertion direction). By having the flange portion 524 function as the engaging portion 52 that engages with the protruding piece 31 in this way, a stop can be achieved when the cover clamping nut 5 is inserted into the insertion hole 32 of the protruding piece 31. Therefore, the stop achieved by the flange portion 524 allows efficient positioning of the cover clamping nut 5 when it is inserted into the insertion hole 32.

[0060] Fig. 16 is a schematic diagram showing the state in which the clamping bolt 4 fitted into the cover clamping nut 5 is tightened (tightened engagement state). Fig. 17 is a schematic diagram showing the state in which the clamping bolt 4 fitted into the cover clamping nut 5 is loosened and rotated (loosely fitted state). By tightening the clamping bolt 4 fitted into the cover clamping nut 5, the distance between the cover clamping nut 5 and the clamping bolt 4 is reduced, causing the head of the clamping bolt 4 to press the clamping metal fitting 2 downward. The pressed clamping metal fitting 2 presses the cover 12 downward, thereby sealing the opening 111 of the case 11 with the cover 12.

[0061] When the clamping bolt 4 fitted into the cover clamping nut 5 is tightened (tightened state), the cover clamping nut 5 moves to the top of the insertion hole 32 and presses against the top of the insertion hole 32, i.e., the top surface that forms the insertion hole 32, in accordance with the tightening torque of the clamping bolt 4. At this time, the curved top surface 501 of the cover clamping nut 5 and the curved top surface that forms the through hole 211 may have the same radius of curvature, and the top surface 501 of the cover clamping nut 5 and the curved top surface that forms the through hole 211 may be in surface contact. As a result, when the clamping bolt 4 fitted into the cover clamping nut 5 is tightened (tightened state), the pressing force (stress) generated between the cover clamping nut 5 and the protruding piece 31 is dispersed over the area of ​​surface contact, stabilizing the tightened state.

[0062] By loosening the clamping bolt 4 fitted into the cover clamping nut 5 (setting it into a loosely fitted state), the cover clamping nut 5 moves from above to below in the insertion hole 32, and the pressing state between the cover clamping nut 5 and the protruding piece 31 is released. In other words, when the upper surface 501 of the cover clamping nut 5 moves away from the top surface that forms the insertion hole 32, the cover clamping nut 5 is positioned inside the insertion hole 32 at a location corresponding to the rotation allowance portion 322.

[0063] The rotation permitting portion 322 has a curved (semicircular) shape, similar to the upper surface 501 of the cover clamping nut 5. Therefore, by tightening the clamping bolt 4 fitted to the cover clamping nut 5 (tightened engagement state) and moving the cover clamping nut 5 from above to below and positioning it at a location corresponding to the rotation permitting portion 322, the cover clamping nut 5 can be rotated (turned) within a range of, for example, 0° to 40° around the insertion direction of the cover clamping nut 5 as a central axis in a state where the cover clamping nut 5 is engaged with the clamping bolt 4.

[0064] (Embodiment 3) FIG. 18 is a plan view showing a cover clamping nut 5 according to embodiment 3 (circular flange portion 524). FIG. 19 is a front view showing the cover clamping nut 5. FIG. 20 is a side view showing the cover clamping nut 5. The cover clamping nut 5 of this embodiment comprises a rod portion 53 having a flat lower surface 502 and a curved upper surface 501, as in embodiment 2, and a flange portion 524 provided at the end of the rod portion 53. The cover clamping nut 5 of this embodiment is arranged on the case fitting 3 of embodiment 2.

[0065] Flange portion 524 of the present embodiment is circular and is provided at one end of rod portion 53, similarly to embodiment 1. The diameter of circular flange portion 524 is set to be the same as the diameter of rod portion 53, which is semicircular in cross section. With flange portion 524 thus circular, it is possible to achieve the same actions and effects as flange portion 524 of embodiment 1.

[0066] The embodiments disclosed herein are to be considered as illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above meaning, and is intended to include all modifications within the meaning and scope of the claims.

[0067] Multiple claims in the claims section may be combined with each other regardless of the form of reference. Multiple dependent claims are defined in the claims section, depending on multiple claims. Multiple dependent claims may not be defined in the claims section, but multiple dependent claims may be defined that depend on multiple dependent claims. [Explanation of symbols]

[0068] 1 Pole transformer (power transmission and distribution equipment), 10 Power transmission and distribution component, 11 Case, 111 Opening, 12 Cover, 2 Retaining bracket, 21 Horizontal plate portion, 211 Through hole, 22 Vertical plate portion, 3 Case bracket, 31 Protruding piece, 32 Insertion hole, 321 Posture control portion, 322 Rotation allowance portion, 4 Fastening bolt, 5 Cover fastening nut, 501 Upper surface, 502 Lower surface, 51 Screw hole, 52 Engagement portion, 523 Convex portion, 524 Flange portion, 53 Rod portion

Claims

1. A case for storing power transmission and distribution components; a cover that detachably covers an opening provided in the case; a case metal fitting provided on an outer peripheral surface of the case; a retaining metal fitting that engages with the case metal fitting to hold down the cover; a fastening bolt inserted into a through hole formed in the clamp; a cover fastening nut disposed on the case metal fitting and engaged with the fastening bolt; A power transmission and distribution facility comprising: the case metal fitting includes an attitude regulation portion that regulates the attitude of the cover fastening nut so that an axial direction of a threaded portion of the cover fastening nut faces the through hole, A rotation permitting portion is formed above the position restricting portion, which permits rotation of the cover fastening nut when the cover fastening nut is engaged with the fastening bolt. Power transmission and distribution equipment.

2. the case metal fitting includes two protruding pieces extending in a circumferential direction on an outer peripheral surface of the case, Each of the protruding pieces has an insertion hole through which the cover fastening nut is inserted, the position restriction portion is configured by a flat bottom surface on an inner surface forming the insertion hole, The cover tightening nut has a flat lower surface, The lower surface of the cover fastening nut is placed on the bottom surface of the position regulating portion, whereby the position regulating portion regulates the position of the cover fastening nut. The power transmission and distribution facility according to claim 1 .

3. the rotation allowing portion and the attitude restricting portion are configured by the inner surface forming the insertion hole, The rotation allowing portion is formed to be wider than the attitude restricting portion, The cover tightening nut has a rectangular shape when viewed in a cross section in the insertion direction of the insertion hole. The power transmission and distribution facility according to claim 2.

4. the rotation allowing portion and the attitude restricting portion are configured by the inner surface forming the insertion hole, The attitude regulation portion has a rectangular shape, The rotation allowing portion has a semicircular shape, The cover tightening nut has a semicircular shape when viewed in a cross section in the insertion direction of the insertion hole. The power transmission and distribution facility according to claim 2.

5. The cover tightening nut has an engaging portion that engages with at least one of the protruding pieces when inserted into the insertion holes formed in the two protruding pieces. The power transmission and distribution facility according to claim 2.

6. The engaging portion is configured by a convex portion provided on the lower surface of the cover tightening nut. The power transmission and distribution facility according to claim 5.

7. The engaging portion is configured by a flange portion provided at the end of the cover tightening nut. The power transmission and distribution facility according to claim 5.

8. the power transmission and distribution component includes a transformer body configured with an iron core and a coil, It is a pole-mounted transformer The power transmission and distribution facility according to any one of claims 1 to 7.

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