transformer

Abstract

The present invention provides a transformer that prevents the problems associated with soldering and allows for easy connection of connecting members to tapped wires. [Solution] A transformer comprising a molded coil in which a tap change terminal 81 is fixed to a tap wire 101 of a wound body 102 that extends along the outer circumferential surface of the wound body 102, wherein the transformer comprises a crimp terminal 84 attached to the end of the tap wire 101 and a connecting member 83 that connects the crimp terminal 84 and the tap change terminal 81, the connecting member 83 having a coupling portion 831 for coupling with the tap change terminal 81 and a threaded rod portion 832 provided closer to the wound body 102 than the coupling portion 831, and is fixed to the crimp terminal 84 by screwing the threaded rod portion 832 and a nut 86.

Description

Technical Field

[0001] The present invention relates to a transformer.

Background Art

[0002] Conventionally, an insulating tap changer for switching taps in a transformer has been used. Such an insulating tap changer is attached to an earth terminal provided on a core clamping metal fitting for fixing a wound core having a coil. (See Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a molded transformer having a resin-molded primary coil and a secondary coil disposed inside the primary coil and resin-molded, the primary coil and the secondary coil are erected, and a tap switching portion is provided on the outer peripheral surface of the primary coil and is exposed.

[0005] Such a tap switching portion has a switching terminal, and the switching terminal is coupled to a connecting member such as an insert nut attached to a tap wire from the primary coil. Generally, the connecting member is soldered to the tap wire, and a strongly acidic flux is used for soldering, so it is necessary to wipe off the remaining flux after soldering. However, the flux that has not been wiped off completely causes corrosion of the tap wire. Also, due to the heat generation of the tap wire during the operation of the molded transformer, there is a risk that the joint portion of the connecting member and the tap wire melts.

[0006] This invention has been made in view of the above circumstances, and aims to provide a transformer that can prevent the aforementioned problems when using soldering and that can easily connect connecting members to tap wires. [Means for solving the problem]

[0007] The transformer according to the present invention is a transformer comprising a molded coil in which a tap change terminal is fixed to a lead wire of the winding body that extends along the outer circumferential surface of the winding body, the transformer comprising a terminal attached to the end of the lead wire and a connecting member for connecting the terminal and the tap change terminal, the connecting member having a coupling portion for the tap change terminal and a threaded rod portion provided closer to the winding body than the coupling portion, and fixed to the terminal by screwing the threaded rod portion with a nut. [Effects of the Invention]

[0008] According to the present invention, it is possible to connect connecting members to tapped wires more easily while preventing the drawbacks associated with using soldering. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic front view showing the configuration of a three-phase molded transformer according to Embodiment 1. [Figure 2] This is a cross-sectional view taken along line II-II in Figure 1. [Figure 3] This is a perspective view showing the state in which the connecting member, crimp terminal, and tap wire are connected in the molded transformer according to Embodiment 1. [Figure 4] This is an exploded view showing the connecting component separated from the crimp terminal. [Figure 5] This is a partial cross-sectional view showing the configuration of the connecting member of a molded transformer according to Embodiment 1. [Figure 6] This is an explanatory diagram illustrating the method of connecting tap wires and crimp terminals in a molded transformer according to Embodiment 2. [Modes for carrying out the invention]

[0010] The present invention will be described below with reference to the drawings illustrating its embodiments.

[0011] (Embodiment 1) Figure 1 is a schematic front view showing the configuration of a three-phase molded transformer 100 according to Embodiment 1. The molded transformer 100 uses a molded coil 10 obtained by winding a conductor covered with insulating paper and then molding the resulting winding with a thermosetting resin composition such as epoxy resin.

[0012] The molded transformer 100 is equipped with three vertically mounted molded coils 10. The three molded coils 10 consist of a U-phase molded coil 10, a V-phase molded coil 10, and a W-phase molded coil 10. The three molded coils 10 are arranged side by side at a predetermined interval.

[0013] In the molded coil 10 of each phase, the primary coil is formed as a cylindrical body using a thermosetting resin composition, as described above. The secondary coil is also formed as a cylindrical body with a smaller diameter than the primary coil using a thermosetting resin composition, as described above.

[0014] Each phase molded coil 10 consists of a primary coil and a secondary coil inserted inside the primary coil, and the primary and secondary coils have a multi-cylinder shape. Each phase molded coil 10 is provided with a rectangular plate-shaped primary terminal 70 on the upper front side of its outer surface, corresponding to the primary coil of each phase. The primary terminal 70 is connected to the starting winding of the primary coil of each phase molded coil 10.

[0015] The iron core 20 is inserted inside the mold coil 10 (secondary coil) of each phase. The iron core 20 includes three vertical column portions 22 that penetrate vertically inside the secondary coil of the mold coil 10 of each phase, an upper cross column portion 21 that connects the upper ends of the three vertical column portions 22, and a lower cross column portion 23 that connects the lower ends of the three vertical column portions 22, forming an annular magnetic circuit. That is, the upper cross column portion 21 and the lower cross column portion 23 are respectively connected to the upper ends and the lower ends of the three vertical column portions 22 that extend out of the mold coil 10 of each phase. Also, a rectangular plate-shaped secondary terminal 60 corresponding to the secondary coil of each phase is provided at the upper end of the upper cross column portion 21.

[0016] The upper cross column portion 21 and the lower cross column portion 23 of the iron core 20 are respectively held by holding brackets 30. Each holding bracket 30 is made of, for example, H-shaped steel, extends along the upper cross column portion 21 and the lower cross column portion 23, and is disposed away from the mold coil 10 of each phase in the upward or downward direction. Legs 50 for standing the mold transformer 100 are attached to the lower surface of the lower holding bracket 30.

[0017] Insulating spacers 40 are interposed between the mold coil 10 of each phase and each holding bracket 3o. Specifically, a plurality of insulating spacers 40 are interposed between the upper end surface of the mold coil 10 of each phase and the lower surface of the upper holding bracket 30, and a plurality of insulating spacers 40 are interposed between the lower end surface of the mold coil 10 of each phase and the upper surface of the lower holding bracket 30.

[0018] The mold coil 10 of each phase has a tap-changing section 80 including a tap-changing terminal 81, and each tap-changing section 80 is provided on the outer peripheral surface of the corresponding mold coil 10 and at the lower part on the front side of such a mold transformer 100. Each tap-changing section 80 has the same shape.

[0019] Each tap switching section 80 has a plurality of tap switching terminals 81. Such a plurality of tap switching terminals 81 have the same shape. A tap wire 101 (see FIG. 2) drawn from the winding end wire of the winding body 102 related to the primary coil is connected to each tap switching terminal 81. Tap wires 101 related to windings with different numbers of turns are connected to each tap switching terminal 81 according to the tap voltage.

[0020] As described above, on the outer peripheral surface of the molded coil 10 of each phase, a plurality of tap switching terminals 81 are arranged in a fan shape at the lower part on the front side of the molded transformer 100. The tap wire 101 (lead wire) related to each tap switching terminal 81 is covered with a thermosetting resin. More specifically, the plurality of tap wires 101 are molded integrally with the thermosetting resin layer covering the winding body 102 (see FIG. 2) related to the primary coil of the molded coil 10. In the tap switching section 80, the wire mold section 82 (mold section) in which the plurality of tap wires 101 are molded bulges in a rectangular shape when viewed from the front of the molded transformer 100 from the outer peripheral surface of the molded coil 10.

[0021] FIG. 2 is a cross-sectional view taken along line II-II of FIG. 1. FIG. 2 is a cross-sectional view showing the vicinity of the tap switching terminal 81 including the tap switching terminal 81. For convenience of explanation, in FIG. 2, only the wire mold section 82 and the winding body 102 of the molded coil 10 are shown in a cross-sectional view, the tap switching terminal 81 is shown by a wavy line, and the switching piece P connecting the tap switching terminals 81 is shown by a dashed-dotted line.

[0022] Each tap wire 101 extends upward from the lower end side of the molded coil 10 along the winding body 102 of the molded coil 10, and the plurality of tap wires 101 related to the plurality of tap switching terminals 81 are arranged side by side in the circumferential direction of the winding body 102. That is, a tap switching terminal 81 is provided at the tip of each tap wire 101. Each tap wire 101 is connected to the tap switching terminal 81 via a crimp terminal 84 and a connecting member 83. In other words, the connecting member 83 connects the tap switching terminal 81 and the crimp terminal 84.

[0023] Figure 3 is a perspective view showing the state in which the connecting member 83, crimp terminal 84, and tap wire 101 are connected in the molded transformer 100 according to Embodiment 1, and Figure 4 is an exploded view showing the state in which the connecting member 83 is separated from the crimp terminal 84.

[0024] The tap wire 101 is made of aluminum, for example, has a rectangular cross-section, and extends vertically as described above. The tap wire 101 is not limited to this, and may, for example, have an elongated rectangular cross-section. A crimp terminal 84 is attached to the upper end of the tap wire 101.

[0025] The crimp terminal 84 is made of a deformable conductive metal and has a crimping portion 841 that is crimped and connected to the upper end of the tap wire 101. The crimping portion 841 surrounds the upper end of the tap wire 101 and has a cylindrical shape with the length of the tap wire 101 as its axial direction.

[0026] On one annular end face of the crimping portion 841, a hollow disc portion 842 with a circular through hole 843 is provided at the position furthest from the winding body 102 of the molded coil 10, in the radial direction of the molded coil 10 (see Figure 2). The hollow disc portion 842 is circular in shape and is provided on the crimping portion 841 such that the direction of the through hole 843 is in the radial direction of the molded coil 10. The crimping portion 841 and the hollow disc portion 842 are integrally formed.

[0027] As shown in Figure 2, the connecting member 83 is made of a conductive metal and has a coupling portion 831 that connects to the tap switching terminal 81 for electrical connection, and a threaded rod portion 832 that is provided closer to the wound body 102 of the molded coil 10 than the coupling portion 831.

[0028] Figure 5 is a partial cross-sectional view showing the configuration of the connecting member 83 of the molded transformer 100 according to Embodiment 1. For the sake of explanation, Figure 5 shows a cross-sectional view of a part of the connecting portion 831. In Figure 5, the position of the line molded portion 82 is indicated by a dashed line.

[0029] The connecting portion 831 has a substantially bottomed cylindrical shape and includes a cylindrical portion 8311 that extends radially in the direction of the molded coil 10, and an enlarged portion 8313 whose radial dimension is larger than that of the cylindrical portion 8311.

[0030] The cylindrical portion 8311 is provided at the joint portion 831 on the side opposite to the threaded rod portion 832, and has a cylindrical shape. A threaded portion 8312 for screwing into the tap change terminal 81 is formed on the inner circumferential surface of the cylindrical portion 8311.

[0031] The enlarged portion 8313 is plate-shaped and is provided on the other end side of the connecting portion 831. That is, the cylindrical portion 8311 is provided on one main surface side of the enlarged portion 8313, and the cylindrical portion 8311 and the enlarged portion 8313 are arranged on the same axis. Furthermore, the enlarged portion 8313 has a hexagonal shape. In other words, the other end of the connecting portion 831 on the side of the threaded rod portion 832 is angularly hexagonal.

[0032] As described above, the cylindrical portion 8311 and the enlarged portion 8313 have different radial dimensions of the connecting portion 831, and the enlarged portion 8313 is larger than the cylindrical portion 8311, so a stepped portion 833 is formed between the cylindrical portion 8311 and the enlarged portion 8313.

[0033] Furthermore, in the connecting member 83, a threaded rod portion 832 is provided in the center of the other main surface of the enlarged portion 8313. The threaded rod portion 832 is round and extends in the thickness direction of the enlarged portion 8313. A threaded portion for screwing with a nut 86, which will be described later, is formed on the outer circumferential surface of the threaded rod portion 832. The connecting portion 831 and the threaded rod portion 832 are integrally formed.

[0034] The connecting member 83 is fixed to the crimp terminal 84 by screwing it with the nut 86, and is electrically connected to the tap wire 101 via the crimp terminal 84. The fixing of the connecting member 83 will be described in detail below with reference to Figure 4.

[0035] The threaded rod portion 832 of the connecting member 83 is inserted into the through hole 843 of the hollow disc portion 842 from one side of the hollow disc portion 842. At this time, a so-called flat washer 87, which is hollow disc-shaped, is fitted onto the threaded rod portion 832, and the flat washer 87 is interposed between the hollow disc portion 842 of the crimp terminal 84 and the enlarged portion 8313 of the connecting member 83.

[0036] On the other side of the hollow disc portion 842, a flat washer 87 and a spring washer 85, which is roughly hollow and disc-shaped, are arranged in this order on the same axis as the hollow disc portion 842. The threaded rod portion 832, which is inserted into the through hole 843 of the hollow disc portion 842, is inserted into the flat washer 87 and the spring washer 85. A nut 86 is screwed onto the end of the threaded rod portion 832 that has come out of the spring washer 85. As a result, the connecting member 83 is fixed to the crimp terminal 84, as shown in Figure 3.

[0037] As described above, with the connecting member 83 fixed to the crimp terminal 84 and the tap wire 101 connected to the connecting member 83 via the crimp terminal 84, the thermosetting resin is molded to form the wire molded portion 82. The tap wire 101, the crimp terminal 84, and a portion of the connecting member 83 are covered by the wire molded portion 82. More specifically, as shown in Figures 2 and 5, the wire molded portion 82 covers the wound body 102 of the molded coil 10, and in the connecting member 83, it extends beyond the rod thread portion 832, the enlarged portion 8313, and the stepped portion 833, up to partway up the cylindrical portion 8311.

[0038] In this case, in the radial direction of the molded coil 10, the distance L2 from the winding body 102 of the molded coil 10 to the threaded rod portion 832 is greater than or equal to the distance L1 from the winding body 102 of the molded coil 10 to the crimping portion 841 (see Figure 2). In other words, in the radial direction of the molded coil 10, the tip of the threaded rod portion 832 of the connecting member 83 does not extend beyond the crimping portion 841 of the crimp terminal 84 toward the molded coil 10. This can be achieved, for example, by appropriately adjusting the length of the threaded rod portion 832.

[0039] As described above, in the molded transformer 100 according to Embodiment 1, a crimp terminal 84 is attached to the tip of the tap wire 101, and the connecting member 83 is fixed to the crimp terminal 84 by screwing the rod thread portion 832 of the connecting member 83 with the nut 86.

[0040] Therefore, the connecting member 83 and the tap wire 101 can be easily connected, improving work efficiency compared to the case where the connecting member is connected to the tap wire using soldering. Furthermore, compared to the case where soldering is used, problems such as corrosion due to residual flux and melting of the soldered part when the tap wire is overheated can be prevented.

[0041] Furthermore, as described above, in the molded transformer 100 according to Embodiment 1, a stepped portion 833 is formed between the cylindrical portion 8311 and the enlarged portion 8313 of the connecting member 83, and the wire molded portion 82 covers part of the cylindrical portion 8311 beyond the stepped portion 833. Because of this stepped portion 833, the connecting member 83 is firmly held by the wire molded portion 82.

[0042] Furthermore, as described above, in the molded transformer 100 according to Embodiment 1, the hollow disc portion 842 is provided at the position furthest from the winding body 102 of the molded coil 10 in the crimping portion 841 of the crimping terminal 84. Therefore, the insulation distance between the connecting member 83 (nut 86) and the winding body 102 of the molded coil 10 can be made as long as possible.

[0043] Furthermore, as described above, in the molded transformer 100 according to Embodiment 1, the distance L2 from the winding body 102 of the molded coil 10 to the threaded rod portion 832 of the connecting member 83 is greater than or equal to the distance L1 from the winding body 102 of the molded coil 10 to the crimping portion 841. Therefore, the insulation distance between the nut 86 of the connecting member 83 and the winding body 102 of the molded coil 10 can be maximized.

[0044] Furthermore, as described above, in the molded transformer 100 according to Embodiment 1, the enlarged portion 8313 causes the other end of the connecting portion 831 to be angularly hexagonal, which makes it easier to rotate and hold the connecting member 83 (threaded rod portion 832) when screwing it into the nut 86, thereby improving work efficiency.

[0045] In the above description, the example given is that the connecting member 83 is fixed to the crimp terminal 84 by screwing the rod thread portion 832 of the connecting member 83 to the nut 86, but the explanation is not limited to this. For example, in the crimp terminal 84, the crimp terminal 84 and the nut 86 may be integrally formed, or the nut 86 may be attached to the crimp portion 841 instead of the hollow disc portion 842.

[0046] Furthermore, although the above description uses the example of the tap wire 101 being made of aluminum, it is not limited to this, and the tap wire 101 may also be made of copper.

[0047] (Embodiment 2) In the molded transformer 100 according to Embodiment 2, a crimp terminal 84 is connected to the end of the tap wire 101, similar to Embodiment 1, but there is a difference in the method of connecting the tap wire 101 and the crimp terminal 84.

[0048] Figure 6 is an explanatory diagram illustrating the method of connecting the tap wire 101 and the crimp terminal 84 in the molded transformer 100 according to Embodiment 2. Figure 6A shows the end of the tap wire 101 to which the crimp terminal 84 is connected in the molded transformer 100 according to Embodiment 2, Figure 6B is a view in the direction of the arrow in Figure 6A, and Figure 6C shows a comparative example. In Figure 6, the position of the winding body 102 of the molded coil 10 is indicated by a dashed line.

[0049] In the molded transformer 100 according to Embodiment 2, similar to Embodiment 1, the tap wire 101 is made of aluminum and is strip-shaped, but the upper end of the tap wire 101 is folded along the length direction of the tap wire 101. Specifically, as shown in Figure 6B, the upper end of the tap wire 101 is valley-folded with the center of the width direction of the tap wire 101 as the fold line.

[0050] The crimp terminal 84 is made of a deformable conductive metal, and the crimping portion 841 of the crimp terminal 84 surrounds the upper end of the folded tap wire 101. More specifically, the crimping portion 841 surrounds the upper end of the tap wire 101, which is folded in half, in a cylindrical shape with the length of the tap wire 101 as its axis. In this case, the crimping portion 841 has an elliptical axial cross-section (see Figure 6B).

[0051] At the end face of the crimping portion 841, a hollow disc portion 842 with a circular through hole 843 is provided at the position furthest from the winding body 102 of the molded coil 10, in the radial direction of the molded coil 10. The hollow disc portion 842 is circular in shape and is provided on the crimping portion 841 such that the direction of penetration of the through hole 843 is in the radial direction of the molded coil 10.

[0052] Because of the above configuration, the molded transformer 100 according to Embodiment 2 can maximize the insulation distance between the nut 86 of the connecting member 83 and the winding body 102 of the molded coil 10, compared to the case where the tip of the tap wire 101 is not bent and is flat (hereinafter referred to as the other example) (see Figure 6C).

[0053] As shown in Figure 6, in the case of the molded transformer 100 according to Embodiment 2, the tip of the tap wire 101 is folded in half, so the position of the hollow disc portion 842 on the connecting member 83 is further away from the winding body 102 of the molded coil 10 by a distance L3 compared to the other example in Figure 6C. That is, although the distance L4 from the winding body 102 of the molded coil 10 to the crimping portion 841 of the crimp terminal 84 is the same, in the molded transformer 100 according to Embodiment 2, the hollow disc portion 842 is L3 further away and is separated from the winding body 102 of the molded coil 10 than in the other example.

[0054] Therefore, even if the length of the threaded rod portion 832 of the connecting member 83 fluctuates due to tolerances, design errors, etc., the tip of the threaded rod portion 832 of the connecting member 83 will not extend beyond the crimping portion 841 of the crimp terminal 84 towards the molded coil 10, and the insulation distance can be maintained.

[0055] Parts similar to those in Embodiment 1 are denoted by the same reference numerals, and detailed descriptions are omitted.

[0056] The technical features (constituent elements) described in Embodiments 1 and 2 are combinable with each other, and by combining them, new technical features can be conceived. The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims, not in the sense described above, and all modifications are intended to be in the sense and scope equivalent to the claims.

[0057] The matters described in each embodiment can be combined with each other. Furthermore, the independent and dependent claims described in the claims can be combined with each other in any combination, regardless of the form of reference. In addition, the claims use a form in which claims referencing two or more other claims (multi-claim form), but are not limited to this. A form in which multi-claims referencing at least one multi-claim (multi-multi-claim) may also be used. [Explanation of Symbols]

[0058] 10: Molded coil, 81: Tap change terminal, 82: Wire molded part (molded part), 83: Connecting member, 84: Crimp terminal (terminal), 86: Nut, 100: Molded transformer, 101: Tap wire (lead wire), 102: Winding body, 831: Joint part, 832: Rod thread part, 833: Stepped part, 841: Crimping part, 842: Hollow disc part (hollow plate part), 843: Through hole, 8311: Cylindrical part, 8313: Enlarged part, L1~L4: Distance

Claims

1. A transformer comprising a molded coil in which a tap-changing terminal is fixed to a lead wire of the winding body that extends along the outer surface of the winding body, A terminal attached to the end of the aforementioned lead wire, The system includes a connecting member for connecting the aforementioned terminal and the tap switching terminal, The aforementioned connecting member is It has a coupling portion with the tap switching terminal and a rod-threaded portion provided closer to the winding body than the coupling portion, A transformer fixed to the terminal by screwing the aforementioned threaded rod portion and nut together.

2. The connecting portion has a cylindrical portion extending radially in the direction of the molded coil at one end opposite to the threaded rod portion, and an enlarged portion at the other end whose radial dimension is larger than that of the cylindrical portion. The transformer according to claim 1, further comprising a molded portion that covers from the outer circumferential surface of the winding body to a part of the cylindrical portion.

3. The aforementioned terminal is A crimping portion that surrounds and connects the end of the leader wire in a cylindrical shape with the length direction of the leader wire as the axial direction, It has a through hole and a hollow plate portion provided in the crimping portion such that the direction of the through hole is the radial direction of the molded coil, The hollow plate portion is located at the position furthest from the winding body in the crimping portion. The transformer according to claim 1 or 2, wherein the threaded rod portion is inserted through the through hole of the hollow plate portion.

4. The transformer according to claim 3, wherein in the radial direction of the molded coil, the distance from the winding body to the threaded rod portion is greater than or equal to the distance from the winding body to the crimped portion.

5. The aforementioned leader line is strip-shaped, The transformer according to claim 3, wherein the end of the lead wire is bent along the length direction of the lead wire.

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