JP2008205212A - Transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transformer wherein its coupling degree is made high, and its occupied volume rate is improved, and further, its surge voltage is reduced. <P>SOLUTION: The transformer has: a second coil 63 wound around a core 10; a first coil 62 wherein it constitutes the other side of the first and second sides of the transformer, and a plurality of lead wires connected with a plurality of taps are wound around the core 10 adjacently to the second coil 63; and a third coil 64 wherein a plurality of lead wires connected with the same taps as the plurality of taps of the first coil 62 being connected therewith are so wound around the core 10 adjacently to the opposite side of the first coil 62 as to sandwich the second coil 63 between them and the coil 62. In the first and third coils 62, 64, a plurality of lead wires lined in parallel with each other are so formed respectively that the first coil 62 is wound around the core 10 spirally in a first layer from its outer-diameter side to its inner-diameter side, and that the third coil 64 is wound around the core 10 spirally in a second layer adjacent to the first layer from its inner-diameter side to its outer-diameter side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a transformer suitable for, for example, a switching power supply, and more particularly to a winding method and a composite method of a plurality of coils stacked and wound around a core of a transformer.

  Conventionally, in a transformer in which a plurality of coils are wound around a core, as a method of increasing the coupling degree and reducing the leakage magnetic flux, the coupling degree is increased by winding the coils connected to different taps alternately. A method of increasing the number has been proposed (see, for example, Patent Document 1).

JP 2001-237126 A

  However, according to the above-described conventional technique, in the winding structure in which coils connected to different taps are alternately stacked and wound, the coils that are alternately stacked and wound are connected to each other by using parallel multi-core wires. When winding is performed in a typical manner, the winding width of the coil becomes large, and there is a problem that the occupied volume ratio is reduced because the coil cannot be efficiently stored in the winding space in the core.

  Further, in a winding structure in which coils connected to different taps are alternately stacked, it is not easy to reduce the surge voltage while maintaining a high degree of coupling.

  The present invention has been made in view of the above, and it is possible to obtain a transformer capable of increasing the degree of coupling, reducing the leakage magnetic flux, improving the coil occupation volume ratio in the core, and further reducing the surge voltage. With the goal.

  In order to solve the above-described problems and achieve the object, a first transformer of the present invention includes a core and a second coil that is wound around the core and that constitutes one of the primary and secondary sides. A first coil that constitutes the other side of the primary secondary and a plurality of conductive wires connected to the plurality of taps are wound around the core adjacent to the second coil, and the other of the primary and secondary A plurality of conductors connected to the same tap as the plurality of taps to which the first coil is connected are wound around the core adjacent to the opposite side of the first coil across the second coil Each of the first and third coils is wound in a spiral shape from the outer diameter side to the inner diameter side in the first layer. The second layer adjacent to the first layer is formed by being spirally wound from the inner diameter side toward the outer diameter side.

  According to the present invention, the first coil and the third coil connected to the same tap are alternately overlapped and wound so as to sandwich the second coil connected to a different tap. The first and third coils are wound in a spiral shape from the outer diameter side to the inner diameter side in the first layer, and the second coil adjacent to the first layer is wound on the first and third coils. In this layer, the volume occupied in the core is improved by spirally winding from the inner diameter side to the outer diameter side, and a plurality of coils formed of parallel multi-core wires are combined to produce a surge voltage Is reduced.

  Further, the second transformer of the present invention includes a first transformer and a third coil formed in an annular shape having a center hole by winding a plurality of conductive wires arranged in parallel in the first transformer, and a plate-like The second coil formed in a one-turn structure with the conductor formed in the center hole is held in the core by inserting the leg portion of the core into the center hole.

  According to the present invention, the first and third coils formed in an annular shape by winding a plurality of conductive wires arranged in parallel, and the plate-shaped conductor formed in the one-turn structure with the center hole formed. Since the two coils are respectively held by the core by inserting the leg portion of the core into the center hole, the insulation between the core and the coil can be air-insulated, and a bobbin is not required.

  Furthermore, the third transformer of the present invention is characterized in that, in the second transformer, a terminal disposed around the core and connected to the lead wire of the coil extends in the axial direction of the leg portion.

  According to the present invention, the lead portion extending from the coil wound around the leg portion can be drawn on the same plane as the winding plane of the coil and connected to the terminal.

  According to the first transformer of the present invention, it is possible to obtain a transformer capable of increasing the degree of coupling and reducing the magnetic flux leakage, improving the coil occupation volume ratio in the core, and further reducing the surge voltage.

  According to the second transformer of the present invention, a bobbin-less structure can be achieved, so that a reduction in height can be achieved.

  According to the third transformer of the present invention, it is easy to connect the lead portion of the coil to the terminal.

  Embodiments of a transformer according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment)
FIG. 1 is a perspective view showing an appearance of an embodiment of a transformer according to the present invention. The transformer 80 includes an EI type core 10 configured by abutting the E type part 11 and the I type part 12, and a plurality of windings wound around a middle leg part formed at the center of the E type part 11 of the core 10. A coil 20 (wire winding coil and metal plate winding coil, which will be described later), a terminal pedestal 30 that is substantially flat and arranged around the core 10, and a plurality of bars that are erected on the edge of the terminal pedestal 30 Terminal 40.

  FIG. 2 is a perspective view of an intermediate assembly 79 including the core 10, the terminal pedestal 30, and the terminals 40. The core 10 is composed of an E-shaped portion 11 and a flat I-shaped portion 12 that are substantially E-shaped, and is formed of a magnetic member such as ferrite or a dust core. The E-shaped part 11 includes a columnar middle leg part 11a, a pair of rectangular side leg parts 11b, and a connecting part 11c that connects the middle leg part 11a and the two side leg parts 11b. Then, the E-shaped part 11 and the I-shaped part 12 are made to face each other so that the middle leg part 11a is placed inside the rectangular frame-shaped part composed of the side leg part 11b, the connecting part 11c, and the I-shaped part 12. The provided core 10 is configured.

  The terminal pedestal 30 is made of an inexpensive material such as a glass epoxy plate, has a substantially rectangular flat plate shape, and has a rectangular engagement hole at the center. This engagement hole has the same shape as the outer peripheral shape of the E-shaped portion 11. The terminal pedestal 30 is fitted to the core 10 by inserting the E-shaped portion 11 into the engagement hole in the axial direction of the middle leg portion 11a. After the terminal pedestal 30 is fitted to the core 10, both ends are fixed with an adhesive 18. The terminal base 30 attached to the core 10 in this way surrounds the core 10 so as to cross both opposing openings formed in the rectangular frame-shaped portion of the core 10. In addition, reliefs 30b are provided at the four corners of the engagement holes so that the core 10 can be easily inserted.

  A plurality of terminals 40 are erected on the edge of two sides facing the opening of the core 10 of the terminal base 30. Eight terminals 40 (T1 to T8) are erected along the side at one edge. Three terminals 40 (T9 to T11) are provided upright along the side at the opposite edge. A plurality of coils 20 (FIG. 1) formed in an annular shape on the outside are wound around the intermediate assembly 79 thus configured with a bobbin-less structure with the center hole inserted into the middle leg portion 11a. An air layer for insulation is formed between the middle leg portion 11 a and each coil 20. Each terminal 40 is connected to a lead portion (lead wire) drawn from each coil 20.

  FIG. 3 is a perspective view showing a state where a coil is wound around the core 10. FIG. 4 is a front view of the wire-wound coil according to the present embodiment. FIG. 5 is an equivalent circuit of the transformer 80 of the present embodiment. The coil 20 of FIG. 1 demonstrated previously is comprised by the eight coils 21-28 shown by FIG. Of these eight coils, the two coils 23 and 26 are formed in a ring shape by a parallel two-core wire in which a copper wire (conductive wire) covered with an enamel insulating layer is formed in a band shape and is α-turned multiple times. This is a coil of the wire winding type (first and third coils). On the other hand, among the eight coils, the remaining six coils 21, 22, 24, 25, 27, and 28 are metal plate winding type in which a plate-like conductor is formed in a one-turn structure with a center hole formed. Coil (second coil). Each of the coils 21 to 28 is wound so that the center hole is inserted into the middle leg portion 11a of the core 10 and stacked.

  The wire-wound coils 23 and 26 are formed by, for example, winding a copper wire around a predetermined winding frame and then removing it from the winding frame (FIG. 4). The metal plate winding type coils 21, 22, 24, 25, 27, 28 are formed, for example, by punching a thin plate metal by press working. At this time, both types of coils are formed such that the center hole diameter is larger than the diameter of the middle leg portion 11a. When each coil formed in this manner is mounted (wound) on the core 10, a gap having a predetermined width is formed between the middle leg portion 11a and the coil.

  Each of the coils 21 to 28 wound around the core 10 is connected to each other via the terminal 40 by connecting a lead portion (lead wire) to the terminal 40. The metal plate winding type coil 21 has two lead portions connected to terminals T6 and T7. The metal plate winding type coil 22 has a lead portion connected to the terminals T1 and T2. In the wire-wound coil 23, two lead wires at the beginning of winding are connected to the terminals T10 and T11, and two lead wires at the end of winding are connected to the terminals T9 and T10.

  Further, the metal plate winding type coil 24 has two lead portions connected to the terminals T5 and T6. The metal plate winding type coil 25 has a lead portion connected to the terminals T2 and T3. In the wire-wound coil 26, two lead wires at the beginning of winding are connected to the terminals T10 and T11, and two lead wires at the end of winding are connected to the terminals T9 and T10. The metal plate winding type coil 27 has two lead portions connected to terminals T4 and T5. The metal plate winding type coil 28 has a lead portion connected to the terminals T3 and T4. The coils 21 to 28 are connected in this way to form an equivalent circuit shown in FIG. Two adjacent terminals constitute a tap.

  Insulating paper (insulating members) 51 to 57 that are sandwiched between the plurality of stacked coils 21 to 28 to insulate the coils are provided. The insulating papers 51 to 57 have a rectangular sheet shape, are made of resin, have high flexibility, and have a central hole having the same shape as the cross section of the middle leg portion 11a in the central portion. And the middle leg part 11a is inserted in a center hole, and it each pinches | interposes and arrange | positions between two coils adjacent to the lamination direction.

  Next, the characteristics of how to wind the wire-wound coils 23 and 26 of the present embodiment and how to combine the coils will be described. Since the above-described transformer 80 has a complicated configuration, it will be described using a simplified structure for convenience of explanation. FIG. 6 is an equivalent circuit of a transformer simplified for explanation. FIG. 7 is a schematic diagram showing the state of the stacked coils when the coils are combined to form the equivalent circuit of FIG. 6 as in this embodiment. FIG. 8 is a schematic diagram showing a state of stacked coils when the equivalent circuit of FIG. 6 is used without combining the coils shown in FIG.

  In FIG. 7, coils 61, 63, 65 are metal plate winding type coils (second coils) whose lead portions are connected to terminals E, F, and the above-described metal plate winding type coils 21, 22, 24, The same structure as 25, 27, 28 is formed. The coils 62 and 64 are wire winding coils (first and third coils) in which lead wires are connected to the terminals A, B, C and D, and have the same structure as the wire winding coils 23 and 26 described above. Is made. Each coil is wound around the middle leg portion 11a of the EI type core 10 in the order shown in FIG. That is, the coils connected to the different taps are wound alternately on top of each other so that the wire winding coils 62 and 64 sandwich the metal plate winding coil 63.

  FIG. 9 is a schematic view showing a state in which the wire wound coil of the present embodiment is wound. FIG. 10 is a schematic diagram showing a winding method other than the α winding shown in FIG. In the figure, (a) shows the coil viewed from above, (b) shows the coil viewed from the lead wire side, and (c) shows the coil viewed from the side. Further, (D) in the figure shows a state where the E-type part 11 of the core is viewed from above, and (E) shows a state where the E-type part 11 is viewed from the front side.

  In FIG. 9, the coil 62 is formed by winding two parallel core wires (parallel multi-core wires) formed in a strip shape in two layers as shown in FIGS. Then, winding is started from the left side in the figure, the first layer is wound in a spiral shape from the outer diameter side to the inner diameter side while keeping the parallel lines horizontal, and the second week which is the innermost circumference is finished. It moves to the lower second layer and is wound in a spiral shape from the inner diameter side to the outer diameter side. Then, the two lead wires at the beginning of winding are connected to terminal A and terminal B, the lead wire at the end of winding (corresponding to terminal A) is connected to terminal B, and the lead wire (corresponding to terminal C) is connected to terminal B. It is connected to the. The coil 64 is also wound in the same shape and then connected to the terminals A, B, C, and D in the same manner. In this way, the coil 62 and the coil 64 are combined via the terminals. The coils 62 and 64 of the present embodiment are formed by winding parallel two-core wires, but may be parallel three-core wires, parallel four-core wires or more parallel multi-core wires. Furthermore, the coils 62 and 64 are not limited to parallel multi-core wires, and may be formed by winding a plurality of conductive wires arranged in parallel.

  On the other hand, in FIG. 10, the coil 72 starts to be wound from the left side in the drawing, is wound in a spiral shape from the outer diameter side to the inner diameter side in the first layer, and finishes the third week that is the innermost circumference. It is drawn through below the first layer. The two lead wires at the beginning of winding are connected to the terminal A, and the two lead wires at the end of winding are connected to the terminal B. After the coil 74 is wound in the same shape, the two lead wires at the beginning of winding are connected to the terminal C, and the two lead wires at the end of winding are connected to the terminal D.

  FIG. 11 is a diagram showing a state in which the surge voltage generated in the transformer having the structure shown in FIG. 7 is measured with an oscilloscope. FIG. 12 is a diagram showing how the surge voltage generated in the transformer having the structure shown in FIG. 8 is measured with an oscilloscope. In both figures, the surge voltage of each element when the terminals E, F side is used as the primary side and the terminals A, B, C, D side as the secondary side in the equivalent circuit shown in FIG. 6 is measured. Two waveforms (S) and (S) on the upper side (plus side) in the figure show the surge voltage generated on the secondary side, and two waveforms (S) and (C) on the lower side (minus side) in the figure. Indicates a surge voltage generated on the primary side.

  The maximum values of the waveform (S) and the waveform (S) in FIG. 11 were 84.4 V and 82.8 V, whereas the maximum value of the waveform (S) and the waveform (S) in FIG. .3V and 92.2V. In addition, the minimum values of the waveform (S) and the waveform (C) in FIG. 11 were −118.8 V and −114.1 V, whereas the minimum values of the waveform (S) and the waveform (C) in FIG. The values were -132.8V and -151.6V. In other words, the surge voltage can be suppressed by using the α-wound wire-wound coils 23 and 26 combined as shown in FIGS. 7 and 9 as in the present embodiment.

  As described above, in the transformer 80 of the present embodiment, the core 10 and one of the primary and secondary sides are configured, the second coil 63 wound around the core, and the primary and secondary The first coil 62 that configures the other side and the plurality of conductors connected to the plurality of taps are wound around the core adjacent to the second coil 63 and the other side of the primary and secondary sides A plurality of conductive wires connected to the same tap as the plurality of taps to which the first coil 62 is connected are wound around the core adjacent to the opposite side of the first coil 62 with the second coil 63 interposed therebetween. The third coil 64 is provided. The first coil 62 and the third coil 64 are each formed by winding a plurality of conductive wires arranged in parallel in a spiral shape from the outer diameter side to the inner diameter side in the first layer. Is wound in a spiral shape from the inner diameter side to the outer diameter side in a second layer adjacent to the outer layer. Therefore, the degree of coupling is increased by winding coils connected to different taps alternately, and the volume occupied in the core is improved by winding the coils in a predetermined manner using two parallel core wires. Furthermore, the surge voltage is reduced by combining a plurality of coils formed of parallel two-core wires.

  Furthermore, the first coils 23 and 26 formed in an annular shape having a center hole by winding a parallel two-core wire, and the second coil formed in a one-turn structure with a plate-like conductor formed in the center hole. The coils 21, 22, 24, 25, 27, and 28 are respectively held by the core 10 by inserting the middle leg portion 11 a of the core 10 into the center holes. Can be air-insulated, and no bobbin is required, and a bobbin-less structure can be achieved.

  Since the terminal 40 extends in the axial direction of the middle leg portion 11a, the lead portion extending from the coils 21 to 28 can be drawn on the same plane as the winding plane of the coils 21 to 28 and connected to the terminal 40, The lead portion can be easily connected, and the cross connection between the coils 21 to 28 on the terminal 40 is facilitated.

  The transformer according to the present invention is suitable for a transformer mounted on a switching power source such as a power module power source or an on-board power source.

It is a perspective view which shows the external appearance of embodiment of the transformer concerning this invention. It is a perspective view of the intermediate assembly which consists of a core, a terminal base, and a terminal. It is a perspective view which shows a mode that a coil is wound by the core. It is a front view of the wire-wound type coil of the present embodiment. It is a figure which shows the equivalent circuit of the transformer of this Embodiment. It is a figure which shows the equivalent circuit of the transformer simplified for description. It is a schematic diagram which shows the mode of the laminated | stacked coil in the case of combining a coil like this Embodiment and setting it as the equivalent circuit of FIG. It is a schematic diagram which shows the mode of the laminated | stacked coil in the case of setting it as the equivalent circuit of FIG. 6 without combining the coil shown compared with FIG. It is a schematic diagram which shows a mode that the wire wound coil of this Embodiment is wound. It is a schematic diagram which shows the mode of the winding method which is not (alpha) winding shown compared with FIG. It is a figure which shows a mode that the surge voltage which generate | occur | produces in the transformer of the structure shown in FIG. 7 was measured with the oscilloscope. It is a figure which shows a mode that the surge voltage which generate | occur | produces in the transformer of the structure shown in FIG. 8 was measured with the oscilloscope.

Explanation of symbols

10 Core 11 E-type part 11a Middle leg part (leg part)
11b side leg portion 11c connecting portion 12 I-type portion 18 adhesive 20 coil 21, 22, 24, 25, 27, 28 (metal plate winding type) coil (second coil)
23, 26 (wire winding type) coil (first and third coils)
30 terminal pedestal 40 terminal 51-57 insulating paper 61, 63, 65, 71, 73, 75 (metal plate winding type) coil (second coil)
62, 64, 72, 74 (wire winding type) coil (first and third coils)
79 Intermediate assembly 80 Transformer

Claims (3)

The core,
A second coil that constitutes one of the primary and secondary sides and is wound around the core;
A first coil that constitutes the other side of the primary and secondary, and a plurality of conductors connected to a plurality of taps are wound around the core adjacent to the second coil;
A plurality of conductors constituting the other side of the primary and secondary sides and connected to the same tap as the plurality of taps to which the first coil is connected are opposite to the first coil across the second coil. A third coil wound around the core adjacent to the side,
In the first and third coils, a plurality of parallel wires are wound in a spiral shape from the outer diameter side to the inner diameter side in the first layer, and the second coil is adjacent to the first layer. A transformer characterized in that it is formed by spirally winding from the inner diameter side to the outer diameter side. The first and third coils formed in an annular shape having a center hole by winding the plurality of conductive wires arranged in parallel and a plate-like conductor are formed in a one-turn structure by opening the center hole. The transformer according to claim 1, wherein the second coil is held by the core by inserting a leg portion of the core into the center hole. 3. The transformer according to claim 2, wherein a terminal disposed around the core and connected to a lead wire of the coil extends in an axial direction of the leg portion.

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