Transformer

Abstract

To reduce resistance losses and iron losses.SOLUTION: A transformer according to an embodiment of the present invention receives AC power from a power supply-side circuit, transforms voltages and currents by electromagnetic induction effect, and supplies AC power of the same frequency to a load-side circuit. The transformer comprises: a primary winding wire that is connected to the power supply-side circuit; and a secondary winding wire that is connected to the load-side circuit. The transformer further comprises a plurality of cylindrical iron cores interlinking with the primary winding wire and the secondary winding wire. The primary winding wire has a first wiring wire wound around an annular bobbin. The secondary winding wire has a second wiring wire provided inside the first winding wire, a third winding wire provided inside the second winding wire, a fourth winding wire provided outside the first winding wire, and a fifth winding wire provided outside the fourth winding wire. The second winding wire and the third winding wire are formed of mutually different electric wires, respectively. The fourth winding wire and the fifth winding wire are formed of mutually different electric wires, respectively. A width of the third winding wire is narrower than a width of the second winding wire. A width of the fifth winding wire is narrower than a width of the fourth winding wire.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a transformer. [Background technology]

[0002] Transformers are used for the purpose of voltage transformation or current transformation.

[0003] The transformer described in Patent Document 1 includes a first coil. The transformer also includes a second coil coaxially arranged inside the first coil. The transformer also includes a third coil coaxially arranged outside the first coil. The transformer also includes a single bobbin that is arranged between the first coil and the second coil and between the first coil and the third coil and holds the first coil. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-27104 Summary of the Invention [Problem to be solved by the invention]

[0005] Resistance loss and iron loss, which reduce the efficiency of a transformer, are best kept as small as possible. Resistance loss is the power loss that occurs when current flows through a conductor. Iron loss is the loss that occurs when the magnetic flux passing through the iron core fluctuates periodically, and is the sum of hysteresis loss and eddy current loss.

[0006] In the transformer described in Patent Document 1, the first coil, the second coil, the third coil and the bobbin have rectangular cross-sectional shapes, and the iron core has a circular cross-sectional shape, resulting in a large gap between the iron core and the coil, and large resistance loss and iron loss. [Means for solving the problem]

[0007] An aspect of the present invention is a transformer that receives AC power from a power supply circuit, transforms the voltage and current by electromagnetic induction, and supplies AC power of the same frequency to a load circuit. The transformer has a primary winding connected to the power supply circuit. The transformer has a secondary winding connected to the load circuit. The transformer has a plurality of cylindrical iron cores that are linked to the primary winding and the secondary winding. The primary winding has a first winding wound around an annular bobbin. The secondary winding has a second winding provided inside the first winding, a third winding provided inside the second winding, a fourth winding provided outside the first winding, and a fifth winding provided outside the fourth winding. The second winding and the third winding are formed from different electric wires. The fourth winding and the fifth winding are formed from different electric wires. The width of the third winding is narrower than the width of the second winding. The width of the fifth winding is narrower than the width of the fourth winding. [Brief description of the drawings]

[0008]

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Figure 21

[0009] The present invention will be described below through the embodiments of the invention, but the following embodiments do not limit the invention described in the claims. In addition, all of the combinations of features described in the embodiments are not necessarily essential to the solution of the invention.

[0010] FIG. 1 is a perspective view showing an example of a transformer 100.

[0011] The transformer 100 is a device that receives AC power from a power supply circuit, transforms the voltage and current by electromagnetic induction, and supplies AC power of the same frequency to a load circuit. The transformer 100 includes a primary winding 110, a secondary winding 120, and two iron cores 130. For example, the transformer 100 is an oil-immersed transformer in which the primary winding 110, the secondary winding 120, and the iron cores 130 are immersed in transformer insulating oil, and the transformer 100 utilizes the electrical insulating and cooling effects of the transformer insulating oil.

[0012] The primary winding 110 is a winding that is connected to a circuit on the power supply side.

[0013] The secondary winding 120 is a winding that is connected to a circuit on the load side.

[0014] The iron core 130 is cylindrical and is a component that is linked to the primary winding 110 and the secondary winding 120. In other words, the transformer 100 is a shell-type transformer in which multiple independent magnetic circuits are linked to one electric circuit. The iron core 130 is provided with the primary winding 110 and the secondary winding 120 sandwiching a cover 140 therebetween. The cover 140 is a cylindrical component that surrounds the primary winding 110 and the secondary winding 120.

[0015] FIG. 2 is a front view showing an example of the transformer 100 with the iron core 130 and the cover 140 removed.

[0016] The primary winding 110 has a first winding 111 .

[0017] The first winding 111 is a winding that is wound around an annular bobbin 150. The bobbin 150 is a winding frame for winding an electric wire.

[0018] The secondary winding 120 includes a second winding 122, a third winding 123, a fourth winding 124, and a fifth winding 125.

[0019] The second winding 122 is a winding provided inside the first winding 111. The second winding 122 is formed by winding a flat electric wire in the same direction as the width direction of the first winding 111 so that the surface of the electric wire is parallel to the height direction of the first winding 111. The second winding 122 is formed from an electric wire separate from the third winding 123.

[0020] The third winding 123 is a winding provided inside the second winding 122. The third winding 123 is formed by winding a flat electric wire in the same direction as the width direction of the first winding 111 so that the surface of the electric wire is parallel to the height direction of the first winding 111. The third winding 123 is formed from an electric wire separate from the second winding 122.

[0021] The fourth winding 124 is a winding provided on the outside of the first winding 111. The fourth winding 124 is formed by winding a flat electric wire in the same direction as the width direction of the first winding 111 so that the surface of the electric wire is parallel to the height direction of the first winding 111. The fourth winding 124 is formed from an electric wire separate from the fifth winding 125.

[0022] The fifth winding 125 is a winding provided on the outside of the fourth winding 124. The fifth winding 125 is formed by winding a flat electric wire in the same direction as the width direction of the first winding 111 so that the surface of the electric wire is parallel to the height direction of the first winding 111. The fifth winding 125 is formed from an electric wire separate from the fourth winding 124.

[0023] Fig. 3 is a diagram showing an example of a cross section taken along line A-A' in Fig. 2. The width BW of the bobbin 150, the width WW2 of the second winding 122, the width WW3 of the third winding 123, the width WW4 of the fourth winding 124, and the width WW5 of the fifth winding 125 shown in Fig. 3 are examples. The number of turns of the second winding 122, the number of turns of the third winding 123, the number of turns of the fourth winding 124, and the number of turns of the fifth winding 125 shown in Fig. 3 are examples.

[0024] The width BW of the bobbin 150 is wider than the width WW2 of the second winding 122. Also, the width BW of the bobbin 150 is wider than the width WW3 of the third winding 123. Also, the width BW of the bobbin 150 is wider than the width WW4 of the fourth winding 124. Also, the width BW of the bobbin 150 is wider than the width WW5 of the fifth winding 125.

[0025] The width WW2 of the second winding 122 is narrower than the width BW of the bobbin 150. Also, the width WW2 of the second winding 122 is wider than the width WW3 of the third winding 123. Also, the width WW2 of the second winding 122 is the same width as the width WW4 of the fourth winding 124. Also, the width WW2 of the second winding 122 is wider than the width WW5 of the fifth winding 125.

[0026] The width WW3 of the third winding 123 is narrower than the width BW of the bobbin 150. Also, the width WW3 of the third winding 123 is narrower than the width WW2 of the second winding 122. Also, the width WW3 of the third winding 123 is narrower than the width WW4 of the fourth winding 124. Also, the width WW3 of the third winding 123 is the same width as the width WW5 of the fifth winding 125.

[0027] The width WW4 of the fourth winding 124 is narrower than the width BW of the bobbin 150. Also, the width WW4 of the fourth winding 124 is the same width as the width WW2 of the second winding 122. Also, the width WW4 of the fourth winding 124 is wider than the width WW3 of the third winding 123. Also, the width WW4 of the fourth winding 124 is wider than the width WW5 of the fifth winding 125.

[0028] The width WW5 of the fifth winding 125 is narrower than the width BW of the bobbin 150. Also, the width WW5 of the fifth winding 125 is narrower than the width WW2 of the second winding 122. Also, the width WW5 of the fifth winding 125 is the same width as the width WW3 of the third winding. Also, the width WW5 of the fifth winding 125 is narrower than the width WW4 of the fourth winding 124.

[0029] In the width direction, the number of turns of the third winding 123 is less than the number of turns of the second winding 122. In the example shown in FIG. 3, the number of turns of the second winding 122 is "26". In the example shown in FIG. 3, the number of turns of the third winding 123 is "10".

[0030] In the width direction, the number of turns of the fifth winding 125 is smaller than the number of turns of the fourth winding 124. In the example shown in Fig. 3, the number of turns of the fourth winding 124 is "26". In the example shown in Fig. 3, the number of turns of the fifth winding 125 is "10".

[0031] In the width direction, the number of turns of the second winding 122 is the same as the number of turns of the fourth winding 124. In the example shown in Fig. 3, the number of turns of the second winding 122 and the number of turns of the fourth winding 124 are both "26".

[0032] In the width direction, the number of turns of the third winding 123 is the same as the number of turns of the fifth winding 125. In the example shown in Fig. 3, the number of turns of the third winding 123 and the number of turns of the fifth winding 125 are both "10".

[0033] The number of turns of the second winding 122 may be more than the number of turns of the third winding 123 and may be the same as the number of turns of the fourth winding 124, and may be more or less than "26".

[0034] The number of turns of the third winding 123 may be less than the number of turns of the second winding 122 and may be the same as the number of turns of the fifth winding 125, and may be less than or more than "10".

[0035] The number of turns of the fourth winding 124 may be greater than the number of turns of the fifth winding 125 and may be the same as the number of turns of the second winding 122, and may be greater or less than "26".

[0036] The number of turns of the fifth winding 125 may be less than the number of turns of the fourth winding 124 and may be the same as the number of turns of the third winding 123, and may be less than or more than "10".

[0037] Fig. 4 is a perspective view showing an example of one end of the second winding 122, the third winding 123, the fourth winding 124, and the fifth winding 125. In Fig. 4, the first winding 111 and the bobbin 150 are not shown in order to clearly show one end of the second winding 122, the third winding 123, the fourth winding 124, and the fifth winding 125.

[0038] The electric wire EW2A extending from the first end 122A of the second winding 122 is bent toward the front at the first end 122A. Similarly, the electric wire EW3A extending from the first end 123A of the third winding 123 is bent toward the front at the first end 123A. Similarly, the electric wire EW4A extending from the first end 124A of the fourth winding 124 is bent toward the front at the first end 124A. Similarly, the electric wire EW5A extending from the first end 125A of the fifth winding 125 is bent toward the front at the first end 125A.

[0039] The electric wires EW2A and EW5A are connected by a connecting member JE1. Similarly, the electric wires EW3A and EW4A are connected by a connecting member JE2.

[0040] Fig. 5 is a perspective view showing an example of the other ends of the second winding 122, the third winding 123, the fourth winding 124, and the fifth winding 125. In order to clearly show the other ends of the second winding 122, the third winding 123, the fourth winding 124, and the fifth winding 125, Fig. 5 does not show the first winding 111 and the bobbin 150.

[0041] The electric wire EW2B extending from the second end 122B of the second winding 122 is bent toward the rear surface at the second end 122B. Similarly, the electric wire EW3B extending from the second end 123B of the third winding 123 is bent toward the rear surface at the second end 123B. Similarly, the electric wire EW4B extending from the second end 124B of the fourth winding 124 is bent toward the rear surface at the second end 124B. Similarly, the electric wire EW5B extending from the second end 125B of the fifth winding 125 is bent toward the rear surface at the second end 125B.

[0042] The electric wire EW3B is connected to the connection terminal CT1. The connection terminal CT1 is connected to a first voltage line of the load side circuit.

[0043] The electric wire EW5B is connected to the connection terminal CT2. The connection terminal CT2 is connected to the second voltage line of the load side circuit.

[0044] The electric wire EW2B and the electric wire EW4B are connected to a connection terminal CT3. The connection terminal CT3 is connected to the neutral line of the load side circuit.

[0045] As described above, the transformer 100 is a device that receives AC power from a power supply circuit, transforms the voltage and current by electromagnetic induction, and supplies AC power of the same frequency to a load circuit. The transformer 100 includes a primary winding 110 connected to the power supply circuit. The transformer 100 also includes a secondary winding 120 connected to the load circuit. The transformer 100 also includes two cylindrical iron cores 130 that are interlinked with the primary winding 110 and the secondary winding 120. The primary winding 110 includes a first winding 111 wound around an annular bobbin 150. The secondary winding 120 includes a second winding 122 provided inside the first winding 111 and a third winding 123 provided inside the second winding 122. The secondary winding 120 also has a fourth winding 124 provided outside the first winding 111 and a fifth winding 125 provided outside the fourth winding 124. The second winding 122 and the third winding 123 are formed of different electric wires. The fourth winding 124 and the fifth winding 125 are formed of different electric wires. The width WW3 of the third winding 123 is narrower than the width WW2 of the second winding 122. The width WW5 of the fifth winding 125 is narrower than the width WW4 of the fourth winding 124. With this configuration, the cross-sectional shape of each winding and the bobbin 150 of the transformer 100 is aligned with the circular cross-sectional shape of the iron core 130, so that the gap between the iron core 130 and each winding is small, and resistance loss and iron loss can be suppressed.

[0046] Furthermore, the width WW3 of the third winding 123 and the width WW5 of the fifth winding 125 are narrower than the width BW of the bobbin 150. With this configuration, in the transformer 100, the cross-sectional shapes of the windings and bobbin 150 are more likely to conform to the circular cross-sectional shape of the iron core 130, making it possible to reduce the gap between the iron core 130 and each winding, and more efficiently suppressing resistance loss and iron loss.

[0047] Furthermore, the width WW2 of the second winding 122 and the width WW4 of the fourth winding 124 are narrower than the width BW of the bobbin 150. With this configuration, in the transformer 100, the cross-sectional shapes of the windings and bobbin 150 are more likely to conform to the circular cross-sectional shape of the iron core 130, making it possible to reduce the gap between the iron core 130 and each winding, and more efficiently suppressing resistance loss and iron loss.

[0048] Furthermore, width WW2 of second winding 122 is the same as width WW4 of fourth winding 124. Width WW3 of third winding 123 is the same as width WW5 of fifth winding 125. With this configuration, in transformer 100, the cross-sectional shapes of each winding and bobbin 150 are more likely to conform to the circular cross-sectional shape of iron core 130, the gap between iron core 130 and each winding can be made smaller, and resistance loss and iron loss can be more efficiently suppressed.

[0049] In addition, in the width direction, the number of turns of the third winding 123 is smaller than the number of turns of the second winding 122. In the width direction, the number of turns of the fifth winding 125 is smaller than the number of turns of the fourth winding 124. With this configuration, in the transformer 100, the cross-sectional shape of each winding and bobbin 150 is more likely to conform to the circular cross-sectional shape of the iron core 130, the gap between the iron core 130 and each winding can be made smaller, and resistance loss and iron loss can be more efficiently suppressed.

[0050] In addition, in the width direction, the number of turns of the second winding 122 is the same as the number of turns of the fourth winding 124. In the width direction, the number of turns of the third winding 123 is the same as the number of turns of the fifth winding 125. With this configuration, in the transformer 100, the cross-sectional shape of each winding and bobbin 150 is more likely to conform to the circular cross-sectional shape of the iron core 130, the gap between the iron core 130 and each winding can be made smaller, and resistance loss and iron loss can be more efficiently suppressed.

[0051] Additionally, a first end 122A of the second winding 122 is connected to a first end 125A of the fifth winding 125. A first end 123A of the third winding 123 is connected to a first end 124A of the fourth winding 124. According to this configuration, the secondary winding 120 of the transformer 100 is formed by two sets of windings combining a wide winding and a narrow winding.

[0052] Also, the second end 123B of the third winding 123 is connected to a first voltage line of the load side circuit. The second end 125B of the fifth winding 125 is connected to a second voltage line of the load side circuit. The second end 122B of the second winding 122 and the second end 124B of the fourth winding 124 are connected to the neutral line of the load side circuit. With this configuration, the transformer 100 can supply AC power to a single-phase three-wire load side circuit.

[0053] Moreover, the second winding 122, the third winding 123, the fourth winding 124, and the fifth winding 125 are formed of flat electric wires. With this configuration, the secondary coil of the transformer 100 can be formed without using a winding form for the secondary coil.

[0054] The primary winding 110, the secondary winding 120, and the iron core 130 are immersed in transformer insulating oil. With this configuration, the transformer 100 can utilize the insulating and cooling effects of the oil.

[0055] Fig. 6 is a perspective view showing an example of the bobbin 150. Fig. 7 is a side view showing an example of the bobbin 150. Fig. 8 is a perspective view showing an example of the bobbin 150 with the first winding 111 wound thereon. Fig. 9 is a side view showing an example of the bobbin 150 with the first winding 111 wound thereon.

[0056] The bobbin 150 has two flange portions 151 and a plurality of partition portions 152. In the example shown in Fig. 6 and Fig. 7, the bobbin 150 has five partition portions 152. The number of partition portions 152 shown in Fig. 6 and Fig. 7 is just an example. The number of partition portions 152 may be one or more, and may be more or less than five.

[0057] The flanges 151 are provided on both ends of the bobbin 150 in the width direction, and are members for preventing the first winding 111 from slipping off the bobbin 150.

[0058] The partitions 152 are members that divide the outer periphery of the bobbin 150 into a plurality of winding regions WR. The outer periphery of the bobbin 150 is divided by the partitions 152 into winding regions WR whose number is one more than the number of the partitions 152. In the example shown in FIG. 7, the outer periphery of the bobbin 150 is divided into six winding regions WR by five partitions 152. The first winding 111 is wound in the winding region WR on the outer periphery of the bobbin 150. That is, the partitions 152 divide the first winding 111 on the outer periphery of the bobbin 150.

[0059] The flange portion 151 includes a plurality of protruding portions 151A and a support portion 151B. In the example shown in Fig. 6 and Fig. 8, the flange portion 151 includes twelve protruding portions 151A. The number of protruding portions 151A shown in Fig. 6 and Fig. 8 is an example. The flange portion 151 only needs to include a plurality of protruding portions 151A, and may include fewer than twelve protruding portions 151A, or may include more than twelve protruding portions 151A.

[0060] The partition portion 152 includes a plurality of protrusions 152A and a support portion 152B. In the example shown in Fig. 6 and Fig. 8, the partition portion 152 is illustrated at an angle in which some of the protrusions 152A are not visible, but includes 12 protrusions 152A. The number of protrusions 152A shown in Fig. 6 and Fig. 8 is an example. The partition portion 152 only needs to include a plurality of protrusions 152A, and may include fewer than 12 protrusions 152A or may include more than 12 protrusions 152A.

[0061] Protrusion 151A is a rod-shaped portion protruding outward from flange 151. The multiple protrusions 151A are spaced apart from one another in the winding direction of first winding 111. Similarly, protrusion 152A is a rod-shaped portion protruding outward from partition 152. The multiple protrusions 152A are spaced apart from one another in the winding direction of first winding 111. Protrusion 152A shown in FIGS. 6 to 9 is provided at a position overlapping with protrusion 151A in front view. Tips of protrusion 151A and protrusion 152A are located outside the outer circumferential end of first winding 111.

[0062] Support portion 151B is a portion of flange portion 151 that supports protruding portion 151A. Support portion 151B extends in the winding direction of first winding 111 and is provided so as to protrude from the outer periphery of bobbin 150. Similarly, support portion 152B is a portion of partition portion 152 that supports protruding portion 152A. Support portion 152B extends in the winding direction of first winding 111 and is provided so as to protrude from the outer periphery of bobbin 150.

[0063] The first winding 111 separated by the partition 152 is formed of a single electric wire. The electric wire at the end of the first winding 111 wound in the winding region WR straddles the outside of the partition 152 and becomes the start of the first winding 111 wound in the adjacent winding region WR.

[0064] The flange portion 151 includes two protective portions 151C. The protective portions 151C are portions that protect the winding start and winding end portions of the first winding 111. The two protective portions 151C are provided spaced apart from each other in the winding direction of the first winding 111.

[0065] The partition portion 152 includes a guide portion 152C. The guide portion 152C is a portion of the partition portion 152 that guides the first winding 111 that straddles the outer side of the partition portion 152. The guide portion 152C has a sector shape in a front view.

[0066] FIG. 10 is a front view showing an example of the bobbin 150. As shown in FIG.

[0067] The bobbin 150 has a rectangular ring shape with rounded corners 150A when viewed from the front.

[0068] In the example shown in FIG. 10, the protrusions 151A are provided at the corners 150A and the sides 150B in the front view of the bobbin 150. When the protrusions 151A are provided at the corners 150A and the sides 150B as in the example shown in FIG. 10, the number of the protrusions 151A provided at one corner 150A may be greater than the number of the protrusions 151A provided at one side 150B. In the example shown in FIG. 10, the number of the protrusions 151A provided at one corner 150A is two or three. In the example shown in FIG. 10, the number of the protrusions 151A provided at one side 150B is one. The number of the protrusions 151A provided at one corner 150A may be greater than the number of the protrusions 151A provided at one side 150B, and may be less than two or more than three. Furthermore, the number of protruding portions 151A provided on one side portion 150B may be two or more as long as it is smaller than the number of protruding portions 151A provided on one corner portion 150A.

[0069] Similarly, the protrusions 152A are provided at the corners 150A and the sides 150B in a front view of the bobbin 150. The number of the protrusions 152A provided at one corner 150A is greater than the number of the protrusions 152A provided at one side 150B. Although the protrusions 152A are shown at an angle where they are hidden by the protrusions 151A and cannot be seen, the number of the protrusions 152A provided at one corner 150A shown in FIG. 10 is two or three. Although the protrusions 152A are shown at an angle where they are hidden by the protrusions 151A and cannot be seen, the number of the protrusions 152A provided at one side 150B shown in FIG. 10 is one.

[0070] FIG. 11 is a diagram showing an example of the protruding length of the support portion 152B.

[0071] The protruding length of the support portion 152B is set to a length such that the creepage distance CD between the windings of the first winding 111 separated by the partition portion 152 satisfies the insulation distance. The creepage distance CD is the shortest distance of a path along the surface of the bobbin 150 between the first winding 111 on both sides of the partition portion 152 separated by the partition portion 152. The creepage distance CD of the bobbin 150 is a path along the surface of the winding region WR and the surface of the support portion 152B. The insulation distance is a distance such that the first winding 111 on both sides of the partition portion 152 separated by the partition portion 152 are not short-circuited.

[0072] FIG. 12 is a front view showing an example of the guide portion 152C.

[0073] The guide portion 152C includes a notch N1 and an inclined portion S1.

[0074] The notch N1 is a portion where the wire of the first winding 111 that straddles the outside of the partition portion 152 in the guide portion 152C is hung.

[0075] The inclined portion S1 is a portion that guides the electric wire hung in the notch portion N1 in the guide portion 152C to the surface of the winding region WR in the outer circumferential portion.

[0076] As described above, primary winding 110 is wound around the outer periphery of annular bobbin 150. Bobbin 150 has partitions 152 that divide primary winding 110 in the width direction of the outer periphery. Partitions 152 have multiple protrusions 152A that protrude outward. Multiple protrusions 152A are provided spaced apart from each other in the winding direction of primary winding 110. With this configuration, when transformer 100 is used as an oil-filled transformer, air is less likely to remain between primary winding 110 and partitions 152 when evacuation is performed.

[0077] Furthermore, the tips of protrusion 152A and guide portion 152C are located outside the outer circumferential end of primary winding 110. With this configuration, transformer 100 can prevent first winding 111 and fourth winding 124 from contacting each other.

[0078] Moreover, bobbin 150 has a rectangular ring shape with rounded corners 150A. Protrusions 152A are provided at corners 150A of bobbin 150. With this configuration, transformer 100 can prevent first winding 111 from becoming unwound at corners 150A of bobbin 150.

[0079] Moreover, protruding portion 152A is provided on side portion 150B of bobbin 150. With this configuration, transformer 100 can prevent first winding 111 from becoming unbalanced at side portion 150B of bobbin 150.

[0080] Moreover, the number of protrusions 152A provided at one corner 150A is greater than the number of protrusions 152A provided at one side 150B. With this configuration, transformer 100 can prevent air from remaining between primary winding 110 and partition 152 when used as an oil-filled transformer, while preventing collapse of first winding 111.

[0081] Furthermore, the partition 152 includes a support 152B that supports the protruding portion 152A. The support 152B extends in the winding direction of the primary winding 110 and protrudes from the outer periphery. The protruding length of the support 152B is set to a length that makes the creepage distance CD between the turns of the primary winding 110 separated by the partition 152 satisfy the insulation distance. With this configuration, the transformer 100 can effectively prevent air from remaining between the primary winding 110 and the partition 152 by setting the protruding length of the support 152B to a length that makes the creepage distance CD satisfy the insulation distance.

[0082] Moreover, the primary winding 110 separated by the partition 152 is formed of a single electric wire. The partition 152 includes a guide portion 152C that guides the electric wire of the primary winding 110 that straddles the outside of the partition 152. According to this configuration, a worker assembling the transformer 100 can guide the electric wire at the end of the winding of the primary winding 110 wound in the winding region WR as the electric wire that starts winding the primary winding 110 wound in the adjacent winding region WR.

[0083] In addition, the guide portion 152C includes a notch N1 for hanging the electric wire of the primary winding 110 that straddles the outside of the partition portion 152. According to this configuration, a worker assembling the transformer 100 can apply tension to the primary winding 110 that straddles the outside of the partition portion 152.

[0084] In addition, the guide portion 152C includes an inclined portion S1 that guides the electric wire hung in the notch portion N1 to the surface of the outer periphery. With this configuration, a worker assembling the transformer 100 can start winding the primary winding 110 separated by the partition portion 152 from the surface of the outer periphery of the bobbin 150.

[0085] Fig. 13 is a perspective view showing an example of the cover 140 enclosing the first winding 111, the second winding 122, the third winding 123, the fourth winding 124, the fifth winding 125 and the bobbin 150. Fig. 14 is a perspective view showing an example of the cover 140. Fig. 15 is a side view showing an example of the cover 140 when the end side portion 141 is viewed from the front. Fig. 16 is a side view showing an example of the cover 140 when the hinge portion 142 is viewed from the front.

[0086] The cover 140 is made of synthetic resin and includes a pair of end portions 141 and a hinge portion 142.

[0087] End portion 141 is a portion of cover 140 that allows part of cover 140 to be opened and closed while remaining integral. The pair of end portions 141 are fixed to each other by snap-fitting. One end portion 141 has a protrusion 141A for the snap-fitting. The other end portion 141 has a recess 141B for the snap-fitting. Snap-fitting is an assembly method in which protrusion 141A is fitted into and hooked into recess 141B using the elasticity of the material, thereby mechanically fixing the cover 140.

[0088] The hinge portion 142 is a portion that serves as a fulcrum when the pair of end side portions 141 of the cover 140 open.

[0089] FIG. 17 is a plan view showing an example of the cover 140. As shown in FIG.

[0090] The thickness of the hinge portion 142 is thinner than the thickness of other portions of the cover 140. In the example shown in Fig. 17, the hinge portion 142 is formed by reducing the wall thickness.

[0091] Fig. 18 is a perspective view showing an example of cover 140 in a state where a pair of end sides 141 are closed relative to each other. Fig. 19 is a plan view showing an example of cover 140 in a state where a pair of end sides 141 are closed relative to each other.

[0092] The hinge portion 142 is provided at a symmetrical position of the end side portions 141 with respect to the axis AX of the cover 140 when the pair of end side portions 141 are closed.

[0093] FIG. 20 is a front view showing an example of the cover 140 enclosing the first winding 111, the second winding 122, the third winding 123, the fourth winding 124, the fifth winding 125 and the bobbin 150. As shown in FIG.

[0094] The bobbin 150 includes a first restricting portion 153A and a second restricting portion 153B.

[0095] The first restricting portion 153A is a component that restricts the position of one end of the cover 140 in the axial direction. The first restricting portion 153A is provided on the front side and the rear side of the bobbin 150. The front side first restricting portion 153A and the rear side first restricting portion 153A are provided at symmetrical positions in a front view. The cover 140 shown in FIG. 20 is restricted from moving upward in the vertical direction of the drawing by the first restricting portion 153A.

[0096] The second restricting portion 153B is a component that restricts the position of the other end portion in the axial direction of the cover 140. The second restricting portion 153B is provided on the front side and the rear side of the bobbin 150, respectively. The front side second restricting portion 153B and the rear side second restricting portion 153B are provided at symmetrical positions in a front view. The cover 140 shown in FIG. 20 is restricted from moving downward in the up-down direction of the drawing by the second restricting portion 153B.

[0097] The first and second restricting portions 153A and 153B are provided at positions such that the distance from the first restricting portion 153A to the second restricting portion 153B is the same as or slightly longer than the axial length of the cover 140.

[0098] FIG. 21 is a diagram showing an example of a cross section taken along line BB' in FIG.

[0099] The radially inner shape of the cover 140 is a shape that follows the outer shapes of the first winding 111, the second winding 122, the third winding 123, the fourth winding 124, the fifth winding 125 and the bobbin 150.

[0100] As described above, the iron core 130 is provided with the primary winding 110 and the secondary winding 120 sandwiching the cylindrical cover 140 that surrounds the primary winding 110 and the secondary winding 120. The cover 140 has a pair of end sides 141 that allow a portion of the cover to be opened or closed while remaining integrated. With this configuration, the designer of the transformer 100 does not need to make design changes to the cover 140 even if the distance between the two covers 140 changes due to a design change.

[0101] Moreover, the pair of end sides 141 are fixed to each other by snap fitting. According to this configuration, the worker who assembles the transformer 100 can easily attach the cover 140.

[0102] Moreover, cover 140 includes hinge portion 142 that serves as a fulcrum when end portion 141 is opened. With this configuration, a worker assembling transformer 100 can open cover 140 without applying excessive load to cover 140.

[0103] Furthermore, the thickness of hinge portion 142 is thinner than the thickness of other portions of cover 140. With this configuration, it is possible to prevent a load from being applied to portions other than hinge portion 142 when cover 140 is unfolded.

[0104] Moreover, the hinge portion 142 is formed by reducing the thickness of the cover 140. According to this configuration, the hinge portion 142 can be formed in the cover 140 without using metal.

[0105] Furthermore, the hinge portions 142 are provided at symmetrical positions of the end sides 141 with respect to the axis AX of the cover 140 when the pair of end sides 141 are closed. With this configuration, the end sides 141 of the cover 140 can be opened and closed smoothly.

[0106] Moreover, the radially inner shape of the cover 140 is a shape that follows the outer shapes of the primary winding 110 and the secondary winding 120. According to this configuration, when the cover 140 is attached so as to surround the primary winding 110 and the secondary winding 120, the cover 140 is restricted from rotating in the circumferential direction.

[0107] Moreover, the cover 140 is made of synthetic resin. With this configuration, the transformer 100 does not have an unintended magnetic circuit caused by the cover 140.

[0108] Further, bobbin 150 includes a first restricting portion 153A that restricts the position of one end of cover 140 in the axial direction. Bobbin 150 includes a second restricting portion 153B that restricts the position of the other end of cover 140 in the axial direction. With this configuration, cover 140 is restricted from shifting in the axial direction when cover 140 is attached to surround primary winding 110 and secondary winding 120.

[0109] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the embodiments. It is clear to those skilled in the art that various modifications or improvements can be made to the embodiments. It is clear from the description of the claims that such modifications or improvements can also be included in the technical scope of the present invention.

[0110] The protruding portion 152A in the embodiment is provided at a position overlapping the protruding portion 151A in a front view. However, the multiple protruding portions 152A only need to be spaced apart from one another in the winding direction of the first winding 111, and do not have to be provided at a position overlapping the protruding portion 151A in a front view. For example, the multiple protruding portions 152A may be provided at a position not overlapping the protruding portion 151A in a front view. Similarly, the protruding portion 152A of a partition portion 152 may be provided at a position not overlapping the protruding portion 152A of another partition portion 152 in a front view.

[0111] In the embodiment, the rod-shaped protrusion 151A and the rod-shaped protrusion 152A are provided at the corner 150A and the side 150B. However, the protrusion 151A and the protrusion 152A provided at the corner 150A do not have to be rod-shaped. For example, the protrusion 151A and the protrusion 152A provided at the corner 150A may be fan-shaped in a front view.

[0112] Hinge portion 142 in the embodiment is formed by reducing the thickness. However, hinge portion 142 is not limited to being formed by reducing the thickness as long as it serves as a fulcrum when pair of end side portions 141 of cover 140 open. For example, hinge portion 142 may be a hinge made of resin. [Explanation of symbols]

[0113] 100 transformer, 110 primary winding, 111 first winding, 120 secondary winding, 122 second winding, 123 third winding, 124 fourth winding, 125 fifth winding, 130 iron core, 140 cover, 141 end portion, 141A convex portion, 141B concave portion, 142 hinge portion, 150 bobbin, 150A corner portion, 150B side portion, 151 flange portion, 151A protruding portion, 151B supporting portion, 151C protective portion, 152 partition portion, 152A protruding portion, 152B supporting portion, 152C guide portion, 153A first restricting portion, 153B second restricting portion

Claims

1. A transformer that receives AC power from a power supply circuit, transforms the voltage and current by electromagnetic induction, and supplies AC power of the same frequency to a load circuit, A primary winding connected to a power supply circuit; A secondary winding connected to a load circuit; a plurality of cylindrical iron cores interlinked with the primary winding and the secondary winding, The primary winding includes a first winding wound on an annular bobbin, the secondary winding includes a second winding provided inside the first winding, a third winding provided inside the second winding, a fourth winding provided outside the first winding, and a fifth winding provided outside the fourth winding, the second winding and the third winding are formed from different electric wires, the fourth winding and the fifth winding are formed from different electric wires, The width of the third winding is narrower than the width of the second winding, A transformer, wherein the fifth winding has a width smaller than a width of the fourth winding.

2. The transformer of claim 1 , wherein a width of the third winding and a width of the fifth winding are narrower than a width of the bobbin.

3. The transformer of claim 1 , wherein a width of the second winding and a width of the fourth winding are narrower than a width of the bobbin.

4. The width of the second winding is the same as the width of the fourth winding, 2. The transformer of claim 1, wherein the width of the third winding is the same as the width of the fifth winding.

5. In the width direction, the number of turns of the third winding is smaller than the number of turns of the second winding, 2. The transformer according to claim 1, wherein the number of turns of the fifth winding is less than the number of turns of the fourth winding in the width direction.

6. In the width direction, the number of turns of the second winding is the same as the number of turns of the fourth winding, 2. The transformer according to claim 1, wherein the number of turns of the third winding is the same as the number of turns of the fifth winding in the width direction.

7. a first end of the second winding is connected to a first end of the fifth winding; 2. The transformer of claim 1, wherein a first end of the third winding is connected to a first end of the fourth winding.

8. a second end of the third winding is connected to a first voltage line of a load side circuit; a second end of the fifth winding is connected to a second voltage line of a load side circuit; 8. The transformer according to claim 7, wherein the second end of the second winding and the second end of the fourth winding are connected to a neutral line of a load side circuit.

9. 2. The transformer according to claim 1, wherein the second winding, the third winding, the fourth winding, and the fifth winding are formed of flat electric wires.

10. 2. The transformer of claim 1, wherein the primary winding, the secondary winding and the core are immersed in transformer oil.

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