Transformer

Abstract

To provide a transformer capable of reducing impedance and cost.SOLUTION: A transformer 1 includes first coils 3, 4, a second coil 7 coaxially arranged inside the first coils 3, 4, a third coil 6 coaxially arranged on the outside of the first coils 3, 4, and a single bobbin 2 that is arranged between the first coils 3, 4 and the second coil 7, and between the first coils 3, 4 and the third coil 6 and holds the first coils 3, 4.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present technology relates to transformers, including voltage transformers. [Background technology]

[0002] Conventionally, a transformer including an iron core, a primary coil, and a secondary coil has been proposed. The primary coil and the secondary coil are each wound around a bobbin (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-51034 Summary of the Invention [Problem to be solved by the invention]

[0004] To reduce impedance, it is possible to create a triple-coil transformer by placing a secondary coil inside and outside the primary coil, but each coil is held by a bobbin, which increases the cost.

[0005] The present disclosure has been made in consideration of the above circumstances, and has an object to provide a transformer that can reduce impedance and costs. [Means for solving the problem]

[0006] The transformer of the present disclosure comprises a first coil, a second coil coaxially arranged inside the first coil without being held by a bobbin, a third coil coaxially arranged outside the first coil without being held by a bobbin, and a first coil holding bobbin arranged between the first coil and the second coil and between the first coil and the third coil and holding the first coil, wherein the first coil holding bobbin does not hold the second coil and the third coil, and the second coil and the third coil have a structure that holds their own shapes, and the structure is composed of a group of wires made of flat wire or a plurality of round wires that are integrated by restraining them with a band or solidifying them with resin.

[0007] In the present disclosure, one bobbin is used, and the coils are arranged in triplicate, thereby reducing the number of bobbins. Furthermore, the second coil and the third coil retain their own shape even without a bobbin. Therefore, even if the number of bobbins is reduced, a triple coil structure can be realized. Furthermore, by winding the second coil and the third coil with a wire group that integrates a rectangular wire or multiple round wires, the shape of the second coil and the third coil can be maintained without a bobbin.

[0008] The transformer according to the present disclosure includes a retaining cover that covers and retains the inside and outside of the first coil, the second coil, and the third coil.

[0009] In the present disclosure, the first coil, the second coil, and the third coil are integrally held and unitized by the retaining cover.

[0010] The transformer according to the present disclosure includes a spacer disposed between the first coil and the second coil or the third coil.

[0011] In the present disclosure, the spacer ensures a predetermined distance between the first coil and the second coil, or between the first coil and the third coil, thereby insulating them from each other. Effect of the Invention

[0012] In the transformer according to the present disclosure, a single bobbin is used and the coil is arranged in triplicate, thereby reducing the number of bobbins, thereby reducing impedance and cost. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a simplified perspective view of a transformer according to an embodiment. [Diagram 2] FIG. 2 is a simplified exploded view of a transformer. [Diagram 3] 4 is a schematic cross-sectional view of a bobbin, an outer secondary coil, an inner secondary coil, and a retaining cover. FIG. [Figure 4] FIG. 11 is a schematic cross-sectional view of a bobbin, an outer secondary coil, an inner secondary coil, and a retaining cover, the configuration of which is partially modified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] The present invention will be described below with reference to the drawings showing a transformer according to an embodiment. FIG. 1 is a schematic perspective view of a transformer according to an embodiment, and FIG. 2 is a schematic exploded view of the transformer. The transformer 1 includes a rectangular annular resin bobbin 2. A groove extending in the circumferential direction is formed on the outer peripheral surface of the bobbin 2, and the groove is provided around the entire circumference of the bobbin 2. A wall 2a protruding radially outward is formed at the bottom of the groove. The wall 2a extends in the circumferential direction and is provided around the entire circumference of the bobbin 2. A primary coil 3 is wound around one side of the wall 2a, and a primary coil 4 is wound around the other side of the wall 2a. The bobbin 2 holds the primary coils 3 and 4. The primary coils 3 and 4 correspond to the first coil.

[0015] A secondary coil 7 (hereinafter, referred to as the inner secondary coil 7) is provided on the radial inside of the bobbin 2. The radial dimension of the outer circumference of the inner secondary coil 7 corresponds to the radial dimension and axial dimension of the inner circumference of the bobbin 2, and the inner secondary coil 7 fits inside the bobbin 2. The inner secondary coil 7 has a structure that retains its own shape, and can maintain the coil shape even without a retaining mechanism such as a bobbin. The inner secondary coil 7 is made of, for example, a rectangular wire, and is formed by bending the rectangular wire. The inner secondary coil 7 corresponds to the second coil. Instead of the rectangular wire, a wire group in which multiple round wires are integrated may be used. For example, the wire group is created by binding multiple round wires with a band or solidifying them with resin. The wire group can achieve shape retention like the rectangular wire.

[0016] A secondary coil 6 (hereinafter referred to as the outer secondary coil 6) is provided radially outside the bobbin 2. The radial and axial dimensions of the inner circumference of the outer secondary coil 6 correspond to the radial dimensions of the outer circumference of the bobbin 2, and the bobbin 2 fits inside the outer secondary coil 6. The outer secondary coil 6 has a structure that retains its own shape, and can maintain the coil shape even without a retaining mechanism such as a bobbin. The outer secondary coil 6 is made of, for example, a rectangular wire, and is formed by bending the rectangular wire. Note that the outer secondary coil 6 and the inner secondary coil 7 may be made of a wire that can retain its own shape, such as a round wire having a diameter that can retain the coil shape, without being limited to the rectangular wire. The outer secondary coil 6 corresponds to the third coil.

[0017] The two long sides of the bobbin 2, the outer secondary coil 6, and the inner secondary coil 7 are respectively covered by two cylindrical retaining covers 8. A cylindrical iron core 20 is provided around the retaining cover 8.

[0018] 3 is a schematic cross-sectional view of the bobbin 2, the outer secondary coil 6, the inner secondary coil 7, and the retaining cover 8. In FIG. 3, the left-right direction corresponds to the axial direction. The axial dimension of the outer circumferential portion of the bobbin 2 is longer than the axial dimension of the inner circumferential portion of the bobbin 2. The axial dimensions of the outer secondary coil 6 and the inner secondary coil 7 are approximately the same. The axial dimensions of the outer secondary coil 6 and the inner secondary coil 7 are shorter than the inner circumferential portion of the bobbin 2. In the axial direction, the outer secondary coil 6 does not protrude outward beyond the outer circumferential portion of the bobbin 2, and the inner secondary coil 7 does not protrude outward beyond the inner circumferential portion of the bobbin 2.

[0019] An insulator 5 (spacer) is provided between the outer peripheral portion of the bobbin 2 and the outer secondary coil 6. The insulator 5 is sheet-like and annular, and covers the primary coils 3, 4 and the wall 2a. An insulator 10 (spacer) is provided between the insulator 5 and the outer secondary coil 6. The insulator 10 is sheet-like and annular, and has portions that protrude radially outward from both edges. The insulator 10 covers the inner peripheral portion and end faces of the outer secondary coil 6.

[0020] An insulator 11 (spacer) is provided between the inner periphery of the bobbin 2 and the inner secondary coil 7. The insulator 11 is sheet-like and annular, and covers the outer periphery of the inner secondary coil 7. In this embodiment, the inner secondary coil 7 does not protrude axially outward beyond the inner periphery of the bobbin 2, so the insulator 11 does not need to be provided. However, if the inner secondary coil 7 protrudes axially outward beyond the inner periphery of the bobbin 2, the insulator 11 is necessary as a means for holding the inner secondary coil 7.

[0021] The retaining cover 8 has two semi-cylinder portions 8a, 8b. The semi-cylinder portions 8a, 8b have a shape like a cylinder cut in half along the axial direction. Two ribs 9 are formed on the inner peripheral surface of the semi-cylinder portion 8a. The two ribs 9 are disposed between the top and end of the semicircle of the semi-cylinder portion 8a and face each other. When the semi-cylinder portion 8a is viewed in the axial direction, the ribs 9 form a substantially right-angled L-shape, and both ends of the L-shape of the ribs 9 are connected to the inner peripheral surface of the semi-cylinder portion 8a. The ribs 9 extend along the axial direction. Similar to the semi-cylinder portion 8a, ribs 9 are also formed on the inner peripheral surface of the semi-cylinder portion 8b. do.

[0022] A cylindrical retaining cover 8 is formed by butting the axially extending edges of the two semi-cylindrical portions 8a, 8b together. The outer secondary coil 6 is sandwiched between the ribs 9 of the two semi-cylindrical portions 8a, 8b. The protruding portion of the insulator 10 is interposed between the ribs 9 and the outer secondary coil 6. The inner secondary coil 7 is sandwiched between the ribs 9 of the two semi-cylindrical portions 8a, 8b. The outer secondary coil 6 and the inner secondary coil 7 are stably supported by the ribs 9.

[0023] 4 is a schematic cross-sectional view of the bobbin 2, the outer secondary coil 6, the inner secondary coil 7, and the retaining cover 8, the configuration of which has been partially modified. The shape of the rib 9 is not limited to an L-shape as long as it can stably support the outer secondary coil 6 and the inner secondary coil 7. For example, as shown in FIG. 4, when the semi-cylindrical portions 8a, 8b are viewed in the axial direction, the rib 9 may be an I-shape with the corners of an L-shape cut off.

[0024] As shown in FIG. 4, the insulator 10 extends in the axial direction, and an axial end of the insulator 10 is disposed between the rib 9 and the insulator 5. The outer secondary coil 6 extends in the axial direction. The outer secondary coil 6 is disposed between two I-shaped ribs 9 spaced apart in the axial direction. The insulator 11 extends in the axial direction, and an axial end of the insulator 11 is disposed on a surface of the rib 9 facing the bobbin 2. The inner secondary coil 7 extends in the axial direction, and protrudes outward beyond the inner circumference of the bobbin 2. An axial end of the inner secondary coil 7 is disposed between two I-shaped ribs 9 spaced apart in the axial direction.

[0025] In the transformer 1 according to the embodiment, a single bobbin 2 is used and the coils are arranged in triplicate, thereby reducing the number of bobbins 2. This makes it possible to reduce impedance and costs.

[0026] Furthermore, the outer secondary coil 6 and the inner secondary coil 7 maintain their shape even without a bobbin to hold them. Therefore, even if the number of bobbins is reduced, a triple coil structure can be realized. For example, by using rectangular wire for the windings of the outer secondary coil 6 and the inner secondary coil 7, the outer secondary coil 6 and the inner secondary coil 7 can maintain their shape without a bobbin.

[0027] The primary coils 3, 4, the outer secondary coil 6 and the inner secondary coil 7 are integrally held by the retaining cover, enabling the multiple coils to be unitized.

[0028] The insulator 5 and the insulators 10 and 11 ensure a predetermined distance between the primary coils 3, 4 and the outer secondary coil 6, or between the primary coils 3, 4 and the inner secondary coil 7, and insulate them from each other. Note that the resin bobbin 2 that holds the primary coils 3, 4 is interposed between the primary coils 3, 4 and the inner secondary coil 7, and can maintain insulation, so the insulator 11 is not necessary. However, as described above, when the inner secondary coil 7 protrudes axially outward beyond the inner circumference of the bobbin 2, the insulator 11 is necessary as a means for holding the coil. In this case, instead of the insulator 11, a member that does not have insulating properties may be used as a means for holding the coil.

[0029] The embodiments disclosed herein are illustrative in all respects and should not be considered as limiting. The technical features described in each embodiment can be combined with each other, and the scope of the present invention is intended to include all modifications within the scope of the claims and the scope equivalent to the claims. [Explanation of symbols]

[0030] 2 bobbin 3, 4 primary coil (first coil) 5 insulator (spacer) 6 outer secondary coil (third coil) 7 inner secondary coil (second coil) 8 Retaining cover 8a, 8b Semi-cylindrical part 10, 11 Insulator (spacer)

Claims

1. A first coil; a second coil arranged coaxially inside the first coil without being held by a bobbin; a third coil arranged coaxially outside the first coil without being held by a bobbin; a first coil holding bobbin disposed between the first coil and the second coil and between the first coil and the third coil, and holding the first coil; Equipped with the first coil retaining bobbin does not retain the second coil and the third coil, the second coil and the third coil have a structure for retaining their shapes; The structure is composed of a group of wires that are integrated by binding a rectangular wire or a plurality of round wires with a band or by solidifying them with resin, a retaining cover that covers and retains the inside and outside of the first coil, the second coil, and the third coil; The retaining cover is provided with a plurality of ribs spaced apart in an axial direction of the first coil, the second coil, and the third coil, The second coil and the third coil are disposed between the plurality of ribs. Transformer.

2. A spacer disposed between the first coil and the second coil or the third coil.

2. The transformer of claim 1 comprising:

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