JP2523560B2 - Trance - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer which is used in a relatively high frequency band such as a switching power supply and is required to have stable coupling and good coupling. .

2. Description of the Related Art In recent years, the development of various electronic devices has been remarkable.
In particular, in switching power supplies and the like to which transformers are applied, in order to reduce the size and weight of electronic devices, there is a demand for transformers with higher operating frequencies, higher performance, higher safety, and higher reliability.

A conventional transformer is shown in FIGS. 10 to 14. FIG. 13 is a perspective view of a conventional transformer. This transformer has a rectangular bobbin 9 with a primary winding 13 and a secondary winding 14
10 is fitted and the core 1 is incorporated. A sectional view of this transformer is shown in FIG. That is, the first bobbin 9
The primary winding 13 is attached to the second bobbin 10 and the secondary winding
14 was applied and the core 1 was incorporated and configured. In addition,
In FIGS. 13 and 14, reference numeral 2 denotes a core guide piece provided on the upper end collar 3 of the second bobbin 10, and on the upper end collar 3, a ridge 7 for determining the direction is also provided. Further, 16 is a lower end flange of the second bobbin 10 in which the lead drawing groove 5 is formed. Reference numeral 8 denotes an upper end flange of the first bobbin 9 which is sized to fit in the second bobbin 10. The lower end flange 4 of the first bobbin 9 is provided with a terminal 6 and a lead drawing groove 11 is formed. Has been done. With such a configuration, the primary winding 13 and the second bobbin 10
There was a clearance of 15 between.

The bobbins 9 and 10 used in such a transformer have a structure as shown in FIG. 11, and the second bobbin 10 has a rectangular tubular shape as shown in FIG. ₁ , R ₂ ,
The shapes of R ₃ and R ₄ were arcuate shapes, and the respective radii of curvature were R ₁ = R ₂ = R ₃ = R ₄ .

Problems to be Solved by the Invention A transformer for a switching power supply is generally composed of a plurality of primary windings and secondary windings. The number of turns is very small, from a few times to a few tens, and a single loop is often wound more.

In the conventional transformer, as shown in FIG. 10, the primary winding 13 is applied to the first bobbin 9 having a rectangular tube shape, and the second bobbin 10 having a rectangular tube shape is provided.
Is fitted on the first bobbin 9 and the secondary winding 14 is placed on the first bobbin 9.
Was applied. At this time, in particular, when there are a plurality of primary windings 13, the lead wire lead-out portion side 17 has a winding height higher than that of the other portions by the amount of the lead wire, and the lead wire is Focus on the center. Therefore, a clearance 15 is generated between the outer circumference of the primary winding 13 and the inner circumference of the second bobbin 10, but in particular, useless clearances 18 are generated at both corners on the lead wire lead-out surface, and the primary winding 13 and the secondary winding Not only is the degree of coupling between the windings 14 alienated, but the transformer has a lot of switching noise. Since the clearance 18 becomes larger as the number of windings increases, the degree of coupling is extremely deteriorated particularly in a multi-output transformer, which results in a transformer having much switching noise.

Means for Solving the Problems In order to solve the above problems, the present invention relates to an outer rectangular tubular bobbin having a through hole, and a first winding wire provided on the outer periphery of the outer rectangular tubular bobbin. An inner square tubular bobbin fitted in a through hole of the outer square tubular bobbin, and a second winding provided on the outer periphery of the inner square tubular bobbin, wherein the inner square tubular bobbin and the outer square are provided. The shape of each corner portion of the tubular bobbin is an arc shape, and the second winding is provided on the outer peripheral portion of the inner rectangular tubular bobbin between the first and second adjacent corner portions of the inner rectangular tubular bobbin. A lead line of the wire is arranged, and the radii of curvature of the first and second corner portions corresponding to the first and second corner portions of the inner rectangular tubular bobbin among the corner portions of the outer rectangular tubular bobbin. Is larger than the radius of curvature of the other corners of the outer rectangular tubular bobbin. It is configured.

Operation With the above configuration, the distance between the windings of the transformer can be made extremely small and uniform, and a transformer with excellent coupling degree and low switching noise can be obtained.

Embodiment An embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a transformer when the bobbin of the present invention is adopted. It has a structure in which a core 21 is incorporated in a wound bobbin, and a sectional view of this bobbin portion is shown in FIG.

The first rectangular bobbin 22 has an upper flange 23 and a lower flange 24, and a primary winding 25 is provided on an outer peripheral portion between them. The lower end collar 24 is provided with a terminal 26 and a lead drawing groove 27. Next, a secondary winding 31 is provided on the outer peripheral portion between the upper end flange 29 and the lower end flange 30 of the second bobbin 28 in the shape of a rectangular tube which is put on the first bobbin 22. This second bobbin
A core guide piece 38 that guides the core 21 is provided on the upper surface of the upper flange 29 of 28, and a ridge that indicates the direction of the transformer
39 are provided. A primary winding 35 is provided on the outer peripheral portion between the upper end flange 33 and the lower end flange 34 of the third cylindrical bobbin 32 which is put on the second bobbin 28. The lower end flange 30 of the second bobbin 28 and the lower end flange 34 of the third bobbin 32 have lead lead grooves 36, 3 respectively.
7 is formed, and the upper end flange 33 of the third bobbin 32 is provided with a ridge 39 showing directionality. This is a switching transformer used for VTRs, etc., and is composed of a triple-fitting bobbin.

Here, a sectional view of the body winding portion of each bobbin is shown in FIG. Each tubular first bobbin 22 has four corners R ₁₁ , R
The shapes of ₂₁ , R ₃₁ , and R ₄₁ are arcuate shapes, and the respective radii of curvature are R ₁₁ = R ₂₁ = R ₃₁ = R _41.
The corners of 28 are also arcuate, and the radius of curvature of each is slightly larger than the radius of curvature of the corner of the first bobbin 22 as shown in FIG. 4, but R ₁₂ = R ₂₂ = R
₃₂ = R ₄₂ . This is as shown in FIG.
There is one type of primary winding 25 for the first bobbin 22, and the primary winding 25 can be used without changing the radius of curvature of the four corners.
This is because the clearance 40 between the outer circumference and the inner circumference of the second bobbin 28 is small. The third bobbin 32 also has four corners R ₁₃ , R
The shapes of ₂₃ , R ₃₃ , and R ₄₃ are arcuate, but the radius of curvature of each is R ₃₃ = R ₄₃ , R ₁₃ = R _{23 as} shown in FIG.
And R ₃₃ = R ₄₃ > R ₁₃ = R ₂₃ .
This is because a plurality of windings are formed on the second bobbin 28, so the outer circumference of the lead wire lead-out portion located on the outer circumference of the second bobbin 28 between the corner portions R ₃₂ and R ₄₂ is large as shown in FIG. This is because That is, the second bobbin of the third bobbin 32
The corners R ₃₃ and R ₄₃ corresponding to the corners R ₃₂ and R ₄₂ of 28 have a larger radius of curvature than the other corners R ₁₃ and R ₂₃ . When such a bobbin is used, the clearance 41 between the secondary winding 31 wound on the second bobbin 28 and the inner circumference of the third bobbin 32 becomes uniform as shown in FIG. , The primary winding 25 of the first bobbin 22, the secondary winding 31 of the second bobbin 28, and the primary winding 35 of the third bobbin 32 can be closest to each other.

FIG. 7 shows a sectional view of the double-fitted bobbin. The second bobbin 28 at this time is shown in FIG. 8, and the radius of curvature of this corner portion is R ₁ = R ₂ <R ₃ = R ₄ . This is to increase the size of the radius of curvature of the corners on both ends of the leader line. Figure 9 shows a corner R ₄
This is a structure in which only the size of the curve radius of is larger than the radius of curvature of the other corners. As shown in FIG. 8, the radius of curvature of each corner may be changed to R ₄ > R ₃ > R ₂ and R ₁ .

Although not shown, the radius of curvature of the corner portion of the first bobbin 22 may be changed to make the radius of curvature of the corner portion of the second bobbin 28 the same.

Further, both the size of the radius of curvature of the corner portion of the first bobbin 22 and the size of the radius of curvature of the corner portion of the second bobbin 28 may be changed. By changing the size of the radius of curvature of the corner portion of each bobbin in this way, it is possible to further increase the degree of coupling.

Further, even in a transformer composed of a plurality of bobbins, among the corner portions of the outer rectangular tubular bobbin, the corners of the outer rectangular tubular bobbin corresponding to the lead wire side corners of the inner rectangular tubular bobbin. It is possible to provide a transformer with a high degree of coupling by making the radius of curvature of the portion larger than the radius of curvature of the other corner portions.

EFFECTS OF THE INVENTION As described above, according to the present invention, it is possible to minimize the clearance between the coil wound on each bobbin and the bobbin, improve the degree of coupling between the coils, and perform switching. It is possible to realize a high output transformer with less noise. Further, the degree of coupling is improved, the stability of the circuit of the switching power supply can be increased, and the circuit design can be facilitated.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the transformer of the present invention, and FIG. 2 is a sectional view thereof. FIG. 3 shows 3 adopted in the present invention.
FIG. 4 is a sectional view of a combination of the heavy fitting bobbins, FIG. 4 is a sectional view of a second bobbin, and FIG. 5 is a sectional view of a third bobbin. FIG. 6 is a cross-sectional view when wound around a triple fitting bobbin, and FIG.
Sectional views at the time of the heavy fitting bobbin, FIGS. 8 and 9 are sectional views of the second bobbin. FIG. 10 is a sectional view of a conventional transformer wound around a double-fitting bobbin, FIG. 11 is a sectional view of a conventional bobbin combined, FIG. 12 is a sectional view of the second bobbin, and FIG. Is a perspective view of a conventional transformer and FIG. 14 is a sectional view thereof. 21 …… Core, 22 …… First bobbin, 25 …… Primary winding, 26…
… Terminal, 28 …… Second bobbin, 31 …… Secondary winding, 32 …… Third bobbin, 35 …… Primary winding.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Matsuda 1006 Kadoma, Kadoma City, Matsushita Electric Industrial Co., Ltd. (56) Bibliographic references Sho 56-2230 (JP, U)

Claims (1)

(57) [Claims] 1. An outer rectangular tubular bobbin having a through hole, a first winding provided on the outer periphery of the outer rectangular tubular bobbin, and an inner corner fitted into the through hole of the outer rectangular tubular bobbin. A tubular bobbin and a second winding provided on the outer periphery of the inner rectangular tubular bobbin are provided, and the corners of the inner rectangular tubular bobbin and the outer rectangular tubular bobbin are arcuate in shape. ,
The lead wire of the second winding is disposed on the outer peripheral portion of the inner rectangular tubular bobbin between the adjacent first and second corner portions of the inner rectangular tubular bobbin, and the lead wire of the second rectangular tubular bobbin is provided. Of the corner portions, the size of the radius of curvature of the first and second corner portions corresponding to the first and second corner portions of the inner rectangular tubular bobbin is defined as the other corner portion of the outer rectangular tubular bobbin. A transformer that is larger than the radius of curvature of.