JP2002141229A - Transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To further prolong the creeping distance of a transformer such that, particularly, the creep distance required for meeting a safety standard, etc., is secured, without making large design changes. SOLUTION: This transformer is provided with a bobbin 2 which has a through-hole 5, made through its central part and is wound with a primary coil 6 and a secondary coil 7, an insulating case 3 having openings 15 at the positions corresponding to both ends of the through hole 5, and a pair of core members 4a and 4b at least partially inserted into the through-hole 5 of the bobbin 5, through the openings 15 of the case 3 and butted against each other in the hole 5 and on the outside of the case 3. In addition, an insulating member 18 is provided between at least one 4a of the core members 4a and 4b and the through-hole 5 of the bobbin 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer used, for example, for a power supply of industrial equipment.

[0002]

2. Description of the Related Art In general, a transformer used for a power supply section of industrial equipment or the like must satisfy safety standards in various countries to which the transformer is destined and various safety standards depending on applications. Further, in the power supply section, there are restrictions on circuit design due to the application, design, performance, and the like on the side to which power is supplied, and it is necessary to design the structure and specifications of the transformer within the restrictions. Furthermore, transformers are an important part in circuit design, and primary-secondary conversion efficiency is improved, and sufficient measures to prevent smoke, fire, fire, and electric shock in the event of abnormalities, that is, so-called HHKK, are not taken. must not. For this reason, the transformer must perform tests to confirm the respective regulatory items of the safety standard and satisfy all of them.

FIG. 8 shows an example of the configuration of a conventional transformer.
And FIG. FIG. 8 is an exploded perspective view showing the configuration of the transformer 100, and FIG.
It is a perspective view which shows the assembly structure of 00.

The transformer 100 includes a bobbin 101,
An insulating case 102 and a pair of cores 103a and 103b are provided.

The bobbin 101 has a pair of cores 10 at the center.
A through-hole 104 for inserting 3a, 103b is formed, and a cylindrical portion 107 around which a primary coil 105 and a secondary coil 106 are wound around an outer peripheral portion, and a primary coil 105 of the cylindrical portion 107 are formed. At both ends and both ends of the secondary coil 106,
The flanges 108a and 108b and the flanges 108c and 108d are formed so as to protrude over the entire circumference of the outer peripheral portion.
And these flanges 108a, 108b, 108c, 1
08d, a plurality of terminals electrically connected to the primary coil 105 and the secondary coil 106 to terminal portions 109a and 109b formed continuously with the flanges 108a and 108d located at both ends of the cylindrical portion 107, respectively. Pin terminal 11
0.

The insulating case 102 has a substantially box shape in which the bobbin 101 can be housed inside through the opening 111 while the plurality of pin terminals 110 are exposed to the outside through the opening 111. The insulating case 102 includes a bobbin 1
The pair of cores 103a and 103b are inserted into the through holes 104 of the cylindrical portion 107 at positions corresponding to both ends of the cylindrical portion 107 of FIG.
Is provided with an insertion window 112 for insertion into the.

Each of the pair of cores 103a and 103b has a substantially E-shape. A part is inserted into the hole 104, and the inside of the through hole 104 and the insulating case 102
A magnetic path is formed by abutting the outside.

FIG. 10 is a sectional view of a main part showing the internal structure of the transformer 100 configured as described above. In the transformer 100, the distance between along the surface connecting 'and point B' point A and has a creepage distance S ₁ 'of the primary coil 105 and the secondary coil 106. Also, this transformer 100
Then, the distance along the surface connecting the point C ′ and the point D ′ is the creepage distance S ₂ ′ between the core 103a and the primary coil 105, and connects the point E ′ and the point F ′. The distance along the surface is the creeping distance S ₃ ′ between the core 103b and the secondary coil 106.

[0009]

In the above-mentioned transformer, it is required to further extend the creepage distance.

For example, in a conventional transformer, in order to secure a creepage distance between the primary coil and the secondary coil, the bobbin around which the primary coil and the secondary coil are wound is divided, or the primary coil and the secondary coil are separated. An insulating tape is interposed between the secondary coil and the secondary coil. In a conventional transformer, a pair of cores, a primary coil and a secondary coil inserted into a bobbin are used.
In order to secure the creepage distance with the next coil, the bobbin is housed in an insulating case, and a rib or the like is provided inside the insulating case to secure the creepage distance.

However, the general safety standard I
In addition to EC950, CSA22.2, and UL, when used for special purposes such as medical equipment, it is necessary to secure a creepage distance about twice as large.

In this case, the conventional transformer 100 described above is used.
Then, the bobbin 101 and the insulating case 102 corresponding to the
A new pair of cores 103a, 103b, etc., must be designed.

For this reason, in the conventional transformer 100, the size of the bobbin 101 is increased due to a design change,
It is necessary to mold a new die such as the insulating case 102 and the like, which leads to an increase in capital investment and an increase in design man-hours. Further, in the conventional transformer 100, increasing the size of the transformer 100 has a serious adverse effect in designing a circuit that is a highly efficient, compact and lightweight power supply by increasing the frequency.

In view of the foregoing, the present invention has been proposed in view of such a conventional situation, and it is possible to further extend the creepage distance, and in particular, to increase the creepage distance required to satisfy safety standards and the like. An object of the present invention is to provide a transformer that can be secured without making a change.

[0015]

According to the present invention, there is provided a transformer having a bobbin in which a through hole is formed in a center portion and a primary coil and a secondary coil are wound in an outer peripheral portion, and a bobbin. An insulating case housed inside and having openings at positions corresponding to both ends of the through hole, and at least a part of the insulating case is inserted into the through hole of the bobbin through the opening of the insulating case and the insulating case. A pair of core members that are externally contacted. Further, an insulating member is provided between at least one of the pair of core members and the through hole of the bobbin.

In this transformer, since an insulating member is provided between at least one of the pair of core members and the through hole of the bobbin, the pair of core members, the primary coil and the secondary coil are provided. The creepage distance with the coil can be extended.

In this transformer, a surface of at least one of the pair of core members facing the through hole of the bobbin is cut, and an insulating member is provided at the cut portion. Is preferred.

As a result, the creepage distance required to satisfy safety standards and the like can be secured without making a large design change.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 5 show one structural example of a transformer to which the present invention is applied. FIG. 1 is an exploded perspective view showing the configuration of the transformer 1, FIG. 2 is a perspective view showing an assembly structure of the transformer 1, and FIG.
FIG. 4 is a bottom view showing the assembly structure of the transformer 1, and FIG. 5 is a side view showing the assembly structure of the transformer 1.

The transformer 1 includes a bobbin 2, an insulating case 3, and a pair of cores 4a and 4b.

The bobbin 2 has a pair of cores 4a, 4
a cylindrical portion 8 around which a primary coil 6 and a secondary coil 7 are wound, and both ends of the primary coil 6 of the cylindrical portion 8 In addition, flanges 9a, 9b and flanges 9c, 9d are formed at both ends of the secondary coil 7 so as to protrude over the entire outer periphery. That is, the cylindrical portion 8 has a substantially cylindrical shape in which a through hole 5 for inserting a pair of cores 4a and 4b is formed at the center portion, and is formed to protrude over the entire outer peripheral portion. The first coil 6 is located between the flange 9a and the flange 9b.
And the flange 9c and the flange 9d
And the second coil 7 is wound therebetween.

The bobbin 2 is electrically connected to the primary coil 6 and the secondary coil 7 at terminal portions 10a and 10b formed continuously with flanges 9a and 9d located at both ends of the cylindrical portion 8, respectively. Have a plurality of pin terminals 11 connected thereto. Specifically, the terminal portions 10a and 10b are
a, 9b are formed to extend in the width direction on one side,
In the terminal portions 10a and 10b, a plurality of pin terminals 11 are implanted at equal intervals toward the side opposite to the through hole 5 of the tubular portion 8. These pin terminals 11 are soldered in a state in which lead wires (not shown) of the primary coil 6 and the secondary coil 7 are wound.

The flanges 9b and 9c located between the first coil 6 and the second coil 7 have guide grooves 12 for passing the lead wires of the primary coil 6 and the secondary coil 7, respectively. Is provided.

Further, of the flanges 9b and 9c located between the first coil 6 and the second coil 7, an outer peripheral portion of the flange 9c on the second coil side has the guide groove 12 described above.
A groove 13 is provided over the entire periphery except for the portion provided with the groove 13 to be engaged with an insulating wall of the insulating case 3 described later.

The insulating case 3 has a substantially box-like shape in which the bobbin 2 can be housed through the opening 14 while the plurality of pin terminals 11 are exposed to the outside through the opening 14. The insulating case 3 is provided with insertion windows 15 for inserting the pair of cores 4 into the through holes 5 of the cylindrical portion 8 at positions corresponding to both ends of the cylindrical portion 8 of the bobbin 2. I have.

The groove 1 provided in the flange 9c on the side of the second coil 7 is provided inside the insulating case 3.
An insulating wall 16 to be engaged with 3 is formed to protrude.

In this case, in the transformer 1, when the bobbin 2 is housed in the insulating case 3, the groove 13 provided in the flange 9 c and the insulating wall 1 provided in the insulating case 3
6, the primary coils 6 and 2 wound around the outer peripheral portion of the tubular portion 8 inside the insulating case 3.
The next coil 7 can be isolated.

The pair of cores 4a and 4b are of a so-called EE type and are made of a magnetic material such as ferrite. Specifically, each of the pair of cores 4a and 4b is formed of a substantially rectangular parallelepiped base 17a and a first leg 17b extending from both ends of the base 17a in a direction orthogonal to the base 17a.
And the second leg 17c and the first leg 17 of the base 17a.
It has a third leg 17d formed to extend in a direction perpendicular to the space between b and the second leg 17c, and has a substantially E-shape as a whole.

The pair of cores 4a and 4b are arranged such that the third legs 17d of the pair of cores 4a and 4b move from the insertion window 14 of the insulating case 3 to the cylindrical portion 8 with respect to the bobbin 2 housed inside the insulating case 3. The third legs 17d are inserted into the through-hole 5 and are brought into contact with each other inside the through-hole 5, and the first legs 17d are connected to each other.
The second leg portions 17b and 17c abut on the outside of the insulating case 3. Thus, a magnetic path is formed in the transformer 1.

In this transformer 1, a pair of cores 4
The insulating case 3 insulates the first and second legs 17a and 17cb of the a and 4b from the primary coil 6 and the secondary coil 7 wound around the cylindrical portion 8 of the bobbin 2. .

In the transformer 1 to which the present invention is applied, at least one of the pair of cores 4a and 4b (here, the core 4a on the primary coil 6 side) and the bobbin 2
Insulating cover 18 made of an insulating member
Is provided.

Specifically, in the transformer 1, the thickness of the core 4a on the primary coil 6 side (hereinafter, referred to as the first core 4a) is set to the core 4b on the secondary coil 7 side (hereinafter, the second core 4a). 4b)).
The core 4a is provided with an insulating cover 18 having a thickness substantially equal to that of the second core 4b.

As shown in FIGS. 1 and 6, the insulating cover 18 is made of a resin molding material, and includes a base fitting portion 18a of the first core 4a fitted to the base 17a,
A first fitting portion 17b fitted to the leg 17b of the
A second fitting portion 18c fitted with the leg 17c of the
And a third fitting portion 18d fitted with the leg portion 17d, and these fitting portions 17a, 17b, 17c, and 17d are formed as one insulating member that covers the first core 4a. . Here, for example, Rinite FR530 manufactured by DuPont is used as the resin molding material.

The insulating cover 18 is mounted on the first core 4a as shown in FIGS. 2, 3 and 5.
The first core 4a is inserted through the insertion window 14 of the insulating case 3 into the through-hole 5 of the cylindrical portion 8 while the thickness of the first core 4a is substantially equal to the thickness of the second core 4b.

FIG. 7 is a sectional view of a main part showing the internal structure of the transformer 1 configured as described above.

In the transformer 1, the distance between the points A and B along the surface connecting the points A and B is the primary coil 6 and the secondary coil 7
And has a creepage distance S ₁ between. Also, this transformer 1
Then, the distance along the surface connecting the point C and the point D is the creepage distance S ₂ between the core 4a and the primary coil 6, and
The distance along the surface connecting point E and point F is the core 4b
And the creepage distance S ₃ between the secondary coil 7.

In the transformer 1, an insulating cover 18 is provided between the first core 4a and the through hole 5. Specifically, inside the through hole 5, between the third leg 17d forming the first core 4a and the inner peripheral surface of the through hole 5, a third fitting forming the insulating cover 18 is performed. Part 18
d is interposed.

As a result, in the transformer 1, the first core
Creepage distance S between 4a and primary coil 6 _TwoFIG. 1 described above
0 and the core 103a of the conventional transformer 100 shown in FIG.
Creepage distance S with primary coil 105_Two’
Can be extended by the distance along the surface of -18
You. Therefore, in this transformer 1, a further creepage distance can be obtained.
Separation can be secured.

By the way, in addition to the above-mentioned general safety standards IEC950, CSA22.2, and UL, when used for special purposes such as medical equipment, a creepage distance of about twice is secured. There is a need to.

Specifically, in the conventional transformer 100 shown in FIG. 10 described above, in order to satisfy a general safety standard, the creepage distance S ₁ ′ between the primary coil 105 and the secondary coil 106 is set to 6. It is necessary to secure 4 mm or more, and the creepage distance S ₂ ′ between the core 103 a and the primary coil 105 and the creepage distance S ₃ ′ between the core 103 b and the secondary coil 106 need to be 3.2 mm or more.

On the other hand, when used for special purposes such as medical equipment, the primary coil 105 and the secondary coil 10
'There a need to secure more than 12 mm, the core 103a and the creepage distance S ₂ between the primary coil 105' creeping distance S ₁ between 6 and core 103b and the creeping distance S ₃ 'of 6mm or more each of the secondary coil 106 Need to secure.

In this case, the above-described conventional transformer 100
Then, for example, the flanges 108a and 108 of the bobbin 101
It is necessary to make design changes such as increasing b, 108c and 108d.

For this reason, in the conventional transformer 100, the design is changed to increase the size, or the bobbin 101
It is necessary to mold a new die such as the insulating case 102 and the like, which leads to an increase in capital investment and an increase in design man-hours. Further, in the conventional transformer 100, increasing the size of the transformer 100 has a serious adverse effect in designing a circuit that is a highly efficient, compact and lightweight power supply by increasing the frequency.

Therefore, such a conventional transformer 100
By applying the present invention, it is possible to secure the creepage distance required to satisfy safety standards and the like without making a large design change.

That is, in the transformer 1 to which the present invention is applied, when the insulating cover 18 is provided between the first core 4a and the through hole 5, the thickness of the first core 4a is reduced by 1 mm. A cutting process is performed, and an insulating cover 18 having a thickness substantially equal to that of the second core 4b is formed on the cut portion.
May be provided.

Incidentally, safety standards have relaxed provisions.
An insulating member having a thickness of 1 mm or more is formed by a pair of cores 4a and 4b.
And between the primary coil 6 and the secondary coil 7, it is possible to add to the surface along the space.

The pair of cores 4a and 4b are made of a magnetic material such as ferrite, and an oxide layer is formed on the surface due to the effect of firing during the manufacturing process. Not functioning as

Therefore, a gap necessary for providing the insulating cover 18 between the bobbin 2 and the through hole 5 is formed by cutting the oxide layer formed on the surface of the first core 4a. it can.

In the transformer 1, the first core 4 a on which the insulating cover 18 is mounted and the second core 4 b are brought together inside the through hole 5 of the bobbin 2, so that the first core 4 a An insulating cover 18 having a thickness of 1 mm or more can be provided between 4a and the through hole 5. In this case, the first core 4a and the second core 4b
Is preferably configured such that, inside the through hole 5, the primary coil or the secondary coil is located closer to the primary coil side or the secondary coil side than the intermediate position in the insertion direction.

Thus, when the transformer 1 is used for a special purpose such as a medical device, for example, the spatial distance between the first core 4a and the primary coil 6 can be reduced without major design change. 1 mm or more, and the creepage distance required to satisfy the safety standard is reduced by the first core 4a.
Can be ensured by the insulating cover 18 attached to the base. The creepage distance can be extended by a distance along the surface of the insulating cover 18 attached to the first core 4a, and the length can be set arbitrarily.

Therefore, in the transformer 1, it is possible to comply with the safety standard of any destination in the power supply design without increasing the size due to the design change.
Further, the shape of the transformer can be made common, and the design of the power supply circuit can be freely performed.

More specifically, there is no need to newly design a complicated mold for molding the bobbin 2 and the insulating case 3.
The bobbin 2 and the insulating case 3 can be used in common, so that only a mold for molding the insulating cover 18 is required. For this reason, for example, the investment amount for the mold equipment is about 1/3 or less, and the number of design steps such as bobbin design is completely unnecessary.

In this example, although a new cutting process is required for the first core 4a, a pair of cores 4a and 4b
Since there is a step of performing gap processing when manufacturing
By multiplying the number of cutting blades used in this step, processing costs can be reduced.

The above-described transformer 1 has a configuration in which an insulating cover 18 as an insulating member is provided between the first core 4a and the through hole 5 among the pair of cores 4a and 4b. The configuration is not necessarily limited to such a configuration, and any configuration may be used as long as an insulating member is provided between at least one of the pair of cores 4 a and 4 b and the through hole 5. At this time, the thickness of the core on which the insulating member is provided does not necessarily need to be smaller than the thickness of the other core, and the thickness is arbitrary.

[0056]

As described above in detail, according to the transformer of the present invention, the insulating member is provided between at least one of the pair of core members and the through hole of the bobbin. As a result, the creepage distance can be further extended, and in particular, the creepage distance required to satisfy safety standards and the like can be ensured without major design changes.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a configuration example of a transformer to which the present invention is applied.

FIG. 2 is a perspective view showing an assembly structure of the transformer.

FIG. 3 is a plan view showing an assembly structure of the transformer.

FIG. 4 is a bottom view showing an assembly structure of the transformer.

FIG. 5 is a side view showing an assembly structure of the transformer.

FIG. 6 is a perspective view showing a state where an insulating cover is attached to the first core.

FIG. 7 is a sectional view of a main part showing an internal structure of the transformer.

FIG. 8 is an exploded perspective view showing one configuration example of a conventional transformer.

FIG. 9 is a perspective view showing an assembly structure of the conventional transformer.

FIG. 10 is a sectional view of a main part showing an internal structure of the conventional transformer.

[Description of Signs] 1 transformer, 2 bobbin, 3 insulating case, 4a, 4
b A pair of cores, 5 through holes, 6 primary coils, 7 secondary coils, 8 cylindrical portions, 9a to 9d flanges, 10a,
10b terminal part, 11 pin terminal, 12 guide groove, 13
Groove, 14 opening, 15 insertion window, 16 insulating wall, 18
Insulation cover

Claims (7)

[Claims] 1. A through hole is formed in a center portion, and a through hole is formed in an outer peripheral portion.
A bobbin around which a secondary coil and a secondary coil are wound; an insulating case accommodating the bobbin therein; and an opening provided at positions corresponding to both ends of the through hole; and an opening of the insulating case. A pair of core members that are inserted at least partially into the through holes of the bobbin, and are engaged with each other inside the through holes and outside the insulating case, and at least one core of the pair of core members A transformer, wherein an insulating member is provided between the member and a through hole of the bobbin. 2. A surface of at least one of the pair of core members facing the through hole of the bobbin is cut, and an insulating member is provided at the cut portion. The transformer according to claim 1. 3. The transformer according to claim 2, wherein the insulating member is inserted into a through hole of the bobbin while being attached to a cut portion of the core member. 4. The transformer according to claim 1, wherein the insulating member is made of a resin molding material. 5. A cylindrical portion of the bobbin is provided with flange portions projecting over the entire outer peripheral portion thereof at both ends of the primary coil and both ends of the secondary coil. The transformer according to claim 1, wherein the transformer is provided. 6. The transformer according to claim 1, wherein the bobbin is provided with a plurality of connection terminals electrically connected to the primary coil and the secondary coil. 7. A tubular portion of the bobbin is provided with a flange formed so as to protrude over the entire periphery of the bobbin at least between the primary coil and the secondary coil. 2. The transformer according to claim 1, wherein the insulating case is provided with an engagement portion that is engaged with the flange portion. 3.