JPH06808Y2 - Trans bobbin - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer bobbin used for a switching power supply transformer or the like.

[0002]

2. Description of the Related Art Conventionally, in order to insulate a primary coil and a secondary coil of a transformer, as shown in Japanese Utility Model Laid-Open No. 63-170915, a bobbin for winding the primary coil and a secondary coil are wound. Or a bobbin for making a double, or as shown in Japanese Patent Publication No. 3-43704, the primary coil is divided into an inner bobbin and an outer bobbin and wound, and the secondary coil is an intermediate bobbin. It has a structure in which it is wound into three layers.

[0003]

[Problems to be Solved by the Invention] However, the above-mentioned 2
In the case of a bobbin having a heavy structure, in order to secure the creepage distance between the primary coil and the secondary coil, the flanges of the bobbins must be raised so that they overlap each other, which makes molding the bobbin difficult. It was Further, in the triple structure, it is necessary to pull out the coil of the inner bobbin and connect the coil of the inner bobbin to the bobbin of the outer coil after fitting each bobbin, so that the assembling work is difficult. Furthermore, in the state where each bobbin having such a multiple structure is fitted, since each bobbin is easily disengaged or displaced, it is necessary to hold these bobbins when inserting the iron core. Was bad.

Furthermore, the conventional transformer bobbin does not take measures to dissipate the heat generated during use, and in particular, the heat generated from the inner bobbin housed in the outer bobbin or the intermediate bobbin does not easily escape to the outside. However, there is a problem that the heat tends to be muffled and the transformer becomes hot.
An object of the present invention is to solve such a problem, and it is possible to secure a sufficient creeping distance between the inner coil and the outer coil, and a creeping distance between these coils and the iron core, and to improve the assembling workability. It is an object of the present invention to provide a trans bobbin which is excellent in heat dissipation and has a high heat dissipation effect.

[0005]

In order to achieve the above-mentioned object, the present invention has a through-hole into which one end of each of a pair of U-shaped iron cores is inserted from both sides, and an inner coil is wound. The inner coil has an insulating barrier portion at both ends of the turning portion, the inner bobbin extending the terminal block in which the coil terminal is planted in one insulating barrier portion, and the outer coil has a through hole through which the inner bobbin is inserted. An outer bobbin having insulating barrier portions on both sides of the wound portion to be wound, and further extending a terminal block in which a coil terminal is planted in one insulating barrier portion, and an upper surface and both side surfaces of the outer bobbin. It has a gate shape and a coil cover on the outer side of which the other end of the iron core is located.

As an embodiment of the present invention, a stepped portion may be provided at one end of the insulating barrier portion of each of the inner bobbin and the outer bobbin. It is also possible to provide a winding drawing guide pin on the terminal block of the inner bobbin and provide an engaging portion with which the winding drawing guide pin engages at one end of the outer bobbin. Further, an engagement groove into which the step portion of the outer bobbin fits may be formed in the coil cover. Furthermore, a guide groove for winding lead-out is provided in the insulating barrier portion of the inner bobbin, and a ventilation groove is formed in the terminal block in a continuous manner with the guide groove for winding lead-out. A groove may be formed.

[0007]

In the trans bobbin constructed as described above, the creeping distance between the inner coil and the outer coil is secured by the insulating barrier portions of the inner bobbin and the outer bobbin. Further, the insulating barrier portion of the inner bobbin secures the creepage distance between the inner coil wound around the inner bobbin and the iron core. Furthermore, since the coil cover is interposed between the outer bobbin and the iron core, the insulation between the outer coil and the iron core is ensured by the creepage distance of the insulation barrier portion of the outer bobbin.

By providing the stepped portion on the insulating barrier portion of each bobbin, the creepage distance is further increased, the shoulder drop of the coil or the insulating tape is prevented, and the winding work is facilitated. In addition, if the inner bobbin is provided with a guide pin for drawing out the winding and the engaging portion that engages with this guide pin is provided on the outer bobbin, when the inner bobbin is inserted into the through hole of the outer bobbin, the guide pin and the engaging portion Since they are engaged and integrated with each other, displacement and disengagement from each other are prevented. Further, when the coil cover is provided with the engaging groove that engages with the stepped portion of the outer bobbin, the positional deviation and the falling of the coil cover are prevented. Furthermore, when the ventilation groove is provided in the insulating barrier portion and the terminal block of the inner bobbin, the heat generated from the coil wound around the inner bobbin is radiated to the outside through the ventilation groove.

[0009]

【Example】

Next, an embodiment of the present invention will be described with reference to the drawings. 1 and 2 show a transformer for a switching power supply having a transformer bobbin according to the present invention. This transformer comprises an inner bobbin 1, an outer bobbin 2, a coil cover 3, a pair of iron cores 4, and an iron core pressing fitting 5. The inner bobbin 1 has a tubular shape with a rectangular cross section having through holes 6 into which one end of each iron core 4 is inserted from both sides. This inner bobbin 1
A winding part 8 around which the primary coil 7 is wound is formed in the center of the outer surface of the coil, and both ends of the winding part 8 have an entire circumference raised by one step to form an insulating barrier part 9. A step portion 10 is formed on the entire outer periphery of each insulating barrier portion 9.

A terminal block 11 extends axially from the lower half of the one insulating barrier portion 9, and the terminal block 11 is slightly overhanging in a direction perpendicular to the axis. The coil terminal 12 is fixed to the bottom surface of the terminal block 11 by insert molding or press fitting. A support base 13 is provided so as to extend in the axial direction from the lower half of the other insulating barrier portion 9. As shown in FIG. 3, the bottom surface of the insulation barrier portion 9 on the side of the terminal block 11 is notched in a triangular shape so that the winding guide groove 1 is formed.
4 is formed in two places. On the bottom of the terminal block 11,
A guide pin 15 for drawing out the winding is provided in the vicinity of the guide groove 14 in a protruding manner. Furthermore, on the bottom of this terminal block 11, 2
Ventilation grooves 16 at some locations are formed in the axial direction, and these ventilation grooves 16 are continuous with the guide grooves 14. A ventilation groove 17 is formed in the axial direction in the bottom surface of the insulating barrier portion 9 on the support base 13 side and in the center of the bottom surface of the support base 13.

As shown in FIG. 2, the outer bobbin 2 is a tubular member having a rectangular cross section in which a through hole 18 for inserting the inner bobbin 1 is formed. A winding portion 20 around which the secondary coil 19 is wound is formed at the center of the outer surface of the outer bobbin 2.
At both ends of the winding portion 20, both side surfaces and the lower surface are raised to form an insulating barrier portion 21. The lower portion of the insulating barrier portion 21 has a higher step with the winding portion 20 than the both side portions. A step portion 22 is formed at the inner end of the upper surface of each insulation barrier portion 21. A terminal block 23 is formed by cutting out a part of the lower surface of one of the insulating barrier sections 21, and the terminal block 23 is slightly overhanging in the axial direction. As shown in FIG. 3, four coil terminals 24 are fixed to the bottom surface of the terminal block 23 by insert molding or press fitting. Winding lead-out guide grooves 25 are formed at four places from the bottom surface of the terminal block 23 to the winding portion 20. The inner bobbin 1 is provided on the end surface of the insulation barrier portion 21 opposite to the insulation barrier portion 21 provided with the terminal block 23.
An engaging portion 26 is formed with which the winding drawing guide pin 15 of FIG.

As shown in FIG. 2, the coil cover 3 is in the form of a gate having a base portion 27 for covering the upper surface of the outer bobbin 2 and both leg portions 28 for covering both side surfaces thereof. As shown in FIG. 3, an engagement groove 29 into which the step portion 22 of the outer bobbin 2 is fitted is formed. Further, on the upper surface of the base portion 27, as shown in FIG. 2, an iron core guide groove 30 into which the iron core 4 is fitted is formed. The iron cores 4 are U-shaped, and one ends of the iron cores 4 are inserted into the through holes 6 of the inner bobbin 1 to form a closed magnetic circuit having a U-shape, as shown in FIG. The iron core pressing member 5 is formed by bending a spring steel plate into a gate shape, and holds the pair of iron cores 4 as shown in FIG.

The transformer having the above structure is assembled in the following procedure. First, the primary coil 7 and the secondary coil 19 are respectively wound around the inner bobbin 1 and the outer bobbin 2 around the winding portions 8 and 20. Since each winding portion 8 and 20 has the insulating barrier portions 9 and 21 on both sides of which are raised by one step,
It is possible to prevent the coils 7 and 19 from falling or rising. The lead wires 7a at both ends of the primary coil 7 of the inner bobbin 1 are led out along the winding lead-out guide groove 14 as shown in FIG. Can be wrapped around 12. For this reason,
There is no inconvenience that the lead wire 7a is disengaged from the winding lead-out guide groove 14 and passes through the side surface of the insulating barrier portion 9 and the insulation distance described later cannot be secured. Meanwhile, the outer bobbin 2
The intermediate portion and both end portions of the secondary coil 19 can be wound around the respective coil terminals 24 through the winding drawing guide grooves 25.

Next, the insulation barrier portions 9 of the bobbins 1 and 2,
Although an insulating tape (not shown) is wound around 21, the insulating tape does not fall over the shoulder due to the step portions 10 and 22 formed at the ends of the insulating barrier portions 9 and 21, so that it is very easy to wind. Subsequently, an insulating tape (not shown) is further wound between the step portion 10 of the one insulating barrier portion 9 of the inner bobbin 1 and the step portion 10 of the other insulating barrier portion 9. This insulating tape also has shoulders 10 on both sides to prevent shoulder drop and displacement.

Then, the inner bobbin 1 is inserted from the support base 13 side to the side of the through hole 18 of the outer bobbin 2 where the engaging portion 26 is located. When the inner bobbin 1 is completely inserted, the winding bobbin guide pin 15 (see FIG. 3) of the inner bobbin 1 engages with the engaging portion 26 of the outer bobbin 2, and the inner bobbin 1 is integrated with the outer bobbin 2. Therefore, it is not displaced or dislocated in the axial direction. Next, the coil cover 3 is covered from above the outer bobbin 2, and the upper surface and both side surfaces of the outer bobbin 2 are covered with the base portion 27 and both leg portions 28 of the coil cover 3, respectively. At this time, since the stepped portion 22 of the outer bobbin 2 is engaged with the engagement groove 29 (see FIG. 3) of the coil cover 3, the coil cover 3 is prevented from being displaced in the axial direction or dropped. It

After that, one end of each iron core 4 is inserted from both sides of the through hole 6 of the inner bobbin 1 and the other end is fitted into the iron core guide groove 30 of the coil cover 3, as shown in FIG. After assembling the two iron cores 4 in a square shape, the iron core holding metal fittings 5 hold the both iron cores 4. As a result, the iron core 4 constitutes a closed magnetic circuit, and the assembly of the transformer is completed. As described above, the inner and outer bobbins 1 and 2 are provided with the guide pin 15 for drawing the winding wire.
And the outer bobbin 2 and the coil cover 3 are integrated by the engagement of the stepped portion 22 and the engagement groove 29 so that the outer bobbin 2 and the coil cover 3 are displaced from each other or come off from each other. Therefore, the work of assembling the iron core 4 can be performed quickly and easily.

In the transformer assembled as described above, the insulation between the primary coil 7 and the secondary coil 19 is achieved by insulating barrier portions 9 of the inner bobbin 1 and the outer bobbin 2, respectively, as shown in FIG. 21 lengths d ₁ , d ₂ , d ₁₁ , d ₂₂
Is secured by the creepage distance corresponding to the lengths d ₁ + d ₂ and d ₁₁ + d ₂₂ . It should be noted that the heights of the steps 10 and 22 are naturally added to this creepage distance. Also,
Insulation between the lead-out portion 7a of the primary coil 7 and the secondary coil 19 is performed by a creepage distance corresponding to a length d ₂ + t obtained by adding the length d ₂ of the insulation barrier portion 21 of the outer bobbin ₂ and the thickness t thereof. Secured by. On the other hand, the insulation between the primary coil 7 and the iron core 4 is ensured by the creepage distance of the length d ₁ and d ₁₁ of the insulation barrier portion 9 of the inner bobbin 1. Further, as shown in FIG. 1, the coil cover 3 is interposed between the secondary coil 19 and the iron core 4, so that the insulation barrier portion 21 of the outer bobbin 2 has a length d ₂ . Secured by a creepage distance corresponding to d ₂₂ .

Further, in this transformer, the arrow A,
As indicated by A ′, an air flow path is formed between the inner bobbin 1 and the outer bobbin 2 from one end to the other end by the ventilation grooves 16 and 17 and the winding drawing guide groove 14. Therefore, the heat generated from the primary coil 7 is radiated through the air flow paths A and A ′, and as a result, the temperature rise of the transformer is suppressed. In the above embodiment, the primary coil was wound around the inner bobbin 1 and the secondary coil was wound around the outer coil 2. Conversely, the secondary coil was wound around the inner bobbin 1 and the outer bobbin 2 was wound around.
The primary coil may be wound around each.

[0019]

As is apparent from the above description, according to the first aspect of the invention, the creeping distance between the inner and outer coils and the coil and the iron core are provided by the insulating barrier portions of the inner bobbin and the outer bobbin. A sufficient creepage distance is secured. Moreover, since each bobbin does not have a high flange portion as in the conventional case, the shape is simple and the molding is easy. In addition, according to the invention of claim 2, the step of the insulating barrier portion allows
The creeping distance is further increased, and there is no shoulder drop of the coil or the insulating tape, and the winding work thereof is easy. Further, according to the third aspect of the invention, since the guide pin of the inner bobbin and the engaging portion of the outer bobbin are engaged and integrated, there is no positional deviation or disengagement between the bobbins and the assembling work is easy. Further, according to the invention of claim 4, the engaging groove of the coil cover engages with the step portion of the outer bobbin to prevent the coil cover from being displaced or dropped, so that the assembling workability is good. Further, according to the invention of claim 5, the heat generated from the coil of the inner bobbin is radiated to the outside through the ventilation groove of the inner bobbin, so that the temperature rise of the transformer can be suppressed.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a transformer having a trans bobbin according to the present invention.

FIG. 2 is an exploded perspective view of the transformer shown in FIG.

FIG. 3 is an exploded perspective view of the inner and outer bobbins and the coil cover as viewed from the back side.

[Explanation of symbols]

1 ... Inner bobbin, 2 ... Outer bobbin, 3 ... Coil cover, 4 ... Iron core, 6, 18 ... Through hole,
7, 19 ... Primary and secondary coils, 8, 20 ... Winding part, 9, 21 ... Insulation barrier part, 10, 22
... Steps, 11, 23 ... Terminal blocks, 12, 24
… Coil terminals, 14… Winding guide grooves, 15
... Winding guide pins, 16, 17 ... Ventilation groove, 26
... engagement portion, 29 ... engagement groove.

Claims (5)

[Scope of utility model registration request] 1. A pair of U-shaped iron cores each have a through hole into which one end is inserted from both sides, and insulating barrier portions are provided at both ends of a winding portion around which an inner coil is wound. An inner bobbin extending a terminal block having coil terminals planted in the barrier section, and a through hole through which the inner bobbin is inserted,
An outer bobbin having an insulating barrier portion on both sides of a winding portion around which the outer coil is wound, and further extending a terminal block in which a coil terminal is planted in one insulating barrier portion, and an upper surface and both sides of the outer bobbin. A trans bobbin having a gate shape covering a surface, and a coil cover on the outer side of which the other end of the iron core is located. 2. The trans bobbin according to claim 1, wherein a step portion is provided at one end of each of the insulating barrier portions of the inner bobbin and the outer bobbin. 3. The terminal block of the inner bobbin is provided with a winding lead-out guide pin, and the one end of the outer bobbin is provided with an engaging portion with which the winding lead-out guide pin is engaged. The transbobbin according to claim 1. 4. The trans bobbin according to claim 2, wherein the coil cover is formed with an engagement groove into which a step portion of the outer bobbin is fitted. 5. A winding guide groove is provided in the insulating barrier portion of the inner bobbin, and a ventilation groove is formed in the terminal block continuously to the winding guide groove, and the other insulating barrier portion is formed. The transbobbin according to any one of claims 1 to 4, further comprising a ventilation groove.