JPH07201604A - Transformer - Google Patents

Abstract

PURPOSE:To provide a transformer in which reduction is realized in the size and cost while achieving expected performances and allowing automation of assembling process. CONSTITUTION:An insulating film 10b is wound, by a predetermined number of turns, at least around the primary winding 10 or the secondary winding only at a part where the potential difference between both windings or between the winding and the core is relatively high or at a predetermined part requiring high insulation according to safety regulations, for example. This insulation film 10b ensures a required creeping distance between respective layers of each coil thus eliminating the need of expensive lead wire having a barrier tape layer or a three layer insulation coating.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transformer in which a primary winding and a secondary winding are wound around a bobbin in a radial direction of the bobbin so as to be miniaturized.

[0002]

2. Description of the Related Art A transformer for a high frequency power source, which is intended to be miniaturized, generally has a structure in which a primary winding and a secondary winding are superposed on a bobbin in the radial direction of the bobbin and alternately wound. There is. In this type of transformer, it is necessary to satisfy the conditions of the electrical insulation and the creepage distance between the primary winding and the secondary winding defined in the safety standard. In order to ensure such safety, the conventional transformer has a configuration as shown in FIG. 6 or 7.

That is, the transformer shown in FIG. 6 has a structure generally adopted in the past, and barrier tapes 2 are wound around both ends (upper and lower ends of the drawing) of the coil bobbin 1 to form both sides of the coil bobbin 1. The primary winding 3 is wound around the barrier tape 2 positioned between the barrier tape 2 and the insulating tape 4 around the outer circumference of each of the barrier tape 2 and the primary winding 3, and the first layer is wound. Layers have been formed. The second coil winding layer formed by the secondary winding 5 and the third coil winding layer formed by the primary winding 3 are also sequentially laminated in the same configuration as described above. The barrier tapes 2 on both sides of the coil bobbin 1 ensure a creeping distance between the primary winding 3 and the secondary winding 5 that satisfies the safety regulation, and the insulating tape 4 connects the primary winding 3 with the creeping distance. Electrical insulation is provided between each coil winding layer and the secondary winding 5.

In the figure, an E-shaped core 6 and an I-shaped core 7 are shown.
The magnetic circuit is formed by (the E-shaped core 6 may form the magnetic circuit in some cases), and the middle leg 6a of the E-shaped core 6 is inserted into the insertion hole 1a of the coil bobbin 1 at one end side. I-shaped core 7 inserted through the core bobbin 1 and fitted in the core mounting recess 1b on the other end side of the coil bobbin 1.
The end portions of the middle leg 6a and the pair of side legs 6c and 6d integrally connected to both sides of the middle leg via the connecting portions 6b are pressed against each other and fixed to each other by a holding member (not shown). ing. The coil bobbin 1 is attached to both the cores 6 and 7.

On the other hand, in the transformer of FIG. 7, except for the barrier tape 2 of FIG. 6, the primary winding 8 is formed by using a conductive wire having three layers of insulating coating. The creeping distance required for safety standards is provided between the primary winding 8 and the secondary winding 5 by the three insulating coating layers of the primary winding 8 forming the first and third coil winding layers, respectively. To ensure that you have an insulation system. In some cases, instead of the primary winding 8, the secondary winding 5 is formed by using a conductive wire having three layers of insulating coating layers. Other configurations are the same as those in FIG.

[0006]

However, the transformer shown in FIG. 6 requires a space of about 4 to 6 mm for providing the barrier tape 2 on both sides of the coil bobbin 1, so that the coil bobbin 1 has a space corresponding thereto. The shape becomes large. Further, since the step of providing the barrier tape 2 on both sides of the coil bobbin 1 is required for each coil winding layer, there are drawbacks that assembly workability is poor and manufacturing cost is high.

On the other hand, since the transformer of FIG. 7 does not include the barrier tape 2 of FIG. 6, it has the advantages that it can be made smaller and the assembly workability is improved as compared with the transformer of FIG. On the other hand, the primary winding 8 or the secondary winding 5
In addition, since an expensive conductive wire with three layers of insulating coating is used, the material cost is high, and the thickness between the coil winding layers and the wire is generated, increasing the winding thickness of the entire coil winding layer,
Furthermore, there is a problem that the magnetic coupling between the primary winding 8 and the secondary winding 5 is weakened, and the desired performance of the transformer cannot be obtained. Further, both ends (winding start end and winding end end) of the primary winding 8 or the secondary winding 5 are soldered to a pair of primary terminal pins 9a, 9b or a secondary terminal pin (not shown). In order to electrically connect the two layers, a complicated work of peeling off the three insulating coating layers in that portion is required. The existence of this work is a factor that hinders automation of the assembly process.

Therefore, it is an object of the present invention to provide a transformer having a structure capable of achieving both miniaturization and cost reduction, obtaining desired performance, and automating an assembly process. is there.

[0009]

The present invention is, as a technical means for achieving the above-mentioned object, a primary winding and a secondary winding wound on a bobbin attached to a core in a radial direction of the bobbin. In the formed transformer, the insulating film is wound a predetermined number of times only on a predetermined portion of at least one of the conductor wires of the primary winding and the secondary winding where high insulation is required.

[0010]

Operation: A primary winding and a secondary winding in a predetermined portion where high insulation is required, for example, a portion where a potential difference between both windings or between the winding and the core is relatively large, or a portion required for safety standards. Since at least one of the conductive wires of, for example, both ends of the coil winding layer of the primary winding is wound with the insulating film a predetermined number of times, the insulating film substantially allows each coil winding layer or coil winding layer to be wound. A sufficient creeping distance between the core and the core can be secured.

Therefore, the size can be remarkably reduced as compared with the conventional one in which the creepage distance is secured by the barrier tape, and the insulating film is provided on at least one of the primary winding wire and the secondary winding wire. Since it is only wound around the specified part where high insulation is required,
Compared with the one shown in FIG. 7 in which the total length of the primary winding or the secondary winding is formed by a conductor having three insulating coating layers, the width of the coil winding layer when the number of turns is set to a predetermined value (in the bobbin axis direction) The length can be reduced, and the size can be reduced accordingly. Also,
Since there is no need to use an existing expensive conductor having three layers of insulation coating, the material cost can be reduced, and a high degree of magnetic coupling between the primary winding and the secondary winding can be maintained to improve the transformer. The performance of the period is obtained.

Further, since the barrier tape is not provided, the assembling workability is remarkably improved, the manufacturing cost can be reduced, and the material cost can be reduced and the cost can be greatly reduced. Moreover, in the case of a transformer using an existing conductor having three layers of insulating coating, no manual work such as peeling of the insulating coating at both ends of the conducting wire is required, so that the assembly process can be automated.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical sectional view of a transformer according to an embodiment of the present invention. In the figure, the first layer and the third layer
The primary winding 10 forming the coil winding layer of the first layer is formed by using a normal urethane coated conductive wire 10a, and
A polyester-based insulating film 10b having an extremely thin thickness of 10 to 20 μm and having high pressure resistance is triple-layered (three layers) on the urethane-coated conductive wires 10a at the winding start and winding end portions of both coil winding layers. ) Is wrapped around. The number of windings is not limited to triple, but may be double or quadruple or more, and is appropriately set according to the required insulation property.

The portion around which the above-mentioned insulating film 10b is wound is, for example, the portion where the potential difference between the windings 10 and 5 is relatively large, as shown by the dashed line in FIG. It is a portion where the potential difference between the cores 6 and 7 is relatively large, or a portion where a predetermined high insulation property is required in safety standards. Therefore, by the insulating film 10b wound around the urethane-coated conductor wire 10a of the primary winding 10 in the portion where the potential difference is large,
A creepage distance between the coil winding layers can be secured. On the other hand, between the coil winding layers of the primary winding 10 and the secondary winding 5,
It is electrically insulated by the insulating tape 4 as in the conventional case. The insulating tape 4 prevents the windings 10 and 5 from being disturbed, and mechanically protects the insulating film 10b wound in three layers against the force applied inward in the radial direction of the bobbin 1. There is.

As compared with the transformer of FIG. 6 in which the barrier tape 2 secures the creepage distance, the above-mentioned transformer can reduce the axial dimension of the bobbin 1 as is clear from the comparison between FIG. 6 and FIG. Further, the insulating film 10b is only wound around the winding start portion and the winding end portion of each coil winding layer of the primary winding 10, and the intermediate portion of both portions and the end line portions of both ends are covered with urethane. The conductor wire 10a is exposed as it is. Therefore, as compared with the transformer of FIG. 7 in which the entire length of the primary winding 8 is formed of the existing conductor having the three insulating coating layers, the width of the coil winding layer when set to a predetermined number of turns (in the bobbin axis direction) The length) becomes smaller, and the shape of the coil bobbin 1 can be made smaller accordingly.

Further, since the existing expensive conductor wire 8 having the three insulating coating layers shown in FIG. 7 and the barrier tape 2 shown in FIG. 6 are not used, the material cost can be reduced. On the other hand, the work of providing the barrier tape 2 is unnecessary, and furthermore, the insulating film 10b of FIG. 1 is partially wrapped around only the required portion and not around the end line portion, so that soldering is required. Since the work of peeling off the insulation coating layer of is unnecessary,
Assembling workability is improved and manufacturing cost can be reduced as compared with the conventional case. Since both the manufacturing cost and the material cost described above can be reduced, a significant cost reduction can be achieved. Moreover, since the urethane-coated conductive wire 10a is closely wound as it is in most parts of each coil winding layer of the primary winding 10 as it is, the leakage inductance can be reduced and the primary winding 10 and A high degree of magnetic coupling can be maintained between the secondary windings 5 and desired performance of the transformer can be obtained.

In the transformer of this embodiment, the insulating film 10b is wound only around the required portion of the urethane coated conductive wire 10a, so that the insulating coating layer on the end line portion for soldering as shown in FIG. 7 is peeled off. Since the manual work can be excluded, the assembly process can be automated. This automation will be described below with reference to FIG.

In FIG. 3, the urethane-coated conductive wire 10a wound around the wire drum 11 is fed by a pair of feeding rollers 12 and fed by a pair of feeding rollers 13 to the coil bobbin 1 which is rotationally driven. The primary winding 10 is wound around the coil bobbin 1.
A film winding machine 14 and a conductor cutting machine 15 are installed between the wire drum 11 and the coil bobbin 1 to wind the insulating film 10b and the coil bobbin 1.
The winding of both windings 10 and 5 is performed in an integrated process. In the embodiment of FIG. 1, the primary winding 10 is divided into two, but each of the divided windings is wound through the same process.

The film winding machine 14 and the conductor cutting machine 1
5 is controlled by the NC control device 16. That is, N
By the cutting command signal a output from the conductor cutting command means 16a of the C control device 16, the cutter of the conductor cutting machine 15 operates to cut the urethane-coated conductor 10a, and at the same time,
The cutting instruction signal a is also input to the winding start instruction means 16b of the NC control device 16, and the film winding machine 14 is operated by the winding start instruction signal b output from the winding start instruction means 16b to operate the film winding machine. The work of winding the insulating film 10b delivered from the drum 14a around the urethane-coated conductive wire 10a is started. At this time, the portion from the cut portion of the urethane-coated conductive wire 10a to the winding start portion of the insulating film 10b is the end line portion of the winding start end of the first or third layer of the primary winding 10, and this end line portion is , L1 in FIG. 4 required for soldering to the primary terminal pins 9a or 9b in FIG. 1 is set.

When the insulating film 10b is wound by the length shown by L2 in FIG. 4 necessary for the winding start portion of the first or third coil winding layer, the winding of the NC control device 16 of FIG. A winding end signal c is output from the end command means 16c, and the operation of the tape winding machine 14 is stopped. Next, when the urethane coated conductive wire 10a has been fed by the length L3 required to be wound a predetermined number of times in the first layer or the third layer without the insulating film 10b, the winding start command means 16b restarts. Winding start command signal b
Is output, and the winding of the insulating film 10b around the urethane coated conductive wire 10a is restarted.

This insulating film 10b is wound around the urethane-coated conductive wire 10a by a length L4 required for the winding end portion of the first or third layer. When this winding is completed, the winding end command means 16c outputs a winding end signal c, and the operation of the tape winding machine 14 is stopped.
From this point, when the urethane-coated conductive wire 10a is conveyed by the length L5 required for soldering the end wire portion of the winding end of the first or third coil winding layer, the cutting command signal a The cutter of the conductor cutting machine 15 operates to cut the urethane-coated conductor 10a, and one step is completed.
Hereafter, the same steps are repeated.

FIG. 5 is a schematic vertical sectional view of the essential part of another embodiment of the present invention. In this embodiment, the primary winding 10 and the secondary winding 5 divided into two are wound in two layers. The primary winding 10 is divided into two to form first and third coil winding layers, respectively. In each coil winding layer of the primary winding 10, the insulating film 10b is wound around not only the winding start end and the winding end end but also a winding back portion (intermediate portion) that changes the winding direction.

The insulating film 10b may be wound around both ends of the coil winding layer of the secondary winding 5 instead of the primary winding 10, or the insulating film 10b of each coil winding layer of both windings 10 and 5 may be wound. The same effect as described above can be obtained by winding the both ends. Further, in the above embodiment, the primary winding 10
Although the case where only the secondary winding 5 is divided into two has been described, only the secondary winding 5 or both of them 10 and 5 may be divided into two. Further, each winding 10, 5 may be divided into three or more. Both the primary winding 10 and the secondary winding 5 may be multi-divided.

[0024]

As described above, according to the transformer of the present invention, in at least one of the conducting wires of the primary winding and the secondary winding, there is a comparatively large potential difference between both windings or between the winding and the core. Since the insulating film is configured to be wound a predetermined number of times only on a large portion or on a predetermined portion requiring high insulation such as a portion required for safety standards, this insulating film allows each coil winding layer or A required creepage distance can be secured between the coil winding layer and the core. Therefore, the size can be reduced as compared with a conventional barrier tape or a conductor having a three-layer insulating coating layer, which secures a creepage distance. Further, since the existing expensive conductor wire or barrier tape having three layers of insulating coating layers is not used, the material cost is reduced, and the troublesome work of winding the barrier tape for each coil winding layer is unnecessary.
The manufacturing cost can be reduced as the assembling workability is improved.
Furthermore, since the insulating film is only partially wound around the conducting wire, a high degree of magnetic coupling can be obtained between the primary and secondary windings, and the desired performance of the transformer can be maintained.
Since no manual work such as peeling of the insulating coating layer for soldering is required, the assembly process can be automated.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a transformer according to an embodiment of the present invention.

FIG. 2 is an explanatory view showing a winding portion of an insulating film in the above-mentioned embodiment.

FIG. 3 is a schematic configuration diagram showing an example of an apparatus for manufacturing the transformer of the above embodiment.

FIG. 4 is an explanatory view showing a partially wound state of the insulating film by the above manufacturing apparatus.

FIG. 5 is a schematic vertical sectional view showing an essential part of another embodiment of the present invention.

FIG. 6 is a vertical sectional view showing an example of a conventional transformer.

FIG. 7 is a vertical sectional view showing another example of a conventional transformer.

[Explanation of symbols]

1 ... Bobbin, 5 ... Secondary winding, 6, 7 ... Core, 10 ... Primary winding, 10a ... Primary winding conducting wire, 10b ... Insulating film.

Claims (1)

[Claims] 1. A transformer in which a primary winding and a secondary winding are wound around a bobbin attached to a core so as to be overlapped in the radial direction of the bobbin, and high in at least one of the conductor wires of the primary winding and the secondary winding. Only in certain parts where insulation is required,
A transformer characterized in that an insulating film is wound a predetermined number of times.