JPH0747856Y2 - Small transformer - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small transformer for a power supply used in electronic circuits.

[0002]

2. Description of the Related Art Conventionally, in a small-sized transformer for a power source used in an electronic circuit, as shown in FIG. The secondary winding 55 and the secondary winding 56 are wound and E
The structure with the shaped core 57 attached, or as shown in FIG.
There is known a structure in which a primary winding 62 and a secondary winding 63 are coaxially wound around a bobbin 61 via an insulating tape 64 and an E-shaped core 65 is attached. However, the structure of FIG. 1 has a drawback that the electromagnetic coupling between the primary winding 55 and the secondary winding 56 is weak, resulting in a large power loss. Further, in the structure shown in FIG. 2, since the insulating tape 64 must be wound manually, the work efficiency is low and the manufacturing cost is high. Furthermore, in order to ensure the insulation between the primary winding 62 and the secondary winding 63 and increase the withstand voltage between both windings,
It is necessary to increase the number of windings of the insulating tape and increase the thickness of the layer, and therefore, there is a drawback that the size of the entire transformer becomes large.

[0003]

It is an object of the present invention to improve the above-mentioned conventional drawbacks and to ensure the insulation between the primary and secondary windings.
It is an object of the present invention to provide a small transformer which has a high withstand voltage, is miniaturized, and is easy to assemble.

[0004]

SUMMARY OF THE INVENTION According to the present invention, a drum core having a lower collar having a diameter larger than that of an upper collar, a primary winding wound around the drum core, a tubular portion, a flange portion, and a flare portion are provided. Is integrally formed, and 2 is provided between the flange portion and the flare portion.
A bobbin formed by winding the next winding and a ring core mounted on the outer periphery of the bobbin are coaxially arranged, and the tubular portion and the flare portion of the bobbin hold the upper and lower flanges of the drum core. The flange portion and the flare portion of the bobbin are in contact with the inner circumference of the ring core.

[0005]

Embodiment 1 An embodiment of the present invention will be described below.
3 and 4, reference numeral 1 denotes a drum core having an upper collar 2 and a lower collar 3, and the diameter of the lower collar 3 is larger than that of the upper collar 2. 4 is a primary winding wound around the drum core,
Reference numeral 5 is a bobbin integrally formed with a tubular portion 6, a flange portion 7 and a flare portion 8, 9 is a secondary winding wound between the flange portion 7 and the flare portion 8 of the bobbin, and 10 is a bobbin 5 A ring core mounted on the outer side of the base 11, a base provided with a winding guide groove 12 and a terminal pin 13, and a recess 14 formed in the flare portion 8 of the bobbin 5 for inserting a secondary winding. Here, the tubular portion 6 and the flare portion 8 of the bobbin 5 are sized to hold the upper flange 2 and the lower flange 3 of the drum core 1, respectively, when the bobbin is attached to the drum core. Further, the flange portion 7 and the flare portion 8 of the bobbin 5 are in contact with the inner circumference of the ring core 10. With this configuration,
The drum core 1 around which the secondary winding 4 is wound is attached to the base 11 by adhesion or the like, and the end of the primary winding is connected to the terminal pin 13 through the winding guide groove 12. Next, the bobbin 5 around which the secondary winding 9 is wound is attached from above the drum core 1. At this time, the tubular portion 6 of the bobbin 5 holds the upper flange 2 of the drum core 1, and the flare portion 8 holds the lower flange 3 of the drum core 1. The end of the secondary winding 9 is connected to the terminal pin 13 through the recess 14 and the winding guide groove 12. Furthermore, when the ring core 10 is attached to the bobbin 5, the flange portion 7 and the flare portion 8 of the bobbin 5 contact the inner circumference of the ring core 10,
Therefore, the drum core 1, the bobbin 5, and the ring core 10 are coaxially integrated, and these are mechanically and firmly coupled to each other. Further, since the primary winding 4 and the secondary winding 9 can be arranged coaxially and in close proximity to each other, the magnetic coupling between them becomes strong and the magnetic leakage loss is reduced. Further, since the primary winding 4 and the secondary winding 9 can be reliably insulated by the bobbin 5, the withstand voltage between both windings can be increased. In this embodiment, the position of the flange portion provided on the bobbin is determined so that the upper flange 2 of the drum core 1 and the upper surfaces of the ring core 10 are substantially horizontal. With this configuration, the height of the entire transformer can be reduced.

[0006]

Embodiment 2 FIG. 5 shows another embodiment of the present invention.
The flange portion 7 of the bobbin 5 is formed at the tip of the tubular portion 6, and a pot type core 15 whose upper surface is closed is used instead of the ring core.

[0007]

As described above, in the small transformer of the present invention, the primary winding is wound around the drum core having the lower collar having a diameter larger than that of the upper collar, and the tubular portion, the flange portion and the flare portion are wound. A secondary winding is wound around the outer periphery of a bobbin integrally formed with, the bobbin is attached to the outer periphery of the drum core, and further the outer peripheral ring core of the bobbin is attached to arrange these coaxially. Since the tubular portion and the flare portion of the bobbin hold the upper and lower flanges of the drum core, and the flange portion and the flare portion of the bobbin are in contact with the inner circumference of the ring core, the drum core , Bobbin,
A mechanical connection of the ring core is ensured. Further, since it is not necessary to wind an insulating tape around the insulation between the primary winding and the secondary winding, the assembling work becomes easy and the working efficiency is improved.
It is possible to ensure insulation between both windings. Further, since the electromagnetic coupling between the primary winding and the secondary winding is strengthened, it is possible to reduce the magnetic leakage loss and thus the power loss. Further, since the distance relationship among the drum core, the primary winding, the bobbin, the secondary winding, and the ring core can always be kept constant, there is an advantage that a product having uniform electrical performance can be mass-produced.

[0008]

[Brief description of drawings]

1 and 2 are sectional views showing the structure of a conventional transformer. FIG. 3 is an exploded perspective view showing an embodiment of a small transformer of the present invention, FIG. 4 is an assembled sectional view of the embodiment, and FIG. 5 is another embodiment of the present invention. It is an assembly sectional view showing an example.

[0009]

[Explanation of sign]

1 ... Drum core, 2 ... Upper collar, 3 ... Lower collar, 4
... Primary winding, 5 ... Bobbin, 6 ... Cylindrical part, 7
... Flange part, 8 ... flare part, 9 ... secondary winding, 10 ... ring core, 11 ... base, 12 ...
..Winding guide grooves, 13 ... Terminal pins, 14 ... Recesses, 15 ... Pot-type core

Claims (1)

[Scope of utility model registration request] 1. A flange comprising a drum core having a lower flange having a diameter larger than that of the upper flange, a primary winding wound around the drum core, a tubular portion, a flange portion and a flare portion, which are integrally formed. A bobbin formed by winding a secondary winding between the portion and the flare portion and a ring core mounted on the outer periphery of the bobbin are arranged coaxially, and the tubular portion and the flare portion of the bobbin form a drum core. A small transformer characterized in that the upper and lower flanges are held and the flange portion and the flare portion of the bobbin are in contact with the inner circumference of the ring core.