JPS6154608A - Transformer - Google Patents

Abstract

PURPOSE:To obtain the transformer which is safe to a lightening stroke by a method wherein the primary winding is wound around the inside bobbin having a flange part on both ends, said bobbin is inserted into the outside bobbin, having a flange part on both sides, whereon a secondary winding is wound around, and the flange parts having a saw tooth-like roughened surface are adhered using insulated resin. CONSTITUTION:A flange part 5 whereon a plurality of connection pins 11 are erected and a flange part 3 having the outside diameter a little smaller than the flange parts 5 are formed on both end parts of an inside bobbin 1, having almost square-shaped cross- section, whereon the primary winding 8 will be wound around. Also, a flange part 7 is provided on both end parts of an outside bobbin 2, whereon a secondary winding 9 will be wound around, through the intermediary of the receptacle 4 where flange parts 3 and 6 are superposed, and a plurality of connection pins 11 are protruded on the flange part 7. Then, an inside bobbin is inserted into the outside bobbin 2, and they are formed in one body. At this time, saw tooth-like recesses and projections 12-15 are provided on the mutually contacted surface of said flange parts, and each flange part is adhered by coating insulative resin 16 such as silicon and the like. Subsequently, a core 10 is provided on the outer circumference of the bobbins by performing the commonly used method.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a small transformer equipped with an iron core, particularly to a winding frame (bobbin) of the transformer, which ensures more reliable insulation between the iron core and the winding.

Structure of the conventional example and its problems In the conventional transformer, as shown in Fig. 5, the inner bobbin 1
and an outer bobbin 2, the inner bobbin 1 is fitted into the winding drum of the outer bobbin 2, and the primary winding is wound on the inner bobbin 1, and the secondary winding is wound on the outer bobbin 2. The insulation between the secondary windings and between the primary winding and the iron core depends on the wall thickness of these bobbins and the spatial insulation of the space plane.

Details of such a conventional transformer will be further explained with reference to FIG. In the same figure, the collar part 3 at one end of the inner bobbin l is fitted inside the outer bobbin 2 and overlapped with the receiving part 4 provided at one end of the outer bobbin 2. The collar portion 5 is overlapped with the tail portion 6 of the outer bobbin 2, and these overlapping surfaces are bonded by impregnating varnish. In addition, 7 is the collar of the outer bobbin, 8 is the primary winding wound on the inner bobbin, 9 is the secondary winding wound on the outer bobbin, 10 is the iron core, and 11 is the terminal embedded in each bobbin. It's a pin. Here, the space insulation between the iron core 10 and the primary winding 8 is achieved between A and B indicated by dotted arrows in the figure, and is usually done by impregnating with varnish as described above. These voids are filled to strengthen the insulation. However, when an electric shock is applied to the transformer using the test circuit shown in Figure 7, the varnish impregnation treatment does not completely fill the gaps between the overlapping surfaces, causing leakage between the primary winding and the iron core. This causes problems such as layer short-circuiting of the primary winding. That is, in FIG.
is an impulse generator designed for lightning surges, and when an impulse is applied to the antenna terminal while the transformer T is operating normally, the core 1 of the transformer as shown in the figure
This means that a high voltage is applied between 0 and the primary winding 8,
A state where leakage easily occurs between the iron core 10 and the primary winding 8 occurs. The conventional transformer described above does not have a complete insulation function against such electric shocks, and a layer short-circuit occurs in the primary winding.

OBJECTS OF THE INVENTION The object of the present invention is to eliminate such drawbacks and provide a transformer that is safe against lightning shock.

Structure of the Invention The present invention provides an overlapping surface between a collar portion of an inner bobbin fitted inside a winding drum of an outer bobbin and a receiving portion of a row-side bobbin superimposed thereon, and the other tail portion of the inner bobbin. An uneven surface is formed on the overlapping surfaces of the collar portion of the outer bobbin and the outer bobbin which are overlapped thereon, and an insulating resin is applied to the uneven surfaces to bond these overlapping surfaces together.

DESCRIPTION OF EMBODIMENTS FIG. 1 is a sectional view of the main parts of a transformer according to the present invention, and FIG. 2 is a perspective view of an inner bobbin and an outer bobbin.

In these figures, 1 is an inner bobbin, which has flanges 3 and 5 at both ends thereof. 2 is the outer bobbin, and the inner bobbin l
A receiving part 4 and a collar part 7 are provided on one end of which the collar part 3 of the inner bobbin is overlapped, and the other collar part 5 of the inner bobbin is fitted on the other end thereof. A collar portion 6 is provided which is overlapped with the flange portion 6, and each of these overlapping surfaces forms respective saw-shaped uneven surfaces 12 to 15. The primary winding 8 is wound on the inner bobbin 1, the secondary winding 9 is wound on the outer bobbin 2, the lead wire of each winding is connected to the terminal pin 11 provided on each bobbin, and one of the inner bobbins is connected. Insulation such as silicone resin is applied to the uneven surface of the overlapping part of the collar part 3 and the receiving part 4 of the outer bobbin, and the uneven surface of the overlap part of the other collar part 5 of the inner bobbin and the collar part 6 of the outer bobbin, respectively. After applying the resin 1B, insert the collar 3 of the inner bobbin 1 inside the winding drum of the outer bobbin 2, adhere the outer bobbin 2 and the inner bobbin l at their overlapping surfaces, and attach the iron core 10 to this. Install and assemble the transformer. FIG. 3 is a perspective view of the assembled transformer.

As shown in the embodiment of FIG. 1, the iron core 10 and the primary winding vJ,
The space insulation between 8 is the overlapping part of the receiving part 4 of the outer bobbin 2 and the collar part 3 of the inner bobbin 1, and the overlapping part of the collar s5 of the inner bobbin 1 and the tail part 6 of the outer bobbin 2. These parts form respective saw-shaped uneven surfaces, and the overlapping parts are bonded by applying an insulating resin such as silicone resin.

Note that the uneven surface of the overlapping portion described above may be formed by a plurality of uneven grooves 17 as shown in FIG.

Effects of the Invention As shown in the embodiments described above, in the present invention, the overlapping portion of the inner bobbin and the outer bobbin has an uneven surface, and an insulating resin is further applied thereon and bonded. The adhesive force is strengthened by making the adhesive area wider than the bonding method using varnish impregnation as explained in 2. Also, the spatial insulation distance between the primary winding and the iron core becomes longer, which increases the dielectric strength between the primary winding and the iron core. This further increases reliability, and since the insulating resin is only applied to the bonding surfaces of the inner and outer bobbins, the amount of resin used is smaller than when the entire transformer is impregnated with insulating resin. Industrial effects such as these can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of an embodiment of the transformer of the present invention, FIG. 2 is a perspective view of the inner and outer bobbins of the transformer of the present invention, FIG. 3 is a perspective view of the assembled transformer, and FIG. 4
5 is an exploded perspective view of the bobbin of a conventional transformer, FIG. 6 is a sectional view of the main part of a conventional transformer, and FIG. 7 is a sectional view of the main part of a conventional transformer. A surge test circuit is shown. ■...Inner bobbin 2...Outer bobbin 3.5...
・Inner bobbin collar 4...Receptacle 6.7...Outer bobbin collar 8...Primary winding 9...Secondary @
Wire 10... Iron core 12-15... Uneven surface 16
...Name of Insulating Resin Agent Patent Attorney Etsuji Yoshizaki Figure 3 Figure 4 C Figure 6

Claims (1)

[Claims] It consists of an inner bobbin having an iron core and around which a first winding wire is wound, and an outer bobbin that fits outside the inner bobbin and around which a second winding wire is wound, and the inner bobbin has one end thereof. The outer bobbin has a collar portion that fits inside the winding drum portion of the outer bobbin and a collar portion that overlaps the collar portion of the outer bobbin at the other end, and the outer bobbin has one end that fits inside the winding drum portion. The collar of the inner bobbin and the outer bobbin have a receiving part on which the collar of the combined inner bobbin overlaps, and a collar on the other end of which the collar of the other end of the inner bobbin is overlapped. An uneven surface is formed on the overlapping surface with the receiving part and the overlapping surface between the other brim of the inner bobbin and the outer bobbin brim, and an insulating resin is applied to these uneven surfaces to separate each overlap. A transformer characterized by having mating surfaces glued together.