JPS5941813A - Surface shield type molded transformer - Google Patents

Abstract

PURPOSE:To ground a transformer positively without exfoliating the shield layer consisting of a metal-sprayed film even when external force is applied to a ground wire by coating the surface exposed from the insulating resin layer of a terminal fitting for ground buried in the insulating resin layer of a molded coil with one part of the shield layer. CONSTITUTION:When a molded coil 2 is manufactured by coating coil conductors 3 with an insulating resin layer 4 through a cast method, a terminal seat 11 as one part of the terminal fitting for ground is set previously to a die, a resin is injected around the seat 11 and cured, and the seat is buried and fixed in the insulating resin layer 4. A metal, such as aluminum, zinc or the like is flame- sprayed on the surface of the molded coil 2 except the peripheries of coil terminals 5, 6 to form the shield layer 7 of approximately 20-200mum thickness, and the surface exposed from the insulating resin layer 4 of the terminal seat 11 is also coated with the metal-sprayed film to connect the terminal seat 11 and the shield layer 7. The ground wire 9 is connected to the shield layer 7 by a bolt 12 for clamping a ground wire terminal screwed to the terminal seat 11.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a surface-shielded molded transformer that is safe even if a human body touches the surface of the molded coil during energization, and particularly to a terminal structure for grounding the shield layer of the molded coil.

The surface of the molded coil is covered with an insulating resin layer, but because of the capacitance that exists between the resin layer and the ground, generally when a molded transformer is energized, the surface of the molded coil will have a considerable high voltage. It has a potential and there is a risk of electric shock if the human body touches it. As a countermeasure, the surface of the resin layer, excluding the area around the terminals of the mold core, has good adhesion to the resin layer.

It was previously proposed (Japanese Patent Application No. 56-179670) to provide a shield layer made of chemically stable metal spray coating such as aluminum or zinc and to ground this shield layer.

Figures 1 to 3 are diagrams showing this surface shield type molded transformer, where ■ is an iron core, 2 is a molded coil combined with this, 3 is a coil conductor, 4 is an insulating resin layer, and 5 and 6 are coils. Terminals 7 are an insulating resin layer 4 excluding the periphery of these terminal parts.
A shield layer consisting of a metal sprayed coating deposited on the surface of the
8 is a grounding terminal fitting, 9 is a grounding wire connected to this, and the other end of the grounding wire 9 is an iron core fastening fitting 10 at ground potential.
etc., and ground the shield layer 7.

In such a surface shield type molded transformer, the method for grounding the shield layer is to connect the ground wire 9 to the terminal fitting 8 soldered to the shield layer 7 with solder 4 as shown in FIGS. 2 and 3. Ordinarily, a method of connecting the ground line 9 to the shield layer 7 or a method of directly attaching the ground line 9 to the shield layer 7 is considered. However, in these methods, the metal spray coating that forms the shield layer is very thin, measuring 20 to 200) 1 m.
If an external force is applied to the grounding wire, there is a risk that the shield layer will peel off, making it unsuitable for surface-shielded molded transformers that require grounding reliability.

Therefore, an object of the present invention is to provide a surface-shielded structure that improves the reliability of the grounding of the shield layer and ensures safety. By applying a part of the shield layer made of a metal spray coating to the surface exposed from the insulating resin layer of the terminal fitting, the shield layer is prevented from peeling off due to external force, and grounding is ensured. This is how it was done.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 9.

As shown in FIGS. 4 and 5, when making a molded coil 2 by covering a coil conductor 3 with an insulating resin layer 4 by casting, a terminal seat 11, which is a part of the grounding terminal fitting, is pre-plated with metal. Set it in a mold and inject resin around it,
It is cured and embedded and fixed in the insulating resin layer 4. Terminal seat 1
The best place for embedding No. 1 is near the coil terminals 5 and 6, which have thick resin layers, and at the bottom of the coil where it is easy to connect the ground wire.

6 and 7 on the surface of this molded coil 2.
As shown in the figure, metal such as aluminum or zinc is thermally sprayed to a thickness of 20 to 200 μm, except for the areas around the coil terminals 5 and 6.
A shield layer 7 of about n thickness is formed.

At this time, a metal spray coating is also applied to the surface of the terminal seat 11 exposed from the insulating resin layer 4 to connect the terminal seat 1 and the shield layer 7. The grounding wire 9 is connected to the terminal seat 1 as shown in FIG.
It is connected to the shield layer 7 by a ground wire terminal tightening port 12 screwed into the ground wire terminal 1 .

As shown in the schematic diagram in Figure 8, it is most desirable for the terminal seat 1■ to have a circular cross section in terms of cost and to prevent stress concentration in the resin layer 4. Any shape is acceptable as long as it does not cause stress to concentrate on the layer 4. The surface of the terminal seat 11 exposed from the resin layer 4 is flush with the resin layer 4 except for the central protrusion 14 in which the screw hole 13 is provided, and a shield layer made of a metal sprayed coating is applied to this part and the surface of the resin layer 4. 7 is deposited. The surface of the part embedded in the resin layer of the terminal seat 11 is roughened by dry blasting etc. in order to improve adhesion with the resin layer, and the same treatment is applied to the part to be covered with the shield layer 7. It is a good idea to apply

- Figure 9 shows the connection state of the ground wire. Ground wire terminal 16
is fixed to the terminal base 11 by a tightening bolt 12 and a spring washer 15 screwed into a 6-hole 13, but the metal spray coating that forms the shield layer 7 has a thickness of 20 to 200 μm.
and very thin (because it is not strong enough, the shield layer 7
A washer 8 which is slightly thicker than the height of the protruding part 14 of the terminal base is interposed between the part attached to the terminal base 11 and the ground wire terminal 16, and when the washer 8 is tightened to press down the shield layer, the shield layer 7 is It can prevent damage and improve grounding reliability. As the grounding wire 9, it is desirable to use a highly flexible braided wire in order to avoid applying excessive force to the molded coil. The other terminal J7 of the ground wire is fixed to a ground terminal provided on the core fastener 10, as shown in FIG. 1, and the shield layer 7 is grounded.

As explained above, according to the present invention, a part of the shield layer made of a metal spray coating is applied to the surface exposed from the insulating resin layer of the grounding terminal fitting embedded in the insulating resin layer of the molded coil. The grounding terminal fitting is firmly fixed to the molded coil, and even if an external force is applied to the grounding wire, the shield layer will not peel off and the grounding can be achieved reliably, making the surface-shielded molded transformer highly safe. can get.

[Brief explanation of the drawing]

Figures 1 fa) and (b) are front and side views of a surface-shielded molded transformer, Figure 2 is a perspective view of a shielded molded coil according to the prior art, and Figure 3 is its A-A'
A cross-sectional view, FIG. 4 shows a thermal spraying molded coil according to the present invention.
A perspective view of 'iiiI, FIG. 5 is a cross-sectional view of B-B,
FIG. 6 is a perspective view of the molded coil according to the present invention after thermal spraying, FIG. 7 is a sectional view taken along line cc', and FIG. ) is a side view, No. 9
The figure is a sectional view showing the connection state of the ground wire. 1: Iron core 2: Molded coil 3: Coil conductor 4 Two insulating resin layers 5.6: Coil terminal 7:
Shield layer 9: Grounding wire 11: Terminal seat which is part of the grounding terminal fitting 12: Grounding wire terminal tightening bolt 16, J-bu: Grounding wire terminal 18; Washer agent Patent attorney Junnosuke Nakamura i1 Figure 12 Leap Figure 3 57 - Figure 4 1'5 Figure 16 Figure 7

Claims (1)

[Scope of Claims] (1.) In a surface-shielded molded transformer constructed by combining a molded coil with an iron core, in which a shield layer made of a metal sprayed coating is provided on the surface of an insulating resin layer, except for the periphery of the coil terminal portion. , a part of the terminal fitting for grounding the shield layer is embedded in an insulating resin layer of a molded coil, and a part of the shielding layer is adhered to the surface of the terminal fitting exposed from the insulating resin layer. surface shield type molded transformer. +2+ All terminal fittings for the terminals listed in +iii - A terminal seat that is embedded in the insulating resin layer of the lead coil and a part of the shield layer listed in +iif is adhered to the surface exposed from the insulating resin layer, and the y:j4 child seat. Claim (1) comprising: a ground wire terminal tightening bolt screwed into the ground wire terminal; and a washer interposed between the ground wire terminal and a part of the shield layer applied to the terminal base (+iif). Surface shield type molded transformer.