GB1562276A - Method of making a magnetic circuit including an air gap - Google Patents

Description

(54) A METHOD OF MAKING A MAGNETIC CIRCUIT INCLUDING AN AIR GAP (71) We, VOGT GMBH & Co., KG, a Germany Company, of Erlautal 7, D 8391 Erlau, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to a method of making a magnetic circuit including an air gap and also to a magnetic circuit made by the method.

In particular, the invention concerns a method of connecting together two core parts of a magnetic circuit so as to provide a gap of a predetermined width between confronting end faces of the parts.

It is known for air gaps of a specific size to be produced in magnetic circuits (e.g. in transformers having laminated or ferrite cores) by placing an intermediate layer of a selection thickness between confronting surfaces of component parts of the core, such as arms, and clamping the core parts together mechanically.

Furthermore, it is known for the said intermeditae layer to be adhered on both sides to the arms, so that a mechanical clamping device is unnecessary.

It is an object of the invention to provide an improved method of making a magnetic circuit core having a gap of a predetermined width.

In accordance with the invention there is provided a method of connecting together two core parts of a magnetic circuit so as to provide a gap of a predetermined width between confronting end faces of the parts, in which the confronting end faces are fixed to each other by an adhesive material and at least one spherical body of a nonmagnetic material and having a diameter equal to the said predetermined gap width is in the adhesive material.

Examples of the method according to the invention are hereinafter described with reference to the single figure of the accompanying drawing which is a diagrammatic elevational view, to an enlarged scale, of part of a magnetic circuit made by the method of the invention.

References 1 and 2 are parts of a magnetic core which are required to be connected together so as to provide a gap G therebetween of a predetermined width. This gap is commonly called an air-gap although, as in the present invention, it is filled with non-magnetic material. The core parts 1 and 2 may be parts of a transformer core and may be of a ferrite material or may comprise laminations of a ferromagnetic material.

The size of the gap G is determined by the diameter of a spherical body 3 of a nonmagnetic material, the preferred material being glass.

To connect the parts 1 and 2 together the body 3 is placed in a mass of an adhesive 4, preferably an epoxy resin compound, and the combination of the adhesive and the body is placed on the end of one or both of the parts 1 and 2 so that the body 3 becomes attached to one or both of the parts. Alternatively, the adhesive 4 may be applied to the end of one or both of the parts 1 and 2 and the body 3 be subsequently inserted in the adhesive. However, which method is used, the two parts 1 and 2 are subsequently moved towards each other until further movement is prevented by the body 3. Thus, the diameter of the body 3 determines the size of the gap G. On curing of the adhesive 4 the parts 1 and 2 are firmly connected to each other and are spaced apart by the gap G.

Obviously, a further spherical body or bodies of non-magnetic material. e.g. glass, having the same diameter as the body 3 may be placed in the gap, if desired, and together serve to determine the gap width, each body being held in place by the adhesive material 4.

In one advantageous construction of the magnetic core, as shown in the drawing, a plurality of spherical bodies 5 of a nonmagnetic material, e.g. glass, are incorporated with the adhesive material 4 to serve as a filler material in the gap, these bodies 5 all having a diameter less than that of the body 3.

The spherical bodies 3 and 5 may be obtained by standard screening processes to obtain bodies of the required diameter.

WHAT WE CLAIM IS: 1. A method of connecting together two core parts of a magnetic circuit so as to provide a gap of a predetermined width between confronting end faces of the parts, in which the confronting end faces are fixed to each other by an adhesive material and at least one spherical body of a nonmagnetic material and having a diameter equal to the said predetermined gap width is in the adhesive material.

2. A method, according to Claim 1, in which at least one further said spherical body is in the adhesive material.

3. A method, according to Claim 1 or Claim 2, in which a plurality of spherical bodies of a non-magnetic material and having a diameter or diameters less than that of the said spherical body, are in the adhesive material.

4. A method, according to any preceding claim, in which the material of the said spherical body and the said plurality of spherical bodies is glass.

5. A method, according to any preceding claim, in which the adhesive material is an epoxy resin compound.

6. A method, according to any preceding claim, in which the core parts are of a ferrite.

7. A method of connecting together two core parts of a magnetic circuit substantially as hereinbefore described with reference to the accompanying drawing.

8. A magnetic circuit core made by a method according to any preceding claim.

9. A transformer having a magnetic circuit core according to Claim 8.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (9)

**WARNING** start of CLMS field may overlap end of DESC **. each body being held in place by the adhesive material 4. In one advantageous construction of the magnetic core, as shown in the drawing, a plurality of spherical bodies 5 of a nonmagnetic material, e.g. glass, are incorporated with the adhesive material 4 to serve as a filler material in the gap, these bodies 5 all having a diameter less than that of the body 3. The spherical bodies 3 and 5 may be obtained by standard screening processes to obtain bodies of the required diameter. WHAT WE CLAIM IS:

1. A method of connecting together two core parts of a magnetic circuit so as to provide a gap of a predetermined width between confronting end faces of the parts, in which the confronting end faces are fixed to each other by an adhesive material and at least one spherical body of a nonmagnetic material and having a diameter equal to the said predetermined gap width is in the adhesive material.

2. A method, according to Claim 1, in which at least one further said spherical body is in the adhesive material.

3. A method, according to Claim 1 or Claim 2, in which a plurality of spherical bodies of a non-magnetic material and having a diameter or diameters less than that of the said spherical body, are in the adhesive material.

4. A method, according to any preceding claim, in which the material of the said spherical body and the said plurality of spherical bodies is glass.

5. A method, according to any preceding claim, in which the adhesive material is an epoxy resin compound.

6. A method, according to any preceding claim, in which the core parts are of a ferrite.

7. A method of connecting together two core parts of a magnetic circuit substantially as hereinbefore described with reference to the accompanying drawing.

8. A magnetic circuit core made by a method according to any preceding claim.

9. A transformer having a magnetic circuit core according to Claim 8.