US1721379A - Magnetic core and method of manufacture - Google Patents

Description

Patented July 16, 1929.

unien STATES PATENT OFFICE;

' EHLERS, OF COPENICK, FALKENBEBG, OF BERLIN, GERMANY,

ASSIGNOBS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

iuaenn'nc oorm'ann uncrnon or MANUFACTURE;

. No Drawing. Applicationflled July 9, 1926, Serial-No. 121,490, and in Germany July 25, 1925.

Our present invention relates to magnetic.

cores such, forexample, as those employed ior telephone repeater coils or loading coils,

and similar purposes.

' Cores of this generaltype are practice made bywinding fine Wire into rings, by

one another is generally not necessary as the v f thm hlm of OXlClGfOIIIIBd on the wire Wlll furnish allot the insulation required. In the case of cores'inade up of powdered-mat rial. however, some insulation is required and this is usually supplied'by employing i'mthe body of-the core a mixture of magnetic and insulating material. It is-well rec-' ognized, however, that in any of these types of cores the magnet-icand insulating elements I cannot completelyfill the space occupied by. the core. N on-magnetic intermediate spaces ren'min which are especially injurious when located transversely to the magnetic field; These spacesmay reduce the effective permeability of the core to a considerable extent.

The object of ouninvention is to provide a .niethod whereby this disadvantage may largely be overcome. In carrying our invent1on into effect, we provide a way of filling these hollow spaces partially-or entirely with magnetic material in order to increase the cll'ective permeability. This may be accomplished by impregnating the core after itsmanufacture by means of a magnetic soluhull or .fuslon. In the-case of'a core made from pressed powdered material the impregnation is possible because of the factthat" hands this 18th day of June, 1926.

even after the material has been subjected to high pressure the mas-sis still permeated by a capillary network of hollow spaces.

As an impregnating medium colloidal so-' lutions of metallic iron or metallic. iron alloys or other magnetic materials in readily vaporizable liquids are suitable. Preferably the mass'should be repeatedly impregnated and dried. The core may in some cases be impregnated in fused baths of Heusler alloys, or such alloys may be added in the form of fine powdered material before it is assem bled, and after assembly this powder can be dispersed by heating' WVhat we claim as new and desire to secure by Letters Patent of the United States, is

1. The method of increasing-the permeability of magnetic cores formed of pressed powdered material which consists in filling hollow spaces in the core after. assembly by particles of magnetic material.

.2. The method of increasing the permeability of magnetic cores WhlCliCODSlStS in impregnating the core body after assembly by immersing it in a liquid containing magnetic material in a form capable of entering the spaces in the core. 4

3. The method of increasing the permeability of a magnetic core which consists in impregnating the core body after assembly in a colloidal solution of magnetic material and then vaporizing the liquid of the solution. a

4. The method of increasing the permeability of magnetic cores which consists in asscmbling the core and then impregnating the core body with a solution of magnetic material.

5.-The methodof increasing the permea- 8O bility of magnetic cores whichfconsists in first assembling the core, then nnmersmg the core 4 body n a. liquid containing magnetlc material in solution and then vaporizing the liquid of j v the solution.

' In w1tness whereof. we have hereto set our WALTHE'R EriLERsr FRITZ FALKENBERG.