The invention concerns method for manufacturing powder composite magnetic core and powder composite magnetic core designed for manufacture of magnetic circuits used in electrotechnical appliances, and especially those employed in electrical machines.

Inductive element and method for producing the same are already known from international patent application WO02/101763. Said powder composite is produced by mixing a ferromagnetic amorphous or nanocrystalline alloy powder with a ferromagnetic dielectric powder and a thermoplastic or duroplastic polymer, with dielectric ferromagnetic powder alloy equaling more than 55% by volume. Inductive element produced of dielectric ferromagnetic powder is characteristic in that in the mixture of powders, ribbons of ferromagnetic alloy are placed in the mixture of powders.

Known from their employment are magnetic cores or powder composite magnetic cores, which are manufactured as components from homogenous mass of compressed powder, wherein the compacted magnetic cores are thermally or chemically treated.

Method for manufacturing, according to the invention comprises the die being filled with first with soft magnetic powder, then with hard magnetic powder, wherein the filling sequence is repeated alternatingly at least once with soft magnetic powder and at least with hard magnetic powder, with the poured powder being bounded through compacting.

Favourably, the hard magnetic powder is mixed with insulating and bounding dielectric.

What is favourable is also that the die is being simultaneously filled with soft and hard magnetic powders along its walls.

According to the invention, the idea of powder composite magnetic core comprises at least two spaces, with at least one space is filled with soft magnetic material and at least one with hard magnetic material.

Favourably, at least one space should be filled with hard magnetic material placed within the space filled with soft magnetic powder.

What is also favourable is that at least one space is filled with soft magnetic material and at least one is filled with hard magnetic material. These spaces are located along lateral sides of the magnetic core.

Favourably, at least one layer of hard magnetic material is located along lateral sides of soft magnetic material, or at least one layer of hard magnetic material is located perpendicular to lateral sides of a component made of soft magnetic material.

Powder composite magnetic cores manufactured by the use of this innovative method are characterized by very good magnetic properties. The innovative method allows for manufacture of magnetic core configurations of any number of soft magnetic and hard magnetic layers. Main advantage of this innovative method is the possibility of manufacture of a dielectromagnetic-dielectromagnet type hybrid magnetic core through the use of powders exhibiting the desired properties in the filling process. Hybrid is formed during the process of filling the die with a proper powder. In case of cores or their more developed configurations, dielectromagnetic powder is used as layer which separates hard magnetic powder layers.

Embodiment of the invention w is presented in the drawing in which Fig. 1 illustrates powder composite magnetic core with one layer of soft magnetic material and one layer of hard magnetic material; Fig. 2 - powder composite magnetic core with three spaces of soft magnetic material and two spaces of hard magnetic material; Fig. 3 - sectional view of powder composite magnetic core with one layer of hard magnetic material located along lateral sides of a component made of soft magnetic material; Fig. 4 - powder composite magnetic core with two spaces of hard magnetic material located along lateral sides of a component made of soft magnetic material; Fig. 5 - demagnetization characteristics in function of magnetic field intensity, and Fig. 6 - maximal value of energy density for respective powder composite magnetic cores.

Method for manufacturing powder composite magnetic core comprises the die being filled with soft magnetic powder and then with hard magnetic powder. Layers of powders are bonded through the process of compacting, wherein hard magnetic powder is mixed with insulating and bonding dielectric before it is poured into the die.

Method for manufacturing powder composite magnetic core proceeds in the same way as in example 1, the difference being that the sequence of form filling is repeated three times with soft magnetic powder and twice with hard magnetic powder.

Method for manufacturing powder composite magnetic core proceeds in the same way as in example 1, the difference being that soft magnetic powder and hard magnetic powder are poured into the die simultaneously.

Powder composite magnetic core, manufactured as component made of compacted powder, has two spaces 1, 2, wherein one space is filled with soft magnetic powder 1, and second space is filled with hard magnetic material 2.

Powder composite magnetic core is manufactured as in example 4, the difference being that it is manufactured as a layered magnetic core and has two spaces filled with hard magnetic powder 2 located between three layers of filled with soft magnetic material 1.

Powder composite magnetic core is manufactured as in example 4, the difference being that it is manufactured as a cylinder, whose soft magnetic material space 1 is located within hard magnetic material space 2.

Powder composite magnetic core is manufactured as in example 6, the difference being that it is manufactured as a cubicoid.

Powder composite magnetic core is manufactured as in example 4, the difference being that it is manufactured as a cubicoid, wherein soft magnetic material-filled spaces 1 are located alternately with hard magnetic material-filled spaces along the lateral sides of rectangular prism.

Magnetic properties of new powder composite magnetic cores are illustrated with diagrams, first of which presents the dependence of magnetic field intensity H in function of demagnetization jB, and the second - maximum values of energy density BH_max for selected types of A, B, C and D magnetic cores.

It is clearly visible that maximum value of energy density for A, B, C and D magnetic cores depends on the thickness and the number of layers of the tested A, B, C and D magnetic cores. Magnetic cores A and B are manufactured as layered magnetic cores and each has one hard magnetic material-filled layer 2 located between two spaces filled with soft magnetic material 1. Magnetic cores A and B differ as far as the thickness of spaces is concerned. Magnetic core C is manufactured as a layered magnetic core, as in example 2. Magnetic core D is also manufactured as a layered magnetic core, the difference being that it has three spaces filled with hard magnetic material 2 located between four soft magnetic material-filled spaces 1.