JP7478166B2 - Inductive component and method for manufacturing the same - Google Patents

Description

The present invention relates to a method for manufacturing inductive components with high power density and good inductance with very good thermal conductivity.

In the manufacture of conventional transformers, a magnetic core is surrounded in a known manner by two electrical conductors with an unequal number of windings, e.g. copper wire windings. The electrical conductors are then surrounded by a covering material that connects between the magnetic core, which is surrounded by the windings, and the housing. During operation of the transformer, power losses occurring in the magnetic core or in the windings are dissipated through the covering material into the housing. This reduces the power density of conventional transformers.

In contrast, the inductive component according to the invention as defined in claim 1 is characterized by a high power density. This is achieved in that due to the construction of the inductive component, a high magnetic permeability (μ _R =2-4 or 10-500) can be achieved, which in turn increases the leakage inductance, which in addition allows the integration of a resonant inductance without significantly impairing the efficiency and thus the power density of the inductive component. Furthermore, due to the high thermal conductivity and very good power density, the installation space of the inductive component can be reduced. According to the invention, the inductive component comprises a copper wire winding and a covering material surrounding the copper wire winding. According to the invention, it is also possible to use two or more copper wire windings, or but one copper wire winding and at least one further winding of electrically conductive material. The number of windings then depends on the application of the inductive component. Here, the copper wire winding can be, for example, a free-form copper wire winding, the shape and form of which are essentially unlimited. A particularly suitable shape is a toroidal winding.

The covering material comprises a matrix and at least one first filler, i.e. only the first filler may be present or, however, a mixture of the first filler with one or more further fillers may be present. Here, the first filler and possibly further fillers are dispersed in the matrix, the resulting composite material provides a certain mechanical stability, and the matrix connects the copper wire winding with, for example, surrounding components. Here, the matrix comprises at least one selected from alumina cement, phosphate cement, SiO ₂ , MgO, and reactive alumina. These are water-solidified chemical compounds or mixtures of these compounds, not sintered ceramic materials. It is assumed that this makes it possible to prevent an increase in the permittivity at high permeability. Inductance may then be provided by a first filler contained in the matrix, the first filler comprising at least one soft magnetic powder. Here, the first filler may comprise only soft magnetic powder or a mixture of two or more soft magnetic powders.

In addition to very good magnetic properties, the inductive component also has high thermal conductivity and a low loss factor of dielectric constant. For example, the thermal conductivity of the coating material used according to the invention is 5-8 W/mK, which is due in particular to the use of alumina cement, phosphate cement, SiO ₂ , MgO or reactive alumina. The inductive component can also be constructed without a conventional magnetic core, thus reducing material costs and component manufacturing costs.

The dependent claims show preferred improvements of the invention.

The soft magnetic powder is advantageously selected from carbonyl iron powder and ferrite powder, since they have very good induction properties, i.e. they can be used either alone or, however, in the form of a mixture.

According to a further advantageous refinement, the coating comprises at least one polymer. For example, the thermal properties of the coating, such as the shrinkage rate or the thermal conductivity, can be advantageously influenced by using one or more polymers. Also, the adhesion of the coating to surrounding components, such as the housing, can be improved by using polymers. Particularly suitable polymers in this case are thermoplastic polymers.

Preferred polymers are acrylic esters, copolymers of ethylene and vinyl esters, copolymers of acrylic esters, methacrylic esters and styrene, copolymers of ethylene and vinyl acetate, and methyl silicone resins.

To improve the properties of the coating, the coating advantageously comprises at least one second filler, where this second filler can provide additional functionality to the coating. Here, only the second filler or, however, a mixture of two or more second fillers can be used. The second filler preferably comprises Al ₂ O ₃ , since it has very good thermal conductivity.

In order to provide good mechanical stability and at the same time high thermal conductivity and good magnetic permeability, the total mass of the matrix relative to the total mass of the coating is 5-25% by mass, where alumina cement, phosphate cement, SiO ₂ , MgO or reactive alumina form a very fine microstructure with grain sizes up to 200 μm, which contributes to the high stability and very good thermal conductivity of the matrix.

In order to optimize the functionality of the coating material, and in particular to improve its electrical conductivity and thermal conductivity, the combined mass of the first and second fillers relative to the total mass of the coating material is in particular 75-95% by mass.

With a view to maximizing the inductive properties of the inductive component, especially when using free-form copper wire windings without a magnetic core surrounded by copper wire windings, the total mass of the first filler relative to the total mass of the first and second fillers is preferably 75-95 mass %. That is, in addition to the first filler, only a small proportion of the second filler is contained in the matrix and thus also in the coating. For this reason, the proportion of soft magnetic powder is very high. As a result, a very good magnetic permeability is achieved.

According to a further advantageous refinement, the inductive component comprises a magnetic core. The copper wire winding thus surrounds the magnetic core at least partially or at least in sections. The magnetic core can be, for example, a ferrite core or a magnetic powder core with a polymer matrix or a sintered magnetic powder core, in particular configured as a ferrite core.

In the embodiment using the magnetic core described above, the total mass of the soft magnetic powder relative to the total mass of the first filler and the second filler is preferably 1 to 50 mass %. This allows the inductive component to have high magnetic permeability even if the total mass of the soft magnetic powder is reduced. It is possible to increase leakage inductance and integrate resonant inductance while maintaining a low dielectric constant.

In addition, in this embodiment using a magnetic core, it is advantageous from the viewpoint of the thermal conductivity of the coating material and therefore of the inductive component that the total mass of the second filler, particularly Al ₂ O ₃ , is 50 to 99 mass % relative to the total mass of the first filler and the second filler.

The induction component, and in particular the coating material, is advantageously free of Portland cement, i.e. no Portland cement is added or used during the production of the induction component. The total mass of Portland cement is therefore approximately 0% by mass relative to the total mass of the coating material and thus also of the induction component. Compared to the matrix according to the invention, Portland cement has the disadvantage of containing many impurities which, although acceptable for load-bearing components, significantly impair the properties for electronic applications, in particular for induction components. Furthermore, Portland cement has a significantly lower thermal conductivity than aluminous cement, phosphate cement, SiO ₂ , MgO or reactive alumina, which is believed to be due to the chemical structure of the individual matrix phases.

Furthermore advantageously, the first and second fillers are not sintered. This provides the advantages of high magnetic permeability and high thermal conductivity as well as the advantages of energy saving in production.

The inductive component can be configured, for example, as a coil and, for this purpose, in particular comprises a copper wire winding. Due to its very good inductive properties and thermal conductivity, the inductive component according to the invention is configured, in particular, as a transformer and, for this purpose, comprises a copper wire winding and at least one further conductive winding, which can also be configured as a copper wire winding.

Similarly, according to the invention, a method for producing an induction component is described. This method comprises the steps of mixing a matrix material with at least one first filler, water and, optionally, at least one flow agent, while producing a slurry. A slurry is here understood to be an unset, unhardened, more or less flowable or at least moldable mass.

The fluidizing agent in the sense of the present invention can be, for example, a modified polycarboxylic acid ether, which can be used, for example, at 0.1 to 2% by weight relative to the total weight of the slurry.

The matrix material then comprises at least one selected from non-hardened alumina cement, non-hardened phosphate cement, non-hardened SiO ₂ , non-hardened MgO and non-hardened reactive alumina. The first filler also comprises at least one soft magnetic powder. Mixing can be performed, for example, by stirring with a suitable stirrer. The resulting slurry is then placed around the copper wire winding so that the slurry surrounds as much of the entire surface of the copper wire winding as possible, but at least the outer periphery of the copper wire winding. The slurry is then solidified by at least partial hardening of the matrix material with water at a temperature in the range of 50 to 150° C. This hardening step can be performed, for example, in an oven. Sintering at temperatures above 200° C. is not performed. Hardening removes most of the previously used flow agent, which is then virtually undetectable.

The present invention provides a coating material within the meaning of the present invention, as already described above. The degree of hardening of the matrix material can be adjusted by the amount of water added. The appropriate amount of water can be found by simple experimentation.

The method according to the invention is easy and inexpensive to implement and allows the production of inductive components with high magnetic permeability (μ _R =2-4 or 10-500), high leakage inductance and integrated resonant inductance with little or no increase in the dielectric constant. Furthermore, the components produced by the invention are also characterized by high thermal conductivity, so that the inductive components are highly efficient and have excellent power density.

The advantages, benefits, and improvements described for the inductive components of the present invention also apply to the manufacturing method for the inductive components of the present invention.

To improve mechanical properties, the method may further include a step of annealing the matrix material after hardening, preferably at a temperature in the range of 100-150°C.

Advantageously, the method may also include a step of surrounding the magnetic core, in particular configured as a ferrite core, with a copper wire winding. In this embodiment, the copper wire winding is therefore not present as a free-form copper wire winding but surrounds the magnetic core. For this reason, the coating material is arranged around the copper wire winding surrounding the magnetic core, in particular not inside the copper wire winding.

The following describes an embodiment of the present invention in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of the induction component according to the first embodiment. FIG. 11 is a cross-sectional view of an induction component according to a second embodiment.

The figures show only the essential features of the invention. All other features have been omitted for clarity. Also, identical reference numbers refer to identical components.

Figure 1 shows a cross-sectional view of an induction component 1 according to a first embodiment. The induction component 1 includes a housing 2 in which a magnetic core 4 is disposed, surrounded on all sides by copper wire windings 3. Here, the copper wire windings 3 are wound directly around the magnetic core 4.

The magnetic core 4 is, for example, configured as a ferrite core, or as a magnetic powder core with a polymer matrix, or as a sintered magnetic powder core, preferably configured as a ferrite core. The magnetic core 4 and the copper wire winding 3 surrounding the magnetic core 4 are arranged in the housing 2. Between the housing 2 and the copper wire winding 3, a coating material 8 is arranged, which provides a connection between the copper wire winding 3 and the housing 2.

The coating material 8 includes a matrix 5, a first filler 6, and a second filler 7, where the first filler 6 is a soft magnetic powder such as carbonyl iron powder or ferrite powder, and the second filler 7 is Al ₂ O _3. The first filler 6 and the second filler 7 are dispersed in the matrix 5 and are of the non-sintered type.

The matrix 5 comprises at least one selected from alumina cement, phosphate cement, SiO ₂ , MgO and reactive alumina. These compounds or mixtures of these compounds are present in a form at least partially hardened in water at 50-150° C. and are not sintered. The matrix 5 therefore forms a microcrystalline network of particles with a maximum size of 200 μm, in which the fillers 6, 7 are homogeneously distributed. The coating material 8, and thus also the derivative component 1, does not contain Portland cement.

The total mass of the matrix 5 relative to the total mass of the coating material 8 is 5 to 25 mass%.

The total mass of the first and second fillers 6, 7 relative to the total mass of the coating material 8 is 75 to 95 mass%, and the ratio of the first filler 6, i.e., the soft magnetic powder, to the total mass of the first filler 6 and the second filler 7 is advantageously 1 to 50 mass%. As a result, since the ratio of the second filler 7 is high, particularly high thermal conductivity is obtained with good magnetic properties.

The inductive component 1 is characterized by high power density and high efficiency due to the use of the coating material 8. That is, the inductive component 1 has high leakage inductance and resonant inductance with high magnetic permeability (μ _R =2-4 or 10-500) without significantly increasing the dielectric constant. Furthermore, the coating material 8 has a high thermal conductivity, which further increases the power density of the inductive component 1.

Figure 2 shows a cross-sectional view of an inductive component 10 according to a second embodiment. The inductive component 10 differs from the inductive component 1 from Figure 1 in that it does not have a magnetic core. The copper wire winding 3 is therefore in the form of a free-form copper wire winding, for example prefabricated on a carrier.

The total mass of the matrix 5 relative to the total mass of the coating material 8 is again 5 to 25% by mass.

The total mass of the first filler 6 and the second filler 7 relative to the total mass of the coating material 8 is 75-95% by mass, and the proportion of the first filler 6, i.e. the soft magnetic powder, relative to the total mass of the first filler 6 and the second filler 7 is higher than in the matrix from the induction component 1 from FIG. 1, in particular 75-95% by mass. The proportion of the second filler 7, i.e. in particular Al ₂ O ₃ , is therefore lower. A higher proportion of the soft magnetic powder is advantageous from the point of view of the magnetic properties of the induction component 10.

The inductive component 10 is also characterized by a high power density and high efficiency due to the use of the coating material 8. A high magnetic permeability (μ _R =2-4 or 10-500) as well as high leakage inductance and resonant inductance are also obtained. Furthermore, the coating material 8 has good thermal conductivity, which further increases the power density of the inductive component 10.

Claims (22)

An inductive component comprising a copper wire winding (3) and a coating material (8) surrounding the copper wire winding (3), the coating material (8) comprising a matrix (5) and a first filler (6) dispersed within the matrix (5);
The matrix (5) comprises at least one selected from alumina cement and phosphate cement,
The first filler (6) comprises at least one soft magnetic powder,
An induction component, wherein the total mass of the matrix (5) relative to the total mass of the coating material (8) is 5 to 25 mass %. 2. The inductive component according to claim 1, further comprising at least one second filler (7), said second filler ( ₇ ) in particular comprising _Al2O3 . The inductive component of claim 2, wherein the first filler (6) and the second filler (7) are not sintered. The induction component according to claim 2 or 3, wherein the total mass of the first and second fillers (6, 7) relative to the total mass of the coating material (8) is 75 to 95 mass %. An induction component according to any one of claims 2 to 4, in which there is no magnetic core surrounded by the copper wire winding (3), and the total mass of the first filler (6) is 75 to 95 mass % of the total mass of the first and second fillers (6, 7). 5. Inductive component according to any one of claims 2 to 4, further comprising a magnetic core (4), in particular a ferrite core, said copper wire winding (3) at least partially surrounding said magnetic core (4). The induction component according to claim 6, wherein the total mass of the first filler (6) is 1 to 50 mass% relative to the total mass of the first filler and the second filler (6, 7). The induction component according to claim 6 or 7, wherein the total mass of the second filler (7) is 50 to 99 mass% of the total mass of the first filler and the second filler (6, 7). An inductive component comprising a copper wire winding (3) and a covering material (8) surrounding the copper wire winding (3), the covering material (8) comprising a matrix (5) and a first filler (6) and at least one second filler (7) dispersed within the matrix (5);
The matrix (5) comprises at least one selected from alumina cement and phosphate cement,
The first filler (6) comprises at least one soft magnetic powder,
The second filler (7) comprises in particular Al ₂ O ₃ ,
An induction component, wherein the total mass of the first and second fillers (6, 7) relative to the total mass of the coating material (8) is 75 to 95 mass %. An inductive component comprising a copper wire winding (3) and a covering material (8) surrounding the copper wire winding (3), the covering material (8) comprising a matrix (5) and a first filler (6) and at least one second filler (7) dispersed within the matrix (5);
The matrix (5) comprises at least one selected from alumina cement and phosphate cement,
The first filler (6) comprises at least one soft magnetic powder,
The second filler (7) comprises in particular Al ₂ O ₃ ,
An induction component, wherein there is no magnetic core surrounded by the copper wire winding (3), and the total mass of the first filler (6) relative to the total mass of the first and second fillers (6, 7) is 75 to 95 mass %. An inductive component comprising a copper wire winding (3) and a covering material (8) surrounding the copper wire winding (3), the covering material (8) comprising a matrix (5), a first filler (6) dispersed within the matrix (5), at least one second filler (7), and a magnetic core (4);
The matrix (5) comprises at least one selected from alumina cement and phosphate cement,
The first filler (6) comprises at least one soft magnetic powder,
The copper wire winding (3) at least partially surrounds the magnetic core (4);
An induction component, wherein the total mass of the first filler (6) relative to the total mass of the first filler and the second filler (6, 7) is 1 to 50 mass %. An inductive component comprising a copper wire winding (3) and a covering material (8) surrounding the copper wire winding (3), the covering material (8) comprising a matrix (5), a first filler (6) dispersed within the matrix (5), at least one second filler (7), and a magnetic core (4);
The matrix (5) comprises at least one selected from alumina cement and phosphate cement,
The first filler (6) comprises at least one soft magnetic powder,
The copper wire winding (3) at least partially surrounds the magnetic core (4);
An induction component, wherein the total mass of the second filler (7) relative to the total mass of the first filler and the second filler (6, 7) is 50 to 99 mass %. Inductive component according to claim 11 or ₁₂ , wherein the second filler (7) comprises _Al2O3 . An inductive component according to any one of claims 9, 10 and 13, wherein the first filler (6) and the second filler (7) are not sintered. The inductive component according to any one of claims 11 to 14, wherein the soft magnetic powder is selected from carbonyl iron powder and ferrite powder. An induction component according to any one of claims 1 to 15, wherein the coating material (8) comprises at least one polymer, in particular a thermoplastic polymer. The inductive component according to claim 9, further comprising a magnetic core (4), in particular a ferrite core, and the copper wire winding (3) at least partially surrounds the magnetic core (4). An induction component according to any one of claims 1 to 17, wherein the component (1, 10) does not contain Portland cement. An inductive component according to any one of claims 1 to 18, configured as a transformer. Mixing a matrix material with a first filler (6), water, and optionally at least one flow agent while generating a slurry, said matrix material comprising at least one selected from non-hardening alumina cement and non-hardening phosphate cement, said first filler (6) comprising at least one soft magnetic powder;
Surrounding the copper wire winding (3) with said slurry;
and at least partially curing the matrix material with water at a temperature in the range of 50-150°C to form a coating (8).
A method for producing an inductive component (1, 10), wherein the total mass of the matrix material (5) relative to the total mass of the coating material (8) is 5 to 25% by mass. The method of claim 20, further comprising the step of annealing the matrix material after the hardening, the annealing being performed at a temperature in the range of 100 to 150°C. The method according to claim 20 or 21, comprising the step of surrounding a magnetic core (4), in particular a ferrite core, with the copper wire winding (3).

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