EP3772070A1 - Inductive component and method for manufacturing an inductive component - Google Patents

Abstract

In a method for producing an inductive component (1), a base body, which comprises a magnetic material, is sintered and then comminuted. The crushing results in sintered particles (P ₁, P ₂), which are bonded with a binding agent (B ₁, B <sub> 2 </ sub>) can be mixed to at least one mixture. The at least one mixture and at least one coil (2) are arranged in a mold and then the binder (B ₁, B ₂) is activated so that the sintered particles (P ₁, P ₂) with the binder (B ₁, B ₂) at least one magnetic core (3, 4) which at least partially surrounds the at least one coil (2). The method enables simple and inexpensive production of the inductive component (1) with improved electromagnetic properties.

Description

The present patent application takes priority over the German patent application DE 10 2019 211 439.3 claim, the contents of which are incorporated herein by reference.

The invention relates to a method for producing an inductive component and an inductive component.

From the EP 2 211 360 A2 a method for producing an inductive component is known. A solid body is successively formed from a coil and several magnetic powders. The body is then placed in a furnace and sintered at approx. 900 ° C. to form the inductive component.

The invention is based on the object of creating a method that enables simple and inexpensive production of an inductive component with improved electromagnetic properties.

This object is achieved by a method with the features of claim 1. First, a base body is provided which comprises a magnetic material. The magnetic material can be generated, for example, by recycling magnetic waste material or by recycling raw material. For example, magnetic waste material can be crushed, filtered and / or mixed and activated into the magnetic material. The base body is formed in particular from the magnetic material. The sintering of the base body can be done in a simple and inexpensive manner at a comparatively high temperature, since the sintering without the at least one coil takes place and the melting temperature of the material of the at least one coil does not have to be taken into account. After sintering, the sintered base body is comminuted, so that sintered particles are produced. By comminuting and / or selecting the sintered particles for generating the at least one mixture, the electromagnetic properties of the inductive component can be influenced. At least one mixture is then produced from the sintered particles and a binder. The at least one mixture is arranged together with the at least one coil in a mold and then the binder is activated, so that the binder connects the sintered particles to form at least one magnetic core. The formed magnetic core surrounds the at least one coil in the desired manner. The at least one magnetic core preferably completely surrounds the at least one coil with the exception of connection contacts. Because the sintering takes place without the at least one coil and the sintered particles are connected to the at least one magnetic core by means of the binder, the production of the inductive component is simple and inexpensive. By comminuting the sintered base body and selecting the sintered particles used to generate the at least one mixture, the electromagnetic properties of the inductive component can be influenced in a targeted manner.

A method according to claim 2 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The at least one ferrite material is available simply and inexpensively. The at least one ferrite material enables high inductance and / or soft saturation. The at least one ferrite material enables comparatively lower AC voltage losses (AC Losses) and / or comparatively higher voltages in high voltage tests (AC HiPot test). The at least one ferrite material comprises in particular manganese (Mn), zinc (Zn) and / or nickel (Ni), for example NiZn and / or MnZn.

A method according to claim 3 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. Because the sintering takes place without the at least one coil, sintering is possible at a comparatively high temperature Ts. The duration of the sintering process is shorter, the higher the temperature Ts is. The duration of the sintering process can be shortened accordingly. Sintering affects the electromagnetic properties of the sintered particles. Because the temperature T _S and the duration of the sintering can be selected or set easily and flexibly, the electromagnetic properties can be influenced in the desired manner.

A method according to claim 4 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The aspect ratio characterizes the ratio of a minimum dimension A _min to a maximum dimension A _{max of} the respective sintered particle. The following applies to the aspect ratio A: A = A _min / A _max . Before the at least one mixture is produced, the sintered particles are processed in such a way that their shape approaches a spherical shape and / or a cube shape. The aspect ratios of the sintered particles are at least partially reduced by machining. Because the sintered particles approximate their shape to a spherical shape or a cube shape, the at least one magnetic core has an essentially uniform density and thus essentially uniform electromagnetic properties. In addition, the at least one magnetic core has high mechanical stability, since the sintered particles are evenly wetted by the binder.

A method according to claim 5 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. Because the sintered particles are processed by means of a ball mill, their shape approaches a spherical shape and / or a cube shape. As a result of the processing, the aspect ratios of the sintered particles are preferably at least partially reduced. The ball mill comprises a rotating drum in which balls, for example metal balls, are located. The sintered particles are fed to the ball mill as ground material and processed by the balls in the drum in the manner described.

A method according to claim 6 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. Because the sintered particles are separated on the basis of the particle shape and / or the particle size, the sintered particles used for the at least one mixture can be selected as desired. The separation or selection based on the particle shape takes place, for example, in such a way that sintered particles with an aspect ratio A of at least 0.5, in particular at least 0.6, in particular at least 0.7, in particular at least 0.8, and in particular at least 0.9 are separated and used for generating the at least one mixture. Furthermore, the sintered particles are separated on the basis of the particle size, for example, in such a way that a first coarse fraction and a second fine fraction of sintered particles be generated. Furthermore, the sintered particles are separated on the basis of the particle size, for example, in such a way that the particle size is in a desired range. By selecting the sintered particles according to their particle shape and / or particle size, the electromagnetic properties of the at least one core can be influenced in a targeted manner.

A method according to claim 7 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. Preferably at least 80%, in particular at least 90%, and in particular at least 95% of the sintered particles used to produce the at least one mixture have the respective aspect ratio A. The aspect ratio A ensures that the sintered particles come as close as possible in their shape to a spherical or cube shape . The aspect ratio A characterizes the ratio of a minimum dimension A _min to a maximum dimension A _{max of} the respective sintered particle. The following applies to the aspect ratio A: A = A _min / A _max . For the aspect ratio A: 0.5 A 1, in particular 0.6 A 0.9, and in particular 0.7 A 0.8. The aspect ratio A can be selected depending on the desired distribution of the magnetic flux. Advantageous properties result from an aspect ratio A ≈ 0.75.

A method according to claim 8 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. Preferably at least 80%, in particular at least 90%, and in particular at least 95% of the sintered particles used have the respective minimum dimension A _min . The sintered particles used are preferably selected according to their particle size separated into a first fraction with first sintered particles and into a second fraction with second sintered particles. For a minimum dimension A _{1min of} the first sintered particles, the following applies preferably: 500 μm A _1min 1000 μm, in particular 600 μm A _1min 900 μm, and in particular 700 μm A _1min 800 μm. For a minimum dimension A _{2min of} the second sintered particles, the following preferably applies: 10 μm A _2min 500 μm, in particular 100 μm A _2min 400 μm, and in particular 200 μm A _2min 300 μm. Preferably at least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the sintered particles used have the minimum dimension A _1min or A _2min .

A method according to claim 9 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The first sintered particles and the second sintered particles preferably differ in their particle shape and / or in their particle size. The sintered particles are preferably separated according to their aspect ratio and / or their particle size, in particular their minimum dimension and / or their maximum dimension. Through the targeted selection of the sintered particles used, the electromagnetic properties of the inductive component can be influenced in the desired manner.

The sintered particles are preferably separated into a first coarse fraction with first sintered particles and into a second fine fraction with second sintered particles which are smaller than the first sintered particles. By separating the sintered particles into a first coarse fraction and a second fine fraction, a first mixture for forming a first magnetic core and a second mixture can be generated to form a second magnetic core. To produce the first mixture, the first sintered particles are mixed with a binder. Accordingly, the second sintered particles are mixed with a binder to produce the second mixture. The at least one coil and the first mixture are arranged in a mold and then the binding agent of the first mixture is activated, so that the first sintered particles with the binding agent form the first magnetic core. The component obtained with the at least one coil and the first magnetic core is arranged together with the second mixture in a second mold. The binder is then activated in the second mixture, so that the second sintered particles form a second magnetic core with the binder. The second magnetic core at least partially surrounds the first magnetic core and the at least one coil.

For a minimum dimension A _{1min of} the first sintered particles, the following applies preferably: 500 μm A _1min 1000 μm, in particular 600 μm A _1min 900 μm, and in particular 700 μm A _1min 800 μm. For a minimum dimension A _{2min of} the second sintered particles, the following preferably applies: 10 μm A _2min 500 μm, in particular 100 μm A _2min 400 μm, and in particular 200 μm A _2min 300 μm. Preferably at least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the sintered particles used have the minimum dimension A _1min or A _2min .

The two-stage manufacturing process optimizes the electromagnetic and mechanical properties of the inductive component. By dividing the sintered particles into several fractions and the selection and distribution of the sintered particles can influence the electromagnetic properties in the desired manner. The first magnetic core preferably completely surrounds the at least one coil with the exception of connection contacts. With the exception of terminal contacts, the second magnetic core preferably completely surrounds the first magnetic core and the at least one coil. By generating several magnetic cores with differing sintered particles, the electromagnetic and / or mechanical properties of the component can be influenced in the desired manner. Because the comparatively smaller second sintered particles form the outer second magnetic core, the component has in particular a smooth surface.

A method according to claim 10 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The sintered particles are preferably separated into first sintered particles and second sintered particles according to their particle shape and / or their particle size. The sintered particles are preferably separated according to their particle size, in particular their minimum dimension and / or their maximum dimension, into a first coarse fraction with the first sintered particles and a second fine fraction with second sintered particles that are smaller than the first sintered particles. A first mixture is produced from the first sintered particles and a binder. Correspondingly, a second mixture is produced from the second sintered particles and a binder. The at least one coil and the first mixture are arranged in a first mold and then the binding agent in the first mixture is activated, so that the first sintered particles with the binding agent form the first magnetic core. The first magnetisehe The core at least partially surrounds the at least one coil. The resulting component with the at least one coil and the first magnetic core and the second mixture are arranged in a second mold and then the binder in the second mixture is activated so that the second sintered particles with the binder form the second magnetic core. The second magnetic core at least partially surrounds the first magnetic core and the at least one coil. The first magnetic core preferably completely surrounds the at least one coil with the exception of connection contacts. With the exception of terminal contacts, the second magnetic core preferably completely surrounds the first magnetic core and the at least one coil. By generating several magnetic cores with differing sintered particles, the electromagnetic and / or mechanical properties of the component can be influenced in the desired manner.

A method according to claim 11 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The binder is activated in a simple manner by increasing the temperature of the at least one mixture and / or by increasing the pressure on the at least one mixture. By activating the binder, the sintered particles are connected to one another to form the at least one core. A polymer material and / or a resin, for example, is used as the binder.

A method according to claim 12 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The density and / or the air gap of the inductive component is set in the desired manner by the mass ratio m. The mass ratio m describes the ratio of the mass mp of the sintered particles to the mass m _{B of} the binder. The following applies to the mass ratio m: m = m _P / m _B. With a higher mass fraction of the sintered particles in relation to the binder, the density increases and / or the air gap of the inductive component decreases and vice versa. The density and / or the air gap influence the saturation behavior of the inductive component.

A method according to claim 13 ensures simple and inexpensive production of the inductive component with improved electromagnetic properties. The base body is produced in a simple manner by pressing the magnetic material. The magnetic material is preferably in the form of granules and / or powder. The magnetic material includes at least one ferrite material. The magnetic material is preferably provided in such a way that at least one raw material and / or at least one waste material is processed and / or activated. Preferably, several raw materials and / or several waste materials are mixed and / or processed. Preferably, magnetic waste materials are recycled.

The invention is also based on the object of creating an inductive component that can be produced simply, inexpensively and with improved electromagnetic properties.

This object is achieved by an inductive component with the features of claim 14. The advantages of the inductive component correspond to the advantages of the method already described. The inductive component can in particular also be developed with the features of at least one of claims 1 to 13. The sintered particles are with the activated binder connected to the at least one core. The sintered particles comprise a magnetic material, in particular at least one ferrite material. The sintered particles have a respective particle shape, in particular a respective aspect ratio, and / or a respective particle size, as has already been described for claims 1 to 13. Reference is made to the corresponding features.

An inductive component according to claim 15 ensures simple and inexpensive manufacture with improved electromagnetic properties. The electromagnetic properties can be influenced in the desired manner through the formation of several magnetic cores and the selection of the sintered particles used for this purpose.

Fig. 1

eine Schnittdarstellung eines induktiven Bauteils,

Fig. 2A und 2B

ein Ablaufdiagramm mit den Schritten zur Herstellung des induktiven Bauteils gemäß Fig. 1,

Fig. 3

Diagramme des Gütefaktors Q in Abhängigkeit der Zeit t und der Frequenz f, wobei das obere Diagramm ein induktives Bauteil umfassend eine Eisenlegierung nach dem Stand der Technik, das mittlere Diagramm ein erfindungsgemäßes induktives Bauteil mit Ferritmaterial umfassend Mangan und Zink und das untere Diagramm ein erfindungsgemäßes induktives Bauteil mit Ferritmaterial umfassend Nickel und Zink veranschaulicht,

Fig. 4

Diagramme der Wechselspannungsverlustleistung P_AC in Abhängigkeit der Zeit t und der Frequenz f, wobei das obere Diagramm ein induktives Bauteil umfassend eine Eisenlegierung nach dem Stand der Technik, das mittlere Diagramm ein erfindungsgemäßes induktives Bauteil mit Ferritmaterial umfassend Mangan und Zink und das untere Diagramm ein erfindungsgemäßes induktives Bauteil mit Ferritmaterial umfassend Nickel und Zink veranschaulicht,

Fig. 5

ein Diagramm des Gütefaktors Q in Abhängigkeit der Frequenz f und der Zeit t für ein induktives Bauteil umfassend eine Eisenlegierung nach dem Stand der Technik, und

Fig. 6

ein Diagramm des Gütefaktors Q in Abhängigkeit der Frequenz f und der Zeit t für ein erfindungsgemäßes induktives Bauteil mit Ferritmaterial umfassend Mangan und Zink.

Further features, advantages and details of the invention emerge from the following description of an exemplary embodiment. Show it:

Fig. 1

a sectional view of an inductive component,

Figures 2A and 2B

a flow chart with the steps for producing the inductive component according to FIG Fig. 1 ,

Fig. 3

Diagrams of the quality factor Q as a function of time t and frequency f, with the upper diagram an inductive component comprising an iron alloy according to the prior art, the middle diagram an inductive component according to the invention with ferrite material comprising manganese and zinc and the lower diagram an inventive inductive component with ferrite material comprising nickel and zinc illustrates,

Fig. 4

Diagrams of AC power loss P _AC as a function of time t and frequency f, with the upper diagram an inductive component comprising an iron alloy according to the prior art, the middle diagram an inductive component according to the invention with ferrite material comprising manganese and zinc and the lower diagram an inventive component illustrates inductive component with ferrite material comprising nickel and zinc,

Fig. 5

a diagram of the quality factor Q as a function of the frequency f and the time t for an inductive component comprising an iron alloy according to the prior art, and

Fig. 6

a diagram of the quality factor Q as a function of the frequency f and the time t for an inductive component according to the invention with ferrite material comprising manganese and zinc.

An inductive component 1 comprises a coil 2, a first magnetic core 3 and a second magnetic core 4. The coil 2 is designed, for example, as a cylinder coil. The coil 2 consists of an electrically conductive material. The coil 2 has connection contacts 5, 6.

The first magnetic core 3 surrounds the coil 2. The first magnetic core 3 comprises first sintered particles P ₁ , which are bonded to one another by means of a first binding agent B ₁ . The second magnetic core 4 surrounds the first magnetic core 3 and the coil 2. The second magnetic core 4 comprises second sintered particles P ₂ , which are bonded to one another by means of a second binding agent B ₂ . The connection contacts 5, 6 are led to the outside through the first magnetic core 3 and the second magnetic core 4.

The first sintered particles P ₁ each have a minimum dimension A _1min and a maximum dimension A _1max . The first sintered particles P ₁ have a respective first aspect ratio A ₁ , where:
A ₁ = A _1min / A _1max . At least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the first sintered particles P ₁ have a respective minimum dimension A _1min , where: 500 μm A _1min 1000 μm, in particular 600 μm A _1min 900 µm, and in particular 700 µm A _1min 800 µm. At least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the first sintered particles P ₁ have a respective aspect ratio A ₁ , where: 0.5 A ₁ 1, in particular 0.6 A ₁ 1, in particular 0.7 A ₁ 1, in particular 0.8 A ₁ 1, and in particular 0.9 A ₁ 1. Preferably, the aspect ratio A ₁ : 0.5 A ₁ applies 1, in particular 0.6 A ₁ 0.9, and in particular 0.7 A ₁ 0.8. The aspect ratio A ₁ can be selected as a function of the desired distribution of the magnetic flux. Advantageous properties result from an aspect ratio A ₁ ≈ 0.75.

The second sintered particles P ₂ each have a minimum dimension A _2min and a maximum dimension A _2max . The second sintered Particles P ₂ have a respective second aspect ratio A ₂ , where: A ₂ = A _2min / A _2max . At least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the second sintered particles P ₂ have a respective minimum dimension A _2min , where: 10 μm A _2min 500 μm, in particular 100 μm A _2min 400 µm, and in particular 200 µm A _2min 300 µm. At least 70%, in particular at least 80%, in particular at least 90%, and in particular at least 95% of the second sintered particles P ₂ have a respective aspect ratio A ₂ , where: 0.5 A ₂ 1, in particular 0.6 A ₂ 1, in particular 0.7 A ₂ 1, in particular 0.8 A ₂ 1, and in particular 0.9 A ₂ 1. Preferably, the aspect ratio A ₂ : 0.5 A ₂ applies 1, in particular 0.6 A ₂ <0.9, and in particular 0.7 A ₂ <0.8. The aspect ratio A ₂ can be selected depending on the desired distribution of the magnetic flux. Advantageous properties result from an aspect ratio A ₂ ≈ 0.75.

The first sintered particles P ₁ and the second sintered particles P ₂ differ in their particle shape or in their aspect ratio A ₁ or A ₂ and / or in their particle size or in their minimum dimension A _1min or A _2min .

The following is the method for producing the inductive component 1 on the basis of FIG Fig. 2 described:
In a step S ₁ , starting materials R ₁ to R _n are first mixed with one another to form a starting material mixture R _M. The starting materials R ₁ to R _n are, for example, raw materials and / or waste materials that are to be recycled or reprocessed. The Starting materials R ₁ to R _n include, for example, zinc oxide (ZnO), manganese oxide (MnO) and / or iron oxide.

The starting material mixture R _M is activated and / or calcined in a step S ₂ . During calcination, a starting material mixture R _M containing calcium and magnesium carbonate is heated for dehydration and / or for decomposition.

The activated raw material mixture R _M forms a magnetic material M. The magnetic material M is, for example, powdery and / or granular. The magnetic material M comprises at least one ferrite material, for example MnZn ferrite material and / or NiZn ferrite material.

The magnetic material M is pressed into a base body G in a step S ₃ . The base body G is also referred to as a green body.

In a subsequent step S ₄ , the base body G is sintered. The sintering takes place at a temperature Ts, where: Ts 1000 ° C, in particular Ts 1100 ° C, in particular Ts 1200 ° C. The sintered base body is denoted by Gs.

In a step S ₅ , the sintered base body Gs is comminuted. The crushing takes place, for example, by means of a crusher or crushing machine (crusher). The crushing produces sintered particles, which are generally referred to as P. The sintered particles P each have a minimum dimension A _min and a maximum dimension A _max , which define a respective aspect ratio A. The following applies to the respective aspect ratio: A = A _min / A _max . After shredding the With the sintered base body Gs, the aspect ratios A of the sintered particles P are widely scattered. In particular, sintered particles P with an elongated shape, which each have a small aspect ratio A, are also produced during comminution. For the further processing of the sintered particles P, a shape is desired which essentially corresponds to a spherical shape and / or a cube shape.

In a step S ₆ , the aspect ratios A of the sintered particles P are reduced. This means that the maximum dimension A _{max of} the respective sintered particle P is matched to the minimum dimension A _min . For this purpose, the sintered particles P are processed, for example, by means of a ball mill. The ball mill comprises a drum and metal balls arranged therein. The sintered particles P are placed in the drum and, due to a rotation of the drum, are processed by further comminution and / or friction by means of the metal balls, so that the aspect ratios A of the sintered particles P are at least partially reduced.

In a step S ₇ , the sintered particles P are separated on the basis of their particle shape and / or on the basis of their particle size. The sintered particles P are separated into a first fraction with first sintered particles P ₁ and a second fraction with second sintered particles P ₂ . The first sintered particles P ₁ have the minimum dimension A _1min and the maximum dimension A _1max and the aspect ratio A ₁ , whereas the second sintered particles P _{2 have} the minimum dimension A _2min , the maximum dimension A _2max and the aspect ratio A ₂ . The first fraction comprises coarser particles compared to the second fraction. Accordingly, for at least 70% of the sintered particles P ₁ , P ₂ : A _1min > A _2min and / or A _1max > A _2min and / or A _1min ≥ A _2max .

Sintered particles P sorted out in step S ₇ which do not belong to either the first fraction or the second fraction can be returned and further comminuted in step S ₅ and / or processed further in step S ₆ . This is in Fig. 2 illustrated by the dashed lines.

In a subsequent step S ₈₁ , a first mixture X _{1 is} produced from the first sintered particles P ₁ and the first binder B ₁ . Correspondingly, in a step S _82, a second mixture X _{2 is} produced from the second sintered particles P ₂ and the second binding agent B ₂ . The binders B ₁ and B ₂ can be the same or different. The binders B ₁ , B ₂ are, for example, a polymer plastic and / or a resin.

The first mixture X ₁ has a mass ratio m _{1 of} the mass m _{P1 of} the first sintered particles P ₁ to the mass m _{B1 of} the first binder B ₁ . For the mass ratio m ₁ , m ₁ = m _P1 / m _B1 therefore applies. The following preferably applies to the mass ratio m ₁ : 75/25 m ₁ 99/1, in particular 80/20 m ₁ 98/2, and 85/15 m ₁ 95/5. The second mixture X ₂ has a mass ratio m _{2 of} the mass m _{P2 of} the second sintered particles P ₂ to the mass m _{B2 of} the second binder B ₂ . For the mass ratio m ₂ , m ₂ = mp ₂ / m _B2 therefore applies. The following preferably applies to the mass ratio m ₂ : 75/25 m ₂ 99/1, in particular 80/20 m ₂ 98/2, and 85/15 m ₂ 95/5. The mass ratio is generally referred to as m.

In a step S ₉ , the first mixture X ₁ and the coil 2 are arranged in a first form F ₁ . The first binder B _{1 is then} activated, so that the first binder B ₁ connects the first sintered particles P ₁ to form the first magnetic core 3. To activate the first Binder B ₁ , a pressure p _{1 is increased} to the first mixture X ₁ and / or a temperature T _{1 of} the first mixture X ₁ . After the first binding agent B ₁ has cured, the first magnetic core 3 with the coil 2 is removed from the mold.

In a subsequent step S ₁₀ , the first magnetic core 3 with the coil 2 and the second mixture X _{2 are arranged} in a second mold F ₂ . The second binder B _{2 is then} activated, so that the second binder B ₂ connects the second sintered particles P ₂ to form the second magnetic core 4. The second binder B ₂ is activated by increasing a pressure p ₂ on the second mixture X ₂ and / or by increasing a temperature T _{2 of} the second mixture X ₂ . After the second binding agent B ₂ has cured, the second core 4 with the first magnetic core 3 and the coil 2 is removed from the mold.

As a result of the demolding, the inductive component 1 is provided in a step S ₁₁ .

Fig. 3 illustrates measurement curves for the quality factor Q (Q-Value) at frequencies f of 100 kHz, 500 kHz and 1 MHz over time t. The quality factor Q of the inductive components 1 according to the invention (cf. middle and lower diagram) is more constant over time t compared to the inductive component according to the prior art (cf. upper diagram). In addition to the measurement curves, in Fig. 3 Smoothed measurement curves are illustrated, which should enable a simpler comparison with regard to the constancy of the quality factors Q.

Illustrated in a corresponding manner Fig. 4 Measurement curves for the alternating voltage power loss P _AC at frequencies f of 400 kHz and 1.2 MHz over time t. The AC power loss P _{AC of} the inductive components 1 according to the invention (cf. middle and lower diagram) is more constant over time t in comparison to the inductive component according to the prior art (cf. upper diagram). In addition to the measurement curves, in Fig. 4 Smoothed measurement curves are illustrated, which are intended to enable a simpler comparison with regard to the constancy of the alternating voltage power loss P _AC .

The components 1 according to the invention hardly age thermally and thus ensure that the behavior of an electrical circuit with the inductive components 1 according to the invention does not change and their function does not change due to parameters that change over time t, such as the quality factor Q or the AC power loss P _AC is impaired. A comparison of the measurement curves in Fig. 5 with the measurement curves in Fig. 6 shows that the quality factor Q of the inductive component 1 according to the invention hardly changes over time t and the components 1 according to the invention hardly age thermally.

In general:
The inductive component 1 has at least one coil 2. The inductive component 1 preferably has exactly one coil or exactly two coils.

The sintered particles P produced by comminuting the sintered base body Gs can be processed, separated and / or selected in any desired manner. The order of the steps mentioned is arbitrary. Known filters and / or sieves and / or separators can be used for separating and / or selecting. By processing, separating and / or selecting the sintered particles P can the electromagnetic properties of the inductive component 1 can be set in the desired manner. In particular, the inductance, the saturation behavior and / or the air gap can be adjusted.

The activation of the binding agent B can take place by cold pressing or hot pressing.

The magnetic material M and thus the at least one magnetic core 3, 4 preferably comprises at least one ferrite material. Ferrite material is inexpensive and readily available. By using ferrite material, comparatively good electromagnetic properties of the inductive component 1 are achieved. In particular, the inductive component 1 has a high inductance, a desired saturation behavior, low losses and / or can be operated with a high voltage. Such inductive components 1 pass, for example, a high voltage test (AC HiPot test) at a voltage of 3 kV _AC (3 mA, 3 sec).

The sintered particles are generally referred to as P. The aspect ratio is generally referred to as A. The minimum dimension is generally referred to as A _min . The maximum dimension is generally referred to as A _max .

Claims (15)

Method for manufacturing an inductive component with the steps: - Providing a base body (G) comprising a magnetic material (M), - sintering the base body (G), - Crushing the sintered base body (Gs) into sintered particles (P, P ₁ , P ₂ ), - Generating at least one mixture (X _1, X ₂ ) from the sintered particles (P ₁ , P ₂ ) and a binder (B ₁ , B ₂ ), - Arranging the at least one mixture (X _1, X ₂ ) and at least one coil (2) in a mold (F ₁ , F ₂ ), and - Activation of the binding agent (B ₁ , B ₂ ) in the at least one mixture (X _1, X ₂ ), so that the sintered particles (P ₁ , P ₂ ) with the binding agent (B ₁ , B ₂ ) have at least one magnetic core (3, 4) which at least partially surrounds the at least one coil (2). Method according to claim 1, characterized in that
that the magnetic material (M) comprises at least one ferrite material. Method according to claim 1 or 2, characterized in that
that the sintering takes place at a temperature Ts, where: Ts 1000 ° C, in particular T _S 1100 ° C, in particular T _S 1200 ° C. Method according to at least one of the preceding claims, characterized in that
that the sintered particles (P, P ₁ , P ₂ ) have a respective aspect ratio (A) and the aspect ratios (A) are at least partially reduced before the at least one mixture (X _1, X ₂ ) is produced. Method according to at least one of the preceding claims, characterized in that
that the sintered particles (P, P ₁ , P ₂ ) are processed by means of a ball mill before the at least one mixture (X _1, X ₂ ) is produced. Method according to at least one of the preceding claims, characterized in that
that the sintered particles (P, P ₁ , P ₂ ) are separated on the basis of the particle shape and / or the particle size before the at least one mixture (X _1, X ₂ ) is produced. Method according to at least one of the preceding claims, characterized in that
that at least 70% of generating the at least one mixture (X _1, X ₂₎ sintered particles used (P, P _1, P ₂₎ a respective aspect ratio A have, for which applies: 0.5 ≤ A ≤ 1, in particular 0 , 6 A 1, in particular 0.7 A 1, in particular 0.8 A 1, and in particular 0.9 A 1. Method according to at least one of the preceding claims, characterized in that
that at least 70% of the sintered particles (P, P ₁ , P ₂ ) used to produce the at least one mixture (X _1, X ₂ ) have a respective have a minimum dimension A _min , for which the following applies: 10 µm ≤ A _min ≤ 1000 µm. Method according to at least one of the preceding claims, characterized in that
that the sintered particles (P, P ₁ , P ₂ ) before the at least one mixture (X _1, X ₂ ) is produced in a first fraction with first sintered particles (P ₁ ) and in a second fraction with the first sintered ones Particles (P ₁ ) differentiating second sintered particles (P ₂ ) are separated. Method according to at least one of the preceding claims, characterized in that
that a first magnetic core (3) is produced with first sintered particles (P ₁ ), and
that with the second sintered particles (P ₂ ) differing from the first sintered particles (P ₁ ) a second magnetic core (4) is produced. Method according to at least one of the preceding claims, characterized in that
that the binder (B _1, B ₂₎ by increasing a temperature (T _1, T ₂₎ and / or by increasing a pressure (p _1, p ₂₎ is activated. Method according to at least one of the preceding claims, characterized in that
that the at least one mixture (X _1, X ₂ ) is generated in such a way that for a mass ratio m of the sintered particles (P ₁ , P ₂ ) to the Binding agent (B ₁ , B ₂ ) applies: 75/25 m 99/1, in particular 80/20 m 98/2, and in particular 85/15 m 95/5. Method according to at least one of the preceding claims, characterized in that
that the base body (G) is provided by pressing the magnetic material (M). Comprehensive inductive component - at least one coil (2), - At least one magnetic core (3, 4) which at least partially surrounds the at least one coil (2), characterized,
that the at least one core (3, 4) is formed by means of sintered particles (P ₁ , P ₂ ) and a binding agent (B ₁ , B ₂ ). Inductive component according to claim 14, characterized in that a first magnetic core (3) with first sintered particles (P ₁ ) at least partially surrounds the at least one coil (2), and that a second magnetic core (4) with it from the first sintered particles (P ₁ ) differentiating second sintered particles (P ₂ ) the first magnetic core (3) and the at least one coil (2) at least partially surrounds.

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