DE102022134934A1 - Inductive component, mold tool and embedding method - Google Patents

Abstract

An easily manufactured inductive component with precisely adjustable electrical and magnetic properties is specified. The inductive component has a body with a central region of an electrical conductor. The central region is centered in the body. The body also has one or more recesses that open outwards.

Description

The invention relates to inductive components, especially inductive components with improved magnetic properties, mold tools for producing such components and methods for embedding, e.g. for embedding electrical conductors in a component body.

Inductive components can be used in electrical circuits where they implement inductive circuit elements. The inductances of such components are generally characterized by the shape of an electrical conductor and the magnetic properties of its surroundings. For example, a coil can be encapsulated in a surrounding material. The position of the coil in the encapsulation material influences the magnetic and electrical properties of the corresponding component.

For example, from the printed publications US9,728,331 B2 , US 4,801,912 A or US 2010/0219924 A1 Inductive elements with a holder for the coil are known. From the US 2012/0019343 A1 or US 2009/0250836 A1 Complex process steps for the production of inductive components are known.

However, there is still a desire for inductive components that can be produced using simple, easy-to-perform manufacturing steps and that have precisely adjustable magnetic properties. An inductive component is also desirable in which contact connections for connection to an external circuit environment are precisely located and aligned.

For this purpose, an inductive component or a mold tool and a method for embedding an electrical conductor are specified according to the independent claims. Dependent claims specify advantageous embodiments.

The inductive component comprises an electrical conductor. The electrical conductor has a first connection and a second connection. The electrical conductor also has a central region. The central region is arranged electrically between the first connection and the second connection. The inductive component also has a body in which the central region is arranged. The central region is centered in the body. The body also has a first recess that is open to the outside.

The electrical arrangement of the central region between the first terminal and the second terminal essentially means that the electrical conductor is designed such that the central region of the electrical conductor is connected in series between the first terminal and the second terminal. The centering of the central region in the body means that the procession of the central region in the body is determined with high precision. As a result, the magnetic environment of the central region of the electrical conductor is essentially determined with high precision, so that the electrical and magnetic properties of the inductive element can be adjusted with high precision.

The presence of the recess that opens outwards is directly related to the high precision adjustable inductance. The recess that opens outwards serves to hold the electrical conductor and in particular its central area in the intended position during the manufacturing process of the inductive component. Mold materials can then be used to surround the central area, whereby a secure fixation of the central area is guaranteed even at high mold pressures. The position within the body and thus the thicknesses of the material of the body in the various directions around the central area are thus firmly defined, which results in the high precision of the adjustability of the electrical magnetic properties of the inductive component.

The central area of the electrical conductor is essentially the area of the conductor that largely determines the electrical or magnetic properties of the inductive component.

It is possible for one or more recesses to enclose an angle β with 0° ≤ β ≤ 20° with the respective side surface. The respective side surface is the side surface that contains the respective recess. The presence of an angle > 0° means that the recess, specifically its side surface, is slanted to the side. This makes it possible - particularly when two recesses are arranged opposite each other - to fix the central area and even press it downwards so that one side of a connection is optimally aligned for later soldering and the central area is aligned relative to the material of the body. An associated mold tool can have a V-shaped area with the opening of the area pointing downwards. This means that the opening of the "V" points downwards.

It is possible that the electrical conductor in the central area is formed into one or more coils. The electrical conductor can consist of one or more wires or a Wire whose corresponding section is formed into turns that form the coil(s) of the inductive component.

The first connection and the second connection of the electrical conductor represent connection options of the inductive component, with which the inductive component can be connected to an external circuit environment. The first connection and the second connection can protrude from the body of the component on different sides of the inductive component. However, it is also possible for both connections to protrude on the same side of the body. This is particularly advantageous if the inductive component is to be connected to a circuit board using SMD technology (SMD = surface mounted device).

The coil can have essentially circular turns. The coil can in particular be a cylindrical coil or a planar coil. However, it is also possible for the turns of the coil to follow an oval cross-section or a rectangular cross-section.

It is possible that the body of the inductive component in which the central region is located contains a mold material or consists of a mold material.

Furthermore, it is possible that the central region of the electrical conductor is embedded in the body of the inductive component.

Embedding by means of molding (casting) is a simple way of producing an inductive component. It is possible for the central area and the mold material surrounding the central area to form a monolithically formed inductive component. The central area of the electrical conductor is essentially in direct contact with the mold material over its entire length.

It is possible for the body to contain a second recess which is open towards the outside and which is arranged opposite the first recess on the body such that the central region is arranged between the first and the second recess.

The importance of the recesses is that during production the associated mold tool has correspondingly shaped elements, e.g. ribs or lamellae, which hold the central area of the inductive component in its position during casting. Ribs of the mold tool can press against the central area of the electrical conductor from different directions, e.g. from opposite directions, and thus hold it in a fixed position with high precision, even if during molding, i.e. during casting with the casting compound, a high mold pressure is required for casting, depending on the mold material.

In particular, the mold tool has a cavity which is intended to be filled by the mold mass, whereby the filling of the cavity by the mold material forms the subsequent body in which the electrical conductor is monolithically enclosed with its central region.

The limitation of the cavity of the mold tool on the one hand and the positioning of the central region defined with high precision on the other hand results in an inductive component whose external dimensions can be precisely adjusted and whose central region of the electrical conductor is determined with high precision so that the magnetic environment of the electrical conductor and in particular of the central region is determined with high precision.

This allows the electrical and magnetic properties of the inductive component to be adjusted with high precision, so that an inductive component with precise electrical and magnetic properties is obtained and the inductive component can be manufactured by simple process steps.

It is possible that the inductive component further has further first recesses in the body.

The number of recesses in the body, i.e. the possible locations or directions from which the central area of the electrical conductor can be fixed during encapsulation, determines the precision with which the central area can be adjusted and the mechanical resistance that the central area can offer when the encapsulation compound is encapsulated.

However, the recesses in which the corresponding conductor section of the electrical conductor contains less mold material in its environment can be seen as inhomogeneities in the magnetic environment of the inductive component. Therefore, in general, a certain number of recesses and certain positions for the recesses result for a certain inductive component, so that the advantageous properties of the recesses outweigh the lack of the corresponding material.

The depths and widths of the recesses are ideally selected so that the necessary mechanical stability when positioning the central area is sufficiently large and the disturbance of the magnetic environment is sufficiently small.

Accordingly, it is also possible for the inductive component to comprise further second recesses in the body. First recesses and second recesses are arranged essentially on opposite sides of the inductive component.

By arranging the recesses opposite each other or the corresponding ribs opposite each other in the mold tool, the central area can be optimally clamped during production, so that the central area is optimally fixed during the application of the mold material.

In one embodiment, one or more or all recesses in the vertical direction y have a height h with 0.8*H ≤ h, where H is the height of the body. The height H of the body can be between 1 mm and 10 mm.

In one embodiment, one or more or all recesses have a width b of 0.1*L ≤ b ≤ 0.9*L, where L is the length of the body.

In one embodiment, one or more or all recesses have a depth t with 0.01*L ≤ t ≤ 0.5*L, where L is the length of the body.

It is possible that the recesses have a width b of 0.1 mm ≤ b ≤ 3.0 mm.

Accordingly, it is possible that the recesses have a depth t of 0.05 mm ≤ t ≤ 1.0 mm.

It is possible for the body of the inductive component to have a substantially cuboid shape. The substantially cuboid body can have edge lengths K1, K2, K3 that are 0.2 mm or more and 10 mm or less.

The body can have a shape that corresponds exactly to a cuboid, except for the connections. However, it is often advantageous if the exact shape of the body deviates slightly from a cuboid. For example, the edges of the cuboid can each have a bevel. Furthermore, the body can have a side surface that is designed asymmetrically to other side surfaces of the body in order to make it easier to orient the component, e.g. when connecting it to a circuit board.

It is possible that the body on the top has two oblique bevels - extending in the longitudinal direction - on the transverse sides of the top.

It is possible that the body has one or two faces, each with six edges.

It is possible that the body has two side surfaces that are opposite each other in the transverse direction x and that enclose an angle α with 0° < α ≤ 20°.

It is possible that the first port and the second port provide a flat surface accessible from the outside.

It is possible that the flat surface is suitable for forming a solder connection.

Accordingly, it is possible that the inductive element is an SMD element.

For this purpose, it is possible for the terminals of the inductive component to protrude from the body of the component by a certain length, which is suitable for mechanically and electrically connecting the body to conductor structures on a circuit board. In particular, the surfaces of the terminals can be wetted with a solderable material.

It is possible that the electrical conductor has an inductance I, where the inductance I can be ≥ 5 nH and ≤ 470 µH.

It is possible for the inductive element to have a top side and a bottom side, with the bottom side being opposite the one described above. The component can have four recesses on the top side and two recesses on the bottom side. In particular, the four recesses on the top side can each be arranged on one side of a substantially rectangular base area.

Accordingly, it is also preferred if the two recesses on the underside are arranged on opposite sides of the substantially cuboid-shaped body.

It is possible that the body has a magnetic permeability P, where the magnetic permeability P is greater than or equal to 1.5 H/m and less than or equal to 100 H/m.

It is possible that the body of the inductive component comprises a plastic, wherein the plastic is filled with a magnetic material.

Materials that can be used for the plastic and for the magnetic fillings include ferrites or iron alloys for the magnetic material that is mixed into the plastic matrix as a filler.

If the body includes a mold material, the mold material may include or consist of a synthetic resin, e.g. an epoxy.

It is possible that the electrical conductor comprises or consists of a material selected from copper (Cu), silver (Ag), gold (Au) and aluminum (Al).

The recess may have a substantially rectangular, square, round, trapezoidal or oval base.

The base of the recess may contain a flat surface or consist of a flat surface.

A corresponding mold tool for producing an inductive component as described above can comprise an access and a rib.

The access serves as an opening for adding the mold material during the manufacturing process. The rib serves as a support and to fix the central area of the electrical conductor so that it is arranged in its intended position on the finished component with high precision.

It is also possible for the mold tool to have a lower part and an upper part. The lower part can have two ribs and the upper part four ribs - or vice versa. The ribs serve to hold the central area in its position during casting and later reveal themselves as the recesses in the finished inductive component.

Furthermore, the mold tool can have side walls which have a cavity in which the central region of the conductor can be arranged, wherein the side walls define the later outer surfaces of the later component.

• - Bereitstellen eines Mold-Werkzeugs mit einem Zugang und einer Rippe,
• - Bereitstellen des elektrischen Leiters,
• - Positionieren des Zentralbereichs an der Rippe,
• - Umhüllen des Zentralbereichs durch Pressen einer Mold-Masse durch den Zugang

umfassen.A method for the centered embedding of a central region of an electrical conductor can comprise the steps:

• - Providing a mold tool with an access and a rib,
• - Providing the electrical conductor,
• - Positioning the central area on the rib,
• - Enveloping the central area by pressing a mold mass through the access

include.

By using the described mold tool and by applying steps of the described method, an inductive component is obtained whose central region of the electrical conductor is centered with high precision so that precisely defined material thicknesses are obtained on the side walls between the central region and the outer surfaces of the body. This results in an easily manufactured inductive component with precisely defined electrical and magnetic properties.

Functional principles and details of preferred embodiments are explained in more detail using the schematic figures.

• 1: eine perspektivische Ansicht eines induktiven Bauelements,
• 2: eine perspektivische Ansicht eines induktiven Bauelements mit zwei Fasen an der Oberseite,
• 3: eine perspektivische Ansicht der Unterseite des Bauelements,
• 4: einen aufgeschnittenen Körper eines induktiven Bauelements, so dass die Lage und Ausrichtung des elektrischen Leiters erkennbar ist,
• 5: die perspektivische Ansicht eines Zentralbereichs, der eine Spule formt,
• 6: eine perspektivische Ansicht eines Mold-Werkzeugs mit Zugängen zum Applizieren des Mold-Materials,
• 7: einen Querschnitt durch die Anordnung von Mold-Werkzeug und Mold-Material mit Größenangaben einer bevorzugten Ausführungsform.

Show it:

• 1 : a perspective view of an inductive component,
• 2 : a perspective view of an inductive component with two bevels on the top,
• 3 : a perspective view of the underside of the component,
• 4 : a cut-open body of an inductive component so that the position and orientation of the electrical conductor can be seen,
• 5 : the perspective view of a central area forming a coil,
• 6 : a perspective view of a mold tool with access for applying the mold material,
• 7 : a cross-section through the arrangement of mold tool and mold material with size information of a preferred embodiment.

1 shows a perspective view of an inductive component IB with a body K and a first connection AN1 and a second connection AN2. The body K has a substantially cuboid shape and a top O. Furthermore, the body K has a side surface SF. On or in the side surface SF there is a recess The base area of the recess AU is tilted relative to the vertical direction y or relative to the side surface SF, so that a rib R of a mold tool can exert a force component downwards (-y - direction) relative to it and can fix the central region of the electrical conductor relative to a base and relative to a mold material.

In the perspective view, you can see that the connections AN1, AN2 are located on the bottom. These can be provided for SMD mounting, for example.

2 shows a perspective view of inductive component OB with body K. On its edges on the top side O, the essentially cuboid-shaped body K has two bevels F. These beveled surfaces reduce burrs and can simplify further assembly.

The recess has a substantially trapezoidal base, with the edge at the top being longer than the edge at the bottom.

In particular, the recess is shaped in such a way that a rib (possibly better referred to as a lamella or stamp depending on the width) of a mold tool is in direct contact with at least part of the top of the first connection AN1. This allows the latter to be pressed even better with a force onto a base of the mold tool in order to fix the connection and the central area.

3 shows a perspective view of the inductive component IB such that the underside U is facing the viewer. It can also be seen that the essentially cuboid-shaped body K has an orientation surface OF instead of an edge, which simplifies orientation and alignment of the component IB by breaking the symmetry.

4 shows a perspective view of an inductive component IB with a section through the body K, so that the position of the electrical conductor inside the body K can be seen.

5 shows a perspective view of the electrical conductor EL, in which the central region ZB contains windings of a coil that are electrically connected in series between the first connection AN1 and the second connection AN2. The connections AN1, AN2 are used to connect the inductive component to an external circuit environment. The shape of the conductor EL in the central region ZB essentially determines the electrical and magnetic properties of the inductive component.

The electrical conductor itself is formed from a strip with a width and a thickness, whereby the thickness is smaller than the width.

The turns of the coil are insulated from each other by the generally dielectric material of the body K.

6 shows a perspective view of a mold tool MW, which has accesses Z, which are designed as holes. The casting compound can be pressed into the cavity behind it via the accesses Z with an appropriate pressure so that the cavity is completely filled without the central region of the electrical conductor being pushed away from its preferred position.

7 shows a cross-section and the presence of the rib R during casting, which holds the central area in its position and at whose position the later recess will be positioned, since the mold mass cannot occupy the volume of the rib R.

List of reference symbols

AN: AN1, AN2

connection, first, second connection

AU

recess, notch

b, h, t

Width, height, depth of a recess

B, H, L

Width, height, length of the body

EL

electrical conductor

F

chamfer

IB

inductive component

K

Body

MW

Mold tool

O

Top

OF

Orientation area

R

Rib, lamella, stamp

SP

Kitchen sink

U

bottom

MW

Mold tool

e.g.

Central area

Z

Access

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely to provide the reader with better information. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• US 9728331 B2 [0003]
• US 4801912 A [0003]
• US 20100219924 A1 [0003]
• US 20120019343 A1 [0003]
• US 20090250836 A1 [0003]

Claims (28)

Inductive component (IB), comprising - an electrical conductor (EL) with a first terminal (A1), a second terminal (A2) and a central region (ZB) which is arranged electrically between the first terminal and the second terminal, - a body (K) in which the central region is arranged, wherein - the central region is centered in the body and - the body has a first or more recess(es) (A) open to the outside. Inductive component according to the preceding claim, in which one or more recesses each enclose an angle β with 0° ≤ β ≤ 20° with the respective side surface. Inductive component according to one of the preceding claims, in which the conductor is formed in the central region into one or more coils (SP). Inductive component according to the preceding claim, wherein the body contains a mold material or consists of a mold material. Inductive component according to one of the preceding claims, wherein the central region is embedded in the body. Inductive component according to one of the preceding claims, wherein the body contains a second or a plurality of second, outwardly open recess(es) which are arranged opposite the first recesses on the body such that the central region is arranged between the first and the second recess. Inductive component according to one of the preceding claims, further comprising further first recesses in the body. Inductive component according to one of the preceding claims, further comprising further second recesses in the body, wherein first and second recesses are arranged on opposite sides of the body. Inductive component according to one of the preceding claims, wherein one or more or all recesses in the vertical direction y have a height h with 0.8*H ≤ h, where H is the height of the body. Inductive component according to one of the preceding claims, wherein one or more or all recesses have a width b with 0.1*L ≤ b ≤ 0.9*L, where L is the length of the body. Inductive component according to one of the preceding claims, wherein one or more or all recesses have a depth t with 0.01*L ≤ t ≤ 0.5*L, where L is the length of the body. Inductive component according to one of the preceding claims, in which the recesses have a width b of 0.1 mm ≤ b ≤ 3.0 mm. Inductive component according to one of the preceding claims, in which the recesses have a depth t of 0.05 mm ≤ t ≤ 3.0 mm. Inductive component according to one of the preceding claims, in which the body has a substantially cuboid shape with edge lengths K1, K2, K3 with 0.2 mm ≤ K1, K2, K3 ≤ 10 mm. An inductive component according to any preceding claim, wherein the body on the top surface has two inclined bevels extending longitudinally on the transverse sides of the top surface. Inductive component according to one of the preceding claims, in which the body has one or two end faces, each with six edges. Inductive component according to one of the preceding claims, in which the body has two side surfaces which are opposite one another in the transverse direction x and which enclose an angle α with 0° < α ≤ 20°. Inductive component according to one of the preceding claims, wherein the first terminal and the second terminal provide an externally accessible, flat surface. Inductive component according to the preceding claim, in which the flat surface is suitable for forming a solder connection. Inductive component according to one of the preceding claims, which is an SMD element. Inductive component according to one of the preceding claims, wherein the electrical conductor has an inductance I and 5 nH ≤ I ≤ 470 µH. Inductive component according to one of the preceding claims with an upper side and an opposite lower side and 1, 2, 3 or 4 recesses on the upper side and 1, 2, 3 or 4 recesses on the lower side. Inductive component according to one of the preceding claims, wherein the body has a magnetic chemical permeability P with 1.5 H/m ≤ P ≤ 100 H/m. Inductive component according to one of the preceding claims, wherein the body comprises a plastic filled with a magnetic material. Inductive component according to one of the preceding claims, wherein the electrical conductor comprises or consists of a material selected from Cu, Ag, Au, Al. Mold tool for producing an inductive component according to one of the preceding claims, comprising an access (Z) and a rib (R). Mold tool according to the preceding claim, comprising a lower part, an upper part, 1, 2, 3 or 4 ribs on the lower part and 1, 2, 3 or 4 ribs on the upper part. Method for the centered embedding of a central region of an electrical conductor, comprising the steps: - providing a mold tool with an access and a rib, - providing the electrical conductor, - positioning the central region on the rib, - enveloping the central region by pressing a mold mass through the access.