Inductive component, mold tool and embedding method

Abstract

The invention relates to an easily manufacturable inductive component with precisely adjustable electrical and magnetic properties. The inductive component comprises a body with a central region of an electrical conductor. The central region is centred in the body. In addition, the body has one or more outwardly opening recesses.

Description

[0001] Description

[0002] INDUCTIVE COMPONENT, MOLD TOOL AND METHOD FOR EMBEDDING

[0003] 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.

[0004] Inductive components can be used in electrical circuits, where they implement inductive circuit elements. The inductance of such components is 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.

[0005] For example, inductive elements with a holder for the coil are known from publications US 9,728,331 B2, US 4,801,912 A, or US 2010 / 0219924 A1. Complex process steps for manufacturing inductive components are known from US 2012 / 0019343 A1 or US 2009 / 0250836 A1.

[0006] However, there is still a desire for inductive components that can be produced using simple, easy-to-perform manufacturing steps and that exhibit precisely adjustable magnetic properties. Likewise, an inductive component is desirable in which contact terminals for connection to an external circuit environment are precisely located and aligned.

[0007] For this purpose, an inductive component or a molding tool and a method for embedding an electrical conductor are specified according to the independent claims. Dependent claims specify advantageous embodiments.

[0008] The inductive component comprises an electrical conductor . The electrical conductor has a first terminal and a second terminal . Furthermore, the electrical conductor has a central region . The central region is arranged between the first terminal and the second terminal . Furthermore, the inductive component has a body in which the central region is arranged . The central region is centered in the body . Furthermore, the body has a first recess open to the outside .

[0009] 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 defined with high precision. As a result, the magnetic environment of the central region of the electrical conductor is essentially defined with high precision, so that the electrical and magnetic properties of the inductive element can be adjusted with high precision. The presence of the outwardly open recess is directly related to the high precision adjustable inductance.The outwardly opening recess serves to hold the electrical conductor, and in particular its central region, in the intended position during the manufacturing process of the inductive component. Mold materials can then be used to surround the central region, ensuring secure fixation of the central region even at high mold pressures. The position within the body and thus the thicknesses of the body material in the various directions around the central region are thus firmly defined, resulting in the high precision of the adjustability of the electrical-magnetic properties of the inductive component.

[0010] The central region of the electrical conductor is essentially the region of the conductor that largely determines the electrical or magnetic properties of the inductive component.

[0011] It is possible for one or more recesses to enclose an angle ß with the respective side surface, where 0° < ß < 20°. 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 for this purpose, with the opening of the area pointing downwards. I.e. the opening of the "V" points downwards.

[0012] It is possible for the electrical conductor in the central region to be formed into one or more coils. The electrical conductor may consist of one or more wires or comprise a wire whose corresponding section is formed into turns that form the coil(s) of the inductive component.

[0013] 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 inductive component on different sides of the 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).

[0014] The coil can have essentially circular windings. The coil can, in particular, be a cylindrical coil or a planar coil. However, it is also possible for the coil windings to have an oval cross-section or a rectangular cross-section.

[0015] It is possible that the body of the inductive component, in which the central region is located, contains a molding material or is made of a molding material. Furthermore, it is possible that the central region of the electrical conductor is embedded in the body of the inductive component.

[0016] Embedding by molding (potting) represents a simple method for manufacturing an inductive component. It is possible for the central region and the mold material surrounding the central region to combine to form a monolithic inductive component. The central region of the electrical conductor is in direct contact with the mold material essentially over its entire length.

[0017] It is possible for the body to contain a second recess which is open outwards and which is arranged opposite the first recess on the body in such a way that the central region is arranged between the first and the second recess.

[0018] The importance of the recesses lies in the fact that during production the associated mold tool has correspondingly shaped elements, e.g. ribs or lamellae, which hold the central region of the inductive component in its position during potting. Ribs of the mold tool can press against the central region of the electrical conductor from different directions, e.g. from opposite directions, and thus hold it in an unchangeable position with high precision, even if during molding, i.e. during potting with the potting compound, a high mold pressure is required depending on the mold material. In particular the mold tool has a cavity which is intended to be filled with the mold compound, whereby the filling of the cavity with the mold material forms the subsequent body in which the electrical conductor with its central region is monolithically enclosed.

[0019] The limitation of the cavity of the mold tool on the one hand and the positioning of the central area defined with high precision on the other hand results in an inductive component whose external dimensions can be precisely adjusted and whose central area of ​​the electrical conductor is determined with high precision so that the magnetic environment of the electrical conductor and in particular of the central area is determined with high precision.

[0020] 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 using simple process steps.

[0021] It is possible that the inductive component further comprises further first recesses in the body.

[0022] The number of recesses in the body, i.e. the possible positions or directions from which the central region of the electrical conductor can be fixed during encapsulation, determines the precision with which the central region can be adjusted and the mechanical resistance that the central region can offer when the potting compound is encapsulated. However, the recesses in which the corresponding conductor section of the electrical conductor contains less mold material in its surroundings 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.

[0023] The depths and widths of the recesses are ideally selected so that the necessary mechanical stability for positioning the central area is sufficiently large and the disturbance of the magnetic environment is sufficiently small.

[0024] Accordingly, it is also possible for the inductive component to comprise additional second recesses in the body. The first recesses and the second recesses are arranged essentially on opposite sides of the inductive component.

[0025] By arranging the recesses opposite each other or by arranging 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.

[0026] 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

[0027] body can be between 1 mm and 10 mm.

[0028] In one embodiment, one or more or all recesses have a width b with 0.1*L < bd 0.9*L, where L is the length of the body.

[0029] 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.

[0030] It is possible that the recesses have a width b of 0.1 mm < bd 3.0 mm.

[0031] Accordingly, it is possible that the recesses have a depth t of 0.05 mm < t < 1.0 mm.

[0032] It is possible for the body of the inductive component to have a substantially cuboid shape. The substantially cuboid-shaped body can have edge lengths K1, K2, K3 of 0.2 mm or more and 10 mm or less.

[0033] The body can have a shape that exactly corresponds 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 chamfer. Furthermore, the body can have a side surface that is designed asymmetrically to other side surfaces of the body in order to facilitate orientation of the component, e.g. when connecting it to a circuit board. It is possible for the body to have two oblique chamfers - extending in the longitudinal direction - on the transverse sides of the top side.

[0034] It is possible that the body has one or two faces, each with six edges.

[0035] It is possible that the body has two side faces that are opposite each other in the transverse direction x and that enclose an angle a with 0 ° < a < 20 ° .

[0036] It is possible that the first connection and the second connection provide a flat surface accessible from the outside.

[0037] It is possible that the flat surface is suitable for forming a solder connection.

[0038] Accordingly, it is possible that the inductive element is an SMD element.

[0039] For this purpose, the terminals of the inductive component may protrude from the component body by a certain length, which is suitable for mechanically and electrically connecting the body to conductor structures on a printed circuit board. In particular, the surfaces of the terminals may be coated with a solderable material.

[0040] It is possible for the electrical conductor to have an inductance I, where the inductance I can be > 5 nH and < 470 pH. It is possible for the inductive element to have a top side and a bottom side, where the bottom side is opposite that 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.

[0041] Accordingly, it is also preferred if the two recesses on the underside are arranged on opposite sides of the substantially cuboid-shaped body.

[0042] 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 .

[0043] It is possible that the body of the inductive component comprises a plastic, wherein the plastic is filled with a magnetic material.

[0044] Materials such as ferrites or iron alloys can be used as materials for the plastic and for the magnetic fillings, which are mixed into the plastic matrix as a filler.

[0045] If the body comprises a mold material, the mold material may comprise or consist of a synthetic resin, e.g. an epoxy.

[0046] It is possible for the electrical conductor to comprise or be made 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.

[0047] The base of the recess may contain a flat surface or consist of a flat surface.

[0048] A corresponding mold tool for producing an inductive component as described above can comprise an access and a rib.

[0049] The access serves as an opening for adding the molding material during the manufacturing process. The rib serves as a support and to fix the central area of ​​the electrical conductor, ensuring that it is positioned precisely in the finished component.

[0050] It is also possible for the mold 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 region in position during casting and later reveal themselves as the recesses in the finished inductive component.

[0051] Furthermore, the mold tool can have side walls that form a cavity in which the central region of the conductor can be arranged, wherein the side walls define the future outer surfaces of the subsequent component. A method for the centered embedding of a central region of an electrical conductor can comprise the following steps:

[0052] - Providing a mold tool with an access and a rib,

[0053] - Providing the electrical conductor,

[0054] - Positioning the central area on the rib,

[0055] - Enveloping the central area by pressing a molding mass through the access area.

[0056] By using the described mold tool and 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 achieved 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.

[0057] Functional principles and details of preferred embodiments are explained in more detail using the schematic figures.

[0058] It shows :

[0059] Figure 1 : a perspective view of an inductive component,

[0060] Figure 2 : a perspective view of an inductive component with two bevels on the top side, Figure 3 : a perspective view of the bottom side of the

[0061] Component,

[0062] Figure 4 : a sectioned body of an inductive component so that the position and orientation of the electrical conductor can be seen,

[0063] Figure 5 : the perspective view of a central area forming a coil,

[0064] Figure 6 : a perspective view of a mold tool with access for applying the mold material,

[0065] Figure 7: a cross section through the arrangement of mold tool and mold material with size information of a preferred embodiment.

[0066] Figure 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 side 0. Furthermore, the body K has a side surface SF. A recess AU is arranged on or in the side surface SF. The base surface 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 molding tool can exert a downward force component (-y direction) relative thereto and can fix the central region of the electrical conductor relative to a base and relative to the molding material. The perspective view shows that the connections AN1, AN2 are arranged on the underside. These can be provided, for example, for SMD assembly. Figure 2 shows a perspective view of the inductive component OB with the body K.The essentially cuboid-shaped body K has two chamfers F on its upper side edges 0. These beveled surfaces reduce burrs and can simplify further assembly.

[0067] The recess has a substantially trapezoidal base, with the edge at the top being longer than the edge at the bottom.

[0068] In particular, the recess is shaped such that a rib (or, depending on its width, better referred to as a lamella or stamp) of a molding tool is in direct contact with at least a portion of the upper surface of the first terminal AN1. This allows the terminal to be pressed even more effectively against a base of the molding tool to secure the terminal and the central region.

[0069] Figure 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 the orientation and alignment of the component IB by breaking the symmetry.

[0070] Figure 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.

[0071] Figure 5 shows a perspective view of the electrical

[0072] Conductor EL, in which the central region ZB contains windings of a coil that are electrically connected in series between the first terminal AN1 and the second terminal AN2. The terminals AN1 and AN2 serve to connect the inductive component to an external circuit. The shape of the conductor EL in the central region ZB essentially determines the electrical and magnetic properties of the inductive component.

[0073] The electrical conductor itself is formed from a strip with a width and a thickness, whereby the thickness is smaller than the width.

[0074] The turns of the coil are insulated from each other by the generally dielectric material of the body K.

[0075] Figure 6 shows a perspective view of a molding tool MW having access points Z formed as holes. Through the access points Z, the potting compound can be pressed into the cavity behind it with appropriate pressure so that the cavity is completely filled without forcing the central region of the electrical conductor away from its preferred position.

[0076] Figure 7 shows a cross-section and the presence of the rib R during casting, which holds the central area in its position and at which the subsequent recess will be positioned, since the molding mass cannot occupy the volume of the rib R. List of reference symbols

[0077] AN: AN1, AN2 : connection, first, second connection

[0078] AU: Recess, notch b, h, t: Width, height, depth of a recess

[0079] W, H, L: width, height, length of the body

[0080] EL: electrical conductor

[0081] F: Chamfer

[0082] IB: inductive component

[0083] K: Body

[0084] MW: Mold tool

[0085] 0: Top

[0086] OF: Orientation surface

[0087] R: rib, lamella, pistil

[0088] SP: Coil

[0089] U: bottom

[0090] MW: Mold tool

[0091] E.g.: Central area

[0092] Z : Access

Claims

Patent claims 1. Inductive component (IB) comprising - an electrical conductor (EL) having a first terminal (Al), a second terminal (A2) and a central region (ZB) which is electrically arranged between the first terminal and the second terminal, - a body (K) in which the central region is arranged, wherein - the central area is centered in the body and - the body has a first or several outwardly open recess(es) (A).

2. Inductive component according to the preceding claim, in which one or more recesses each enclose an angle ß with the respective side surface with 0° < ß < 20°.

3. 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).

4. Inductive component according to the preceding claim, wherein the body contains a mold material or consists of a mold material.

5. Inductive component according to one of the preceding claims, wherein the central region is embedded in the body.

6. Inductive component according to one of the preceding claims, wherein the body contains a second or more second, outwardly open recess (s) which are arranged opposite the first recesses on the body such that the Central area is arranged between the first and second recesses.

7. Inductive component according to one of the preceding claims, further comprising further first recesses in the body.

8. 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.

9. 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.

10. Inductive component according to one of the preceding claims, wherein one or more or all recesses have a width b with 0.1*L < bd 0.9*L, where L is the length of the body.

11. Inductive component according to one of the preceding claims, wherein one or more or all recesses have a depth t with 0.01*L < td 0.5*L, where L is the length of the body.

12. 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.

13. Inductive component according to one of the preceding claims, in which the recesses have a depth t of 0.05 mm dtd 3.0 mm.

14. Inductive component according to one of the preceding claims, in which the body has a substantially cuboid shape with edge lengths Kl, K2, K3 with 0.2 mm < Kl, K2, K3 < 10 mm.

15. An inductive component according to any preceding claim, wherein the body has two oblique bevels extending longitudinally on the transverse sides of the top surface.

16. Inductive component according to one of the preceding claims, in which the body has one or two end faces, each with six edges.

17. 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 a with 0° < a < 20°.

18. Inductive component according to one of the preceding claims, wherein the first terminal and the second terminal provide an externally accessible, flat surface.

19. Inductive component according to the preceding claim, in which the flat surface is suitable for forming a solder connection.

20. Inductive component according to one of the preceding claims, which is an SMD element.

21. Inductive component according to one of the preceding claims, in which the electrical conductor has an inductance I and 5 nH < I < 470 pH.

22. 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.

23. Inductive component according to one of the preceding claims, wherein the body has a magnetic permeability P with 1.5 H / m < P < 100 H / m.

24. Inductive component according to one of the preceding claims, wherein the body comprises a plastic filled with a magnetic material.

25. 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.

26. Mold tool for producing an inductive component according to one of the preceding claims, comprising an access (Z) and a rib (R).

27. 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.

28. A 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 area on the rib, - Enveloping the central area by pressing a molding mass through the access.

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