Assembly comprising a toroidal throttle and a heat sink

Description

[0001] The present invention relates to an assembly comprising a toroidal choke and a heat sink. State of the art

[0002] Inductors are used in many areas of electrical and electronic power supply, in power electronics, and in low- and high-frequency technology. These inductors are coils made of an electrically conductive material. To increase their inductive reactance, inductors often incorporate a soft magnetic core. A well-known type of inductor with a soft magnetic core is the toroidal inductor. In toroidal inductors, electrical conductors are wound around soft magnetic ring cores. The soft magnetic core increases the inductive reactance of the coil.

[0003] Heat is generated in the toroidal core and the electrical conductors surrounding it, and this heat must be dissipated as efficiently as possible. Cooling the toroidal core is often not considered because a cooling device must not short-circuit the magnetic flux within the core. Furthermore, the toroidal core itself is often difficult to access for a cooling device because it is surrounded by the electrical conductor.

[0004] DE 198 14 897 A1 discloses an assembly according to the preamble of claim 1. EP 3 330 983 A1 and JP 2007 234752 A disclose further assemblies comprising a toroidal inductor with a heat sink. US 2016 / 163445 A1 discloses a T-shaped core with an elliptical cylindrical core and a core plate, wherein cooling channels running centrally through the core are provided for cooling the core. Disclosure of the invention

[0005] According to the invention, an assembly comprising a toroidal inductor and a heat sink is proposed. The toroidal inductor comprises a toroidal core and an electrical conductor surrounding the toroidal core, wherein the toroidal core has an axial direction and a central annular opening, and wherein a first annular surface and a second annular surface facing away from the first annular surface are formed on the toroidal core, wherein the assembly further comprises a heat sink made of thermally conductive material with a top surface, wherein the toroidal inductor is arranged on the top surface of the heat sink and the second surface of the toroidal core faces the top surface of the heat sink.According to the invention, cooling elements are formed on the cooling body which project from the top of the cooling body, wherein recesses are formed in the ring core, wherein each of the cooling elements is arranged in one of the recesses of the ring core and thus projects into the ring core. Advantages of the invention

[0006] Compared to the prior art, the assembly according to the invention has the advantage that the cooling elements in the recesses of the toroidal core allow heat to be dissipated from the core to the heat sink particularly well and easily. The assembly enables cost-effective and highly efficient cooling of the toroidal core and thus of the toroidal inductor. Cooling of the toroidal inductor can advantageously be carried out within the assembly without eliminating the magnetic flux in the coil.

[0007] Further advantageous embodiments and developments of the invention are made possible by the features specified in the dependent claims.

[0008] According to an advantageous embodiment, the cooling elements are rod-shaped. Rod-shaped cooling elements are particularly easy to manufacture. Furthermore, rod-shaped cooling elements can be inserted particularly easily into the complementary recesses in the ring core, and the assembly can therefore be manufactured particularly easily.

[0009] According to an advantageous embodiment, each cooling element has an outer surface that is complementary to an inner surface of the toroidal core in the recess in which the respective cooling element is arranged, so that each cooling element is in indirect and / or direct contact with the inner surface of the toroidal core in the associated recess. This creates an advantageously large contact area between the cooling elements and the toroidal core, enabling particularly efficient heat transfer from the toroidal core to the cooling elements and thus to the heat sink. This allows for particularly efficient heat dissipation from the toroidal core inductor.

[0010] According to an advantageous embodiment, the outer surfaces of the cooling elements and the inner surfaces of the ring core are cylindrical. This results in particularly simple shapes that can be produced, for example, by simple drilling. The cooling elements can be inserted and fitted into the recesses with particular ease.

[0011] According to an advantageous embodiment, the cooling elements extend from the top of the heat sink into the recesses parallel to the axial direction of the toroidal core. This ensures that the magnetic flux in the toroidal core is not eliminated. Simultaneously, the assembly can be manufactured by simply inserting or pressing the cooling elements into the recesses in the toroidal core.

[0012] According to an advantageous embodiment, the recesses in the toroidal core are formed around the central annular opening. This ensures that the recesses, and thus the cooling elements, are well distributed across the toroidal core, allowing heat to be dissipated evenly from all areas of the core, from the toroidal core choke, to the heat sink.

[0013] According to an advantageous embodiment, the cooling elements are arranged in a circle in a plane perpendicular to the axial direction, with the circle being concentric to the ring core. This minimizes disturbance to the magnetic flux in the ring core while still ensuring very high heat dissipation through a large number of cooling elements.

[0014] According to an advantageous embodiment, the cooling elements are arranged to protrude perpendicularly from a flat support surface on the top of the heat sink, the support surface being arranged parallel to the second surface of the ring core and being spaced from the second surface by a gap, with the electrical conductor passing through the gap.

[0015] According to an advantageous embodiment, the recesses are designed as blind holes. Such a ring core can be manufactured particularly easily by drilling. Furthermore, the cooling elements can be inserted into such recesses with particular ease. The base of the recesses can also serve as a stop for the cooling elements. This increases the contact area between the cooling elements and the ring core and can also be used to define the gap between the second surface and the bearing surface.

[0016] According to an advantageous embodiment, the cooling elements are designed to project into the toroidal core by at least 50%, preferably at least 75%, and particularly preferably at least 90% of its axial extent. This ensures particularly good heat dissipation from the toroidal core. Brief description of the drawings

[0017] Exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description. They show Fig. 1 an embodiment of the assembly according to the invention, Fig. 2 a cross-section through the exemplary embodiment of the assembly according to the invention, Fig. 3 a further cross-section through the exemplary embodiment of the assembly according to the invention. Embodiments of the invention

[0018] Fig. 1 , Fig.2 and Fig.3 show an embodiment of the assembly 1 according to the invention. Fig. 1 A three-dimensional view of the exemplary embodiment of assembly 1 is shown. Fig.2 A section along the axial direction A shows the embodiment of assembly 1. Fig. 3Figure 1 shows a section through an embodiment of assembly 1 perpendicular to the axial direction A. Assembly 1 can be used, for example, as a common-mode or differential-mode choke in a variety of power electronic components, such as inverters or DC / DC converters. Assembly 1 can be used, for example, in filters with common-mode chokes built using can-type or pot-type transformer topology. The toroidal choke 5 can be used, for example, in passive electrical filters to suppress unwanted high-frequency interference. Another application, not according to the invention, is its use as a transformer.

[0019] Assembly 1 comprises a toroidal inductor 5 and a heat sink 20, which is provided for cooling the toroidal inductor 5. The toroidal inductor 5 comprises a toroidal core 10.

[0020] The ring core 10 is, for example, formed in the form of a ring or toroid. The ring core 10 has an axial direction A. The ring core 10 has a central annular opening 18. A first annular surface 11 and a second annular surface 12 are formed on the ring core 10. The first annular surface 11 faces away from the second annular surface 12. The annular surfaces 11, 12 extend in a ring shape around the central annular opening 18. The annular surfaces 11, 12 are spaced apart from each other in the axial direction A by the extent a of the ring core 10. In this embodiment, the annular surfaces 11, 12 are planar and, for example, parallel to each other. The annular surfaces 11, 12 are congruent with each other. The annular surfaces 11, 12 bound the toroidal ring core 10 in the axial direction A.

[0021] The toroidal core 10 is made of a soft magnetic material. Soft magnetic materials are classified according to the IEC 60404-1 standard. For example, the toroidal core 10 can be a ferrite or powder core, or it can consist of crystalline or amorphous metal strips. The toroidal core 10 forms a closed magnetic circuit, with the magnetic flux propagating almost exclusively within the ring-shaped core 10.

[0022] In addition to the toroidal core 10, the toroidal inductor 5 also includes an electrical conductor 6. The electrical conductor 6 is wound, for example, around the toroidal core 10. The toroidal inductor 5 can, for example, include only one electrical conductor 5, but it can also include several electrical conductors 5 wound around the toroidal core 10. Thus, the electrical conductor 6 together with the toroidal core 10 forms a toroidal coil, which is also referred to, for example, as a ring coil or ring coil.

[0023] The heat sink 20 is made of a thermally conductive material, for example, aluminum. Cooling elements 22 are formed on the heat sink 20. The cooling elements 22 are integrally formed with the heat sink 20. The cooling elements 22 project from a top surface 21 of the heat sink 20 towards the toroidal inductor 5. They project into the toroidal core 10 of the toroidal inductor 5. For this purpose, recesses 14 are formed in the toroidal core 10, complementary to the cooling elements 22. The recesses 14 are cavities in the toroidal core 10 that extend from the second surface 12 of the toroidal core 10 towards the first surface 11 of the toroidal core 10. The recesses 14 can be designed as blind holes, as in the embodiment shown in the figures, so that they are open on the second surface 12 but closed on the first surface 11.The recesses 14 can also be designed as through holes and be open on both the second surface 12 and the first surface 11.

[0024] Each cooling element 22 projecting from the top 21 of the heat sink 20 extends into a recess 14 of the toroidal core 10, the recesses of which are complementary to the respective cooling element 22. The cooling elements 22 and the recesses 14 are, for example, cylindrical in shape. The cooling elements 22 have cylindrical outer surfaces 23. The toroidal core 10 has cylindrical inner surfaces 15 that define the recesses 14. The inner surfaces 15 of the toroidal core 10 are in direct contact with the cooling elements 22. Thus, heat can be conducted from the toroidal core 10 to the outer surfaces 23 of the cooling elements 22 via the inner surfaces 15 of the toroidal core 10. The toroidal core 10 therefore surrounds the cooling elements 22 in the plane E perpendicular to the axial direction A.

[0025] In the embodiment shown in the figures, the cooling elements 22 are rod-shaped. The longitudinal axes of the rod-shaped cooling elements 22 are aligned parallel to the axial direction A. The longitudinal axes of the rod-shaped cooling elements 22 are all parallel to each other.

[0026] The cooling elements 22 are arranged around the central annular opening 18. In the plane E perpendicular to the axial direction A, the cooling elements 22 are arranged in a circle. This circle can be arranged concentrically to the annular surfaces 11, 12, as in the embodiment shown in the figures. The cooling elements 22 are arranged in the circle in the plane E with equal intervals between successive cooling elements 22.

[0027] The cooling elements 22 project into the annular core 10 in the axial direction A. The distance a between the plane-parallel arranged annular surfaces 11, 12 is measured in the axial direction A. The cooling elements 22 can, for example, project into the annular core 10 parallel to the axial direction A from the second surface 12 to at least 50% of the distance a. The cooling elements 22 can, for example, also project into the annular core 10 parallel to the axial direction A to at least 75% of the distance a from the second surface 12 to at least 90% of the distance a from the second surface 12 to the annular core 10 parallel to the axial direction A. However, the cooling elements 22 can also project through the annular core 10 from the second surface 12 parallel to the axial direction A to the first surface 11.

[0028] Of course, further embodiments and hybrid forms of the illustrated embodiments are possible, provided they fall within the scope of protection of the claims.

Claims

1. Assembly (1) comprising a toroidal-core inductor (5), wherein the toroidal-core inductor (5) comprises a toroidal core (10) and an electrical conductor (6) surrounding the toroidal core (10), wherein the toroidal core (10) has an axial direction (A) and a central toroid opening (18), and wherein a first annular surface (11) and a second annular surface (10), which faces away from the first annular surface (11), are formed on the toroidal core (12), wherein the assembly (1) further comprises a heat sink (20) which is composed of thermally conductive material and which has a top side (21), wherein the toroidal-core inductor (5) is arranged on the top side (21) of the heat sink (20) and the second surface of the toroidal core (12) faces towards the top side (21) of the heat sink (20), wherein, on the heat sink (20), there are formed cooling elements (22) which project from the top side (21) of the heat sink (20), characterized in that recesses (14) are formed in the toroidal core (10), wherein each of the cooling elements (22) is arranged in in each case one of the recesses (14) of the toroidal core (10) and in this way projects into the toroidal core (10).

2. Assembly according to Claim 1, characterized in that the cooling elements (22) are of rod-shaped form.

3. Assembly according to either of the preceding claims, characterized in that each of the cooling elements (22) has an outer surface (23) which is formed in a manner complementary to an inner surface (15) of the toroidal core (10) in the recess (14) in which the respective cooling element (22) is arranged, so that each cooling element (22) is in indirect and / or direct contact at its outer surface (23) with the inner surface (15) of the toroidal core (10) in the associated recess (14).

4. Assembly according to Claim 3, characterized in that the outer surfaces (23) of the cooling elements (22) and the inner surfaces (15) of the toroidal core (10) are of cylindrical form.

5. Assembly according to one of the preceding claims, characterized in that the cooling elements (22) extend into the recesses (14) away from the top side (21) of the heat sink (20) parallel to the axial direction (A) of the toroidal core (10).

6. Assembly according to one of the preceding claims, characterized in that the recesses (14) in the toroidal core (10) are formed around the central toroid opening (18).

7. Assembly according to one of the preceding claims, characterized in that, when seen in a plane (E) perpendicular to the axial direction (A), the cooling elements (22) are arranged in a circle, wherein the circle is formed in particular concentrically with respect to the toroidal core (10).

8. Assembly according to one of the preceding claims, characterized in that the cooling elements (22) project perpendicularly from a planar bearing surface on the top side (21) of the heat sink (20), wherein the bearing surface is arranged parallel to the second surface (12) of the toroidal core (10) and is spaced apart from the second surface (12) by a gap, wherein the electrical conductor (6) runs through the gap.

9. Assembly according to one of the preceding claims, characterized in that the recesses (14) are in the form of blind holes.

10. Assembly according to one of the preceding claims, characterized in that the cooling elements (22) project into the toroidal core (10) by at least 50%, preferably by at least 75%, particularly preferably by at least 90%, of the extent (a) of the toroidal core (10) in the axial direction (A).