Inductive component, and method for producing an inductive component

Abstract

The invention relates to an inductive component comprising: a wire winding; a base plate made of magnetically conductive material; and at least two electrically conductive connection surfaces on a bottom side of the base plate for SMT (Surface Mounted Technology) mounting, the wire winding being in the form of a flat spiral winding, the wire winding being arranged on a top side of the base plate, and two U-shaped clips being provided with two limbs and a base connecting the limbs, the U-shaped clips being positioned on the base plate such that each first limb is positioned on the top side of the base plate and each second limb is positioned on the bottom side of the base plate, at least one portion of each second limb forming a connection surface, and a first winding end of the wire winding being connected to the first limb of the first clip, and a second winding end of the wire winding being connected to a first limb of the second clip.

Description

[0001] Inductive component and method for producing an inductive component

[0002] The invention relates to an inductive component with a wire winding and a method for producing an inductive component.

[0003] For contactless energy transfer, particularly for charging electronic devices, magnetic fields generated by so-called WPT (Wireless Power Transfer) coils can be used. Wire-wound coils are used for wireless power transfer (WPT) to generate the required power densities. These coils have only two wire connections and are not suitable for SMT (Surface Mounted Technology). As a result, such a wire-wound WPT coil must be manually soldered after an automated soldering process, which is used to attach the other components required on the circuit board. This leads to process uncertainties and generally high manufacturing costs.

[0004] The invention is intended to improve an inductive component with a wire winding and a method for producing an inductive component.

[0005] According to the invention, an inductive component having the features of claim 1 and a method for producing an inductive component having the features of claim 11 are provided. Advantageous developments of the invention emerge from the subclaims.

[0006] An inductive component according to the invention comprises a wire winding, a base plate made of magnetically conductive material, and at least two electrically conductive connection surfaces on an underside of the base plate for SMT (surface-mounted technology) assembly. The wire winding is designed as a flat spiral winding, wherein the wire winding is arranged on an upper side of the base plate and wherein two U-shaped clamps with two legs and a base connecting the legs are provided. The U-shaped clamps are arranged on the base plate such that a first leg is arranged on the upper side of the base plate and a second leg is arranged on the underside of the base plate.At least one section of each second leg forms a connection surface, with a first winding end of the wire winding being connected to the first leg of the first clamp, and a second winding end of the wire winding being connected to a first leg of the second clamp. A wire winding is a winding made of a wire that is electrically conductive and is usually provided with insulation, in particular a lacquer coating, on its outer surface. A wire winding differs from printed windings or stamped windings. The inductive component according to the invention is intended for WPT (Wireless Power Transfer) applications, i.e. the wireless transmission of energy in a comparatively high power range up to the kilowatt range. Such coils for high power ranges can no longer be designed with printed or stamped windings.Because the winding is designed as a flat spiral winding, the inductive component has a very low installation height on a circuit board. A base plate made of magnetically conductive material can conduct the magnetic field generated by the winding and thus ensure very efficient energy transfer using the magnetic field. Two U-shaped clamps are simply arranged on the base plate so that a first leg is located on the top side of the base plate and a second leg is located on the bottom side of the base plate. The first legs on the top side of the base plate serve to electrically connect the winding ends of the wire winding, for example by soldering or mechanical pressing. The second legs arranged on the bottom side of the base plate then form, at least in sections, a connection surface for SMT assembly.Such SMT assembly can be fully automated, in particular. The electrical connection of the winding ends of the wire winding to the respective first legs on the top side of the base plate can also ideally be automated. The invention thus provides an inductive component that can be manufactured and assembled on a circuit board in a largely automated manner, and that is suitable for wireless energy transmission via a magnetic field in high power ranges up to the kilowatt range.

[0007] In a further development of the invention, the base plate is formed at least in sections from ferrite.

[0008] Ferrite is a magnetically conductive material, but not electrically conductive. Ferrite is therefore a highly suitable material for the base plate of the inductive component according to the invention.

[0009] In a further development of the invention, the base plate has a central, in particular circular-cylindrical, elevation, wherein the wire winding surrounds the elevation.

[0010] Such a central, particularly circular-cylindrical, elevation can focus the magnetic field and thus ensure highly efficient energy transfer via the magnetic field. In a further development of the invention, the base plate has an annular projection, with the wire winding arranged within the annular projection.

[0011] In this way, the magnetic field generated by the wire winding can be guided and efficient energy transfer via magnetic field can be ensured.

[0012] In a further development of the invention, an innermost turn of the wire winding is arranged adjacent to the central elevation and an outermost turn of the wire winding is arranged adjacent to the annular projection.

[0013] In this way, an efficient guidance of the magnetic field generated by the wire winding in the base plate can be achieved.

[0014] In a further development of the invention, the clamps each encompass an edge of the base plate in sections.

[0015] The clamps can be easily positioned along the edge of the base plate, for example, simply plugged in. Using the clamps, a simple and extremely reliable reconnection around the edge of the base plate can then be achieved.

[0016] In a further development of the invention, the wire winding is glued to the top of the base plate.

[0017] In this way, the wire winding can be reliably held in position during handling and then also during use of the inductive component, for example in a mobile application.

[0018] In a further development of the invention, the wire winding is embedded in a temperature-resistant plastic material, in particular an adhesive, in particular a synthetic resin.

[0019] Such a temperature-resistant plastic material can be used to achieve both bonding and protection against mechanical damage. Temperature-resistant plastic material can also protect the inductive component during soldering.

[0020] In a further development of the invention, the wire winding is arranged in a housing made of temperature-resistant plastic material. This also provides mechanical fastening, protection against mechanical damage, and protection against high temperatures, for example, during soldering.

[0021] In a further development of the invention, the plastic material in which the wire winding is embedded or from which the housing is made is temperature-resistant up to 300 °C.

[0022] In this way, the inductive component can be soldered automatically in an oven, for example, but also in a solder bath or a soldering wave.

[0023] The object underlying the invention is also achieved by a method for producing an inductive component according to at least one of the preceding claims, in which the adhesive bonding of a wire winding, which is designed as a flat spiral winding, to the upper side of a base plate made of magnetically conductive material, the arrangement of two U-shaped clamps made of conductive material on the base plate, wherein the U-shaped clamps each have a first leg, a second leg and a base connecting the legs, so that the respective first leg rests on an upper side of the base plate and the respective second leg rests on an underside of the base plate, and the electrically conductive connection of a first end of the wire winding to the first leg of the first clamp and the electrically conductive connection of a second end of the wire winding to the first leg of the second clamp is provided.

[0024] In a further development of the invention, the clamps are arranged in such a way that the base of the clamp rests on one edge of the base plate.

[0025] In a further development of the invention, the wire winding is embedded in a temperature-resistant plastic material, in particular a plastic material that is temperature-resistant up to 300 °C.

[0026] In a further development of the invention, the wire winding is arranged in a housing made of temperature-resistant plastic material.

[0027] Further features and advantages of the invention will become apparent from the following description of a preferred embodiment of the invention in conjunction with the drawings. In the drawings:

[0028] Fig. 1 is a view of an inductive component according to the invention from above, Fig. 2 is a plan view of the component according to the invention of Fig. 1,

[0029] Fig. 3 is a side view of the component according to the invention of Fig. 1 and

[0030] Fig. 4 a view of a clamp for the inductive component from the front.

[0031] Fig. 1 shows an inductive component 10 according to the invention, which has a wire winding 12, a base plate 14, and two U-shaped clamps 16, 18. The wire winding 12 is made of round wire as a flat spiral winding. The wire winding 12 is therefore mechanically wound and, in particular, not printed or punched. Within the scope of the invention, the wire winding 12 can, of course, also be made of wire with a rectangular or square cross-section. The wire of the wire winding 12 is provided with an electrical insulation, for example, painted, in an invisible manner, so that no short circuits can occur between adjacent wire pieces or even superimposed wire pieces.

[0032] The wire winding 12 has a first winding end 20, which is electrically connected to the first clamp 16, and a second winding end 22, which is connected to the second clamp 18. The electrically conductive connection between the winding end 20 and the clamp 16, as well as between the winding end 22 and the clamp 18, can be made, for example, by soldering, but also in another way, for example, by welding or the like.

[0033] The clamps 16, 18 are identical to one another and are made of electrically conductive material, such as sheet metal, such as copper sheet. As can be seen in Fig. 4, each of the clamps 16, 18, shown in Fig. 4 using the example of clamp 16, has a U-shape with a first leg 24, a second leg 26, and a base 28 connecting the two legs 24, 26.

[0034] The two clamps 16, 18 are pushed onto an edge of the base plate 14 such that the first leg 24 of the clamp 16 (visible in Fig. 1) and the first leg 24 of the clamp 18 rest on an upper side of the base plate. In the state of Fig. 1, the respective second leg 26 rests on an underside of the base plate 14, which is hidden in Fig. 1. In the state of Fig. 1, the base 28 rests on an outer edge of the base plate 14, whereby the base 28 is hidden in Fig. 1 and therefore not visible. In the state of Fig. 1, the hidden second legs 26 can serve as connection surfaces for the inductive component 10.Since the respective second legs 26 are located on the underside of the base plate 14, the inductive component 10 can be mechanically fastened to a printed circuit board using SMT technology (Surface Mounted Technology), and the connection surfaces formed by the second legs 26 on the underside of the base plate 14 can simultaneously be electrically connected in a simple manner to a connection surface on a printed circuit board (not shown), in particular by soldering.

[0035] The inductive component 10 is designed for wireless power transfer via a magnetic field and, in the illustrated embodiment, is specifically designed for a comparatively high power range of approximately 100 watts up to several kilowatts. For this reason, the wire winding 12 must be wound from a single wire and cannot, for example, be printed or stamped. Lower power levels are feasible within the scope of the invention.

[0036] The base plate 14 is made of ferrite. Ferrite is magnetically conductive and can therefore conduct the magnetic field generated by the wire winding 12. The base plate 14 has a central, circular-cylindrical elevation 30. The base plate 14 also has an annular projection 32 on its outer edge. This annular projection 32 is aligned parallel to the direction of extension of the central elevation 30. However, the annular projection 32 is interrupted in the area of ​​the two clamps 16, 18.

[0037] The magnetic field generated by the wire winding 12 enters or exits upwards in a concentrated manner via the surface of the elevation 30, and an electronic device to which energy is to be transferred can then be arranged above the elevation 30. For this purpose, the electronic device must also have an inductive component to convert the magnetic energy back into electrical energy and then, for example, to charge a battery of the electronic device.

[0038] The underside of the base plate 14 is flat, as can be seen, for example, from the side view of Fig. 3. The base plate 14 can therefore be easily placed on a printed circuit board.

[0039] As already explained, the annular projection 32 of the base plate 14 is interrupted in the area of ​​the two clamps 16, 18. The annular projection 32 terminates at each of its ends in a radially outwardly extending end piece 36, 38. An end piece 36, 38 is arranged on either side of the clamps 16, 18. A stop block 34 is arranged between the two clamps 16, 18. Between the end piece 36 and the stop block 34, the base plate 14 has a section whose thickness is matched to the length of the base 28 of the clamps 16, 18. The same applies to the area between the stop block 34 and the end piece 38. The clamps 16, 18 can thus be pushed onto the edge of the base plate 14 until the inside of the base 28 of the clamps 16, 18 rests against the outer edge of the base plate 14.

[0040] In this position, the clamps 16, 18 can be held by clamping forces; alternatively or additionally, the clamps 16, 18 can be glued to the base plate 14. Once the state shown in Fig. 1 is achieved, i.e., the winding ends 20, 22 are connected to the clamps 16, 18, the wire winding 12 is advantageously embedded in a temperature-stable plastic material, such as an adhesive or a synthetic resin. This glues the wire winding 12 to the top of the base plate 14, and at the same time, the clamps 16, 18 can also be glued to the base plate 14.The wire winding 12 is protected against mechanical damage by being embedded, and the inductive component 10 can also be automatically assembled and soldered, for example, in an oven, a solder bath, or a soldering wave, since the temperature-resistant plastic material in which the wire winding 12 is embedded protects the wire winding 12 and, in particular, the electrical insulation of the wire of the wire winding 12. Furthermore, the wire winding 12 is also protected against mechanical stress.

[0041] Fig. 2 shows a plan view of the inductive component 10 according to the invention. It shows the base plate 14 with the ring-like projection 32 and the central elevation 30, the spiral wire winding 12 on the upper side of the base plate 14 and the two clamps 16, 18.

[0042] Fig. 3 shows a side view of the inductive component 10. This side view shows the outer edge of the base plate 14, which is formed by the annular projection 32. The view in Fig. 3 also shows the radially projecting end piece 38 of the annular projection 32. The illustration in Fig. 3 further shows that the wire winding 12 extends beyond the upper edge of the annular projection 32. The two clamps 16, 18 are hidden in the view in Fig. 3. The end pieces 36, 38 and the stop block 34, see Fig. 1, also serve to mechanically protect the electrical connection of the winding end 20 to the clamp 16 or of the winding end 22 to the clamp 18. For this purpose, the end pieces 34 and the stop block 34 protrude beyond the legs 24 with the winding ends 20, 22 arranged thereon. The legs 24 and the winding ends 20, 22 are therefore concealed in the side view of Fig. 3.The invention provides an inductive component that is suitable for high electrical powers of up to several kilowatts and that is suitable for assembly using SMT technology (Surface Mounted Technology).

[0043] During the manufacture of the inductive component 10 shown in Figs. 1 to 3, the wire winding 12 is first created by winding a wire as a flat spiral winding. This wire winding 12 is then glued to the top side of the base plate 14. To protect the wire winding 12, and in particular the electrical insulation of the wire of the wire winding 12, the entire wire winding can be coated with the temperature-resistant adhesive, for example, embedded in a temperature-resistant synthetic resin.

[0044] The two U-shaped clamps 16, 18 are arranged at the edge of the base plate 14. The two winding ends 20, 22 of the wire winding 12 are then connected, for example, by soldering, to the legs 24 of the clamps 16, 18 located on the upper side of the base plate 14. The wire winding 12 can also be embedded after the winding ends 20, 22 have been electrically connected to the clamps 16, 18.

[0045] The inductive component 10 is completed after these steps. The inductive component 10 can be manufactured fully automatically and can also be fully automatically assembled on a circuit board.

Claims

Patent claims 1. An inductive component comprising a wire winding, a base plate made of magnetically conductive material, and at least two electrically conductive connection surfaces on an underside of the base plate for SMT (Surface Mounted Technology) assembly, wherein the wire winding is configured as a planar spiral winding, wherein the wire winding is arranged on an upper side of the base plate, and wherein two U-shaped clamps having two legs and a base connecting the legs are provided, wherein the U-shaped clamps are arranged on the base plate such that a first leg is arranged on the upper side of the base plate, and a second leg is arranged on the underside of the base plate, wherein at least a portion of the second leg forms a connection surface,wherein a first winding end of the wire winding is connected to the first leg of the first clamp and a second winding end of the wire winding is connected to a first leg of the second clamp., 2. Inductive component according to claim 1, characterized in that the base plate is formed at least in sections from ferrite.

3. Inductive component according to claim 1 or 2, characterized in that the base plate has a central, in particular circular-cylindrical, elevation, wherein the wire winding surrounds the elevation.

4. Inductive component according to one of the preceding claims, characterized in that the base plate has an annular projection, wherein the wire winding is arranged within the annular projection.

5. Inductive component according to claim 3 and claim 4, characterized in that an innermost turn of the wire winding is arranged adjacent to the central elevation and that an outermost turn of the wire winding is arranged adjacent to the annular projection.

6. Inductive component according to at least one of the preceding claims, characterized in that the clamps each engage around an edge of the base plate in sections.

7. Inductive component according to at least one of the preceding claims, characterized in that the wire winding is glued to the upper side of the base plate.

8. Inductive component according to at least one of the preceding claims, characterized in that the wire winding is embedded in a temperature-resistant plastic material, in particular an adhesive, in particular a synthetic resin.

9. Inductive component according to at least one of the preceding claims, characterized in that the wire winding is arranged in a housing made of temperature-resistant plastic material.

10. Inductive component according to claim 8 or 9, characterized in that the plastic material in which the wire winding is embedded or from which the housing is made is temperature-resistant up to 300 degrees Celsius.

11. A method for producing an inductive component according to at least one of the preceding claims, characterized by gluing a wire winding, which is designed as a flat spiral winding, to the upper side of a base plate made of magnetically conductive material, arranging two U-shaped clamps made of conductive material on the base plate, wherein the U-shaped clamps each have a first leg, a second leg and a base connecting the legs, so that the respective first leg rests on an upper side of the base plate and the respective second leg rests on an underside of the base plate, and electrically conductively connecting a first end of the wire winding to the first leg of the first clamp and electrically conductively connecting a second end of the wire winding to the first leg of the second clamp.

12. The method according to claim 11, characterized by arranging the clamps so that the base of the clamps each rests against an edge of the base plate.

13. Method according to claim 11 or 12, characterized by embedding the wire winding in a temperature-resistant plastic material, in particular a plastic material temperature-resistant up to 300 degrees Celsius.

14. Method according to claim 11 or 12, characterized by arranging the wire winding in a housing made of temperature-resistant plastic material.

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