INDUCTOR AND INDUCTOR ARRANGEMENT

Abstract

An inductor comprises an excitation coil with an excitation coil axis and at least one shielding coil with a respective shielding coil axis. The excitation coil axis and the shielding coil axis define an angle , wherein applies: 60120, preferably 75105, and preferably 8595. The inductor is shielded and enables in an easy and flexible manner the attenuation of electric and magnetic fields.

Claims

1. An inductor, comprising an excitation coil with an excitation coil axis, at least one shielding coil with a respective shielding coil axis, wherein the at least one shielding coil surrounds the excitation coil, wherein the excitation coil is arranged in a shielding coil interior of the at least one shielding coil, wherein the at least one shielding coil extends through an excitation coil interior of the excitation coil, wherein the excitation coil axis and the respective shielding coil axis define an angle , wherein applies: 60120.

2. An inductor according to claim 1, wherein the angle is defined in a projection plane, which runs in parallel to the excitation coil axis.

3. An inductor according to claim 1, wherein the excitation coil is a solenoid and the excitation coil axis is a straight line.

4. An inductor according to claim 1, wherein the respective shielding coil axis is a curved line and surrounds the excitation coil axis at least partially.

5. An inductor according to claim 1, wherein the at least one shielding coil is a toroid and the respective shielding coil axis is a circular arc.

6. An inductor according to claim 1, wherein the at least one shielding coil has shielding coil windings which have an oval shape.

7. An inductor according to claim 1, wherein a core is arranged in an excitation coil interior of the excitation coil and the at least one shielding coil extends between the core and the excitation coil.

8. An inductor according to claim 1, wherein the excitation coil and the respective shielding coil are fixed relative to each other by an insulating material.

9. An inductor according to claim 1, wherein the at least one shielding coil forms at least one shielding coil layer, wherein for a number N of the at least one shielding coil layer applies: 1N8.

10. An inductor according to claim 1, wherein the excitation coil and the at least one shielding coil are encased by a metal enclosure.

11. An inductor arrangement, comprising an inductor comprising an excitation coil with an excitation coil axis, at least one shielding coil with a respective shielding coil axis, wherein the at least one shielding coil surrounds the excitation coil, wherein the excitation coil is arranged in a shielding coil interior of the at least one shielding coil, wherein the at least one shielding coil extends through an excitation coil interior of the excitation coil, wherein the excitation coil axis and the respective shielding coil axis define an angle , wherein applies: 60120, a reference node, wherein at least one pin of the at least one shielding coil is connected to the reference node.

12. An inductor arrangement according to claim 11, wherein the at least one pin is connected via a capacitor to the reference node.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 shows an inductor arrangement according to a first embodiment of the invention,

[0032] FIG. 2 shows a front view of an inductor in FIG. 1, but only with an excitation coil and a shielding coil and without a core and a metal enclosure,

[0033] FIG. 3 shows a top view of the inductor in FIG. 2,

[0034] FIG. 4 shows a schematic view of the positioning of the excitation coil and the shielding coil in FIG. 3,

[0035] FIG. 5 shows a diagram of an electric field strength E depending on a radial distance x from an excitation coil axis,

[0036] FIG. 6 shows a diagram of an attenuation A of the electric field depending on a frequency f and a diameter d of a shielding coil wire,

[0037] FIG. 7 shows an inductor arrangement according to a second embodiment of the invention,

[0038] FIG. 8 shows an inductor arrangement according to a third embodiment of the invention, wherein the shielding coil forms several shielding coil layers,

[0039] FIG. 9 shows an inductor arrangement according to a fourth embodiment of the invention with a first shielding coil and a second shielding coil, and

[0040] FIG. 10 shows a schematic view of the positioning of the excitation coil and the shielding coils in FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] FIGS. 1 to 6 show a first embodiment of the invention. An inductor arrangement 1 comprises an inductor 2 and a reference node R which is formed by a metal base 3 and connected to ground. For example, the metal base 3 is connected to a chassis of a vehicle.

[0042] The inductor 2 comprises an excitation coil 4, a shielding coil 5, a magnetic core 6 and a metal enclosure 7. The metal enclosure 7 is shown in FIG. 1 merely partially.

[0043] The excitation coil 4 has several excitation coil windings E.sub.1 to E.sub.n which limit an excitation coil interior 8 and define an longitudinal excitation coil axis 9. N is the number of excitation coil windings. The excitation coil 4 is a solenoid. The associated excitation coil axis 9 is arranged concentrically in the excitation coil interior 8 and has the shape of a straight line. The excitation coil 4 has a first pin p.sub.E and a second pin p.sub.E.

[0044] 25

[0045] The shielding coil 5 has several shielding coil windings S .sub.1 to S.sub.m which limit a shielding coil interior 10 and define a curved longitudinal shielding coil axis 11. M is the number of shielding coil windings. The shielding coil 5 is a toroid and the shielding coil axis 11 has the shape of a circular arc. The shielding coil 5 surrounds the excitation coil 4 such that the excitation coil 4 is arranged in the shielding coil interior 10. Hence, the shielding coil axis 11 which is a curved line in the shape of a circular arc concentrically surrounds the excitation coil axis 9. Since the shielding coil 5 surrounds the excitation coil 4 the shielding coil windings S.sub.1 to S.sub.m extend through the excitation coil interior 8 and have an oval shape. The oval shape depends on an axial length of the excitation coil 4 and the number n of excitation coil windings E.sub.1 to E.sub.n. The shielding coil windings S.sub.1 to S.sub.m extend through the excitation coil interior 8 and are arranged in a radial direction between the magnetic core 6 and the excitation coil 4.

[0046] The excitation coil 4 and the shielding coil 5 define in a projection plane P an angle , wherein applies: 60120, preferably 75105, and preferably 8595. The protection plane P runs in parallel to the excitation coil axis 9. For example, the angle =90. The angle describes a rotation or a rotational displacement between the excitation coil axis 9 and the shielding coil axis 11.

[0047] The excitation coil 4 has in relation to a plane which runs perpendicular to the excitation coil axis 9 a pitch angle .sub.E, whereas the shielding coil 5 has in relation to a plane which runs perpendicular to the shielding coil axis 11 a pitch angle .sub.s. Depending on the pitch angles .sub.E and .sub.s the excitation coil windings E.sub.1 to E.sub.n and the shielding coil windings S.sub.1 to S.sub.m define an angle , wherein applies: 30150, preferably 45135, and preferably 60120.

[0048] The shielding coil 5 has a first pin p.sub.1 and a second pin p.sub.1. The first pin p.sub.1 is connected to the reference node R, whereas the second pin p.sub.1 is not connected at all.

[0049] The excitation coil 4, the shielding coil 5, the magnetic coil 6 and the metal enclosure 7 are fixed relative to each other by an insulating material 15. The insulating material 15 is shown in FIG. 1 merely partially. For example, the insulating material 15 is resin which fixes the mentioned components by curing.

[0050] The shielding coil 5 forms exactly one shielding coil layer L.sub.1. Therefore, for a number N of shielding coil layers applies: N=1. The shielding coil 5 has a shielding coil wire with a diameter d, wherein applies: 0.01 mmd3.2 mm, preferably 0.05 mmd1.0 mm, preferably 0.06 mmd0.6 mm, preferably 0.09 mmd0.2 mm

[0051] FIG. 5 shows the strength of the electric field (E-field) depending on the radial distance from the excitation coil axis 9. The x-coordinate is the radial distance from the excitation coil axis 9, whereas the y-coordinate is the strength of the electric field E. E.sub.0 shows the strength of an electric field of the excitation coil 4 without the shielding coil 5. E.sub.1 shows the strength of the electric field of the described inductor arrangement 1. E.sub.2 shows the strength of the electric field in case that the second pin p.sub.1 is connected to the reference node R as well. The shielding coil 5 effectively reduces the radiation of the electric field and hence the radiation of the resulting magnetic field as well.

[0052] FIG. 6 shows a diagram of the attenuation A of the electric field depending on the frequency f for a first diameter d.sub.1 of the shielding coil wire and a second diameter d.sub.2 of the shielding coil wire, wherein d.sub.1>d.sub.2. For example, the shielding coil wire is of copper. A thickness D of the shielding coil layer L.sub.1 is dependent on and equal to the diameter d of the shielding coil wire. The diameter d of the shielding coil wire is adapted to the desired attenuation A at a desired frequency f. When the desired attenuation frequency increases, the skin depth decreases. Hence, the diameter d of the shielding coil wire decreases as well.

[0053] FIG. 7 shows an inductor arrangement according to a second embodiment of the invention. In difference to the first embodiment the first pin p.sub.1 is connected via a first capacitor C.sub.1 to the reference node R and the second pin p.sub.1 is connected via a second capacitor C.sub.2 to the reference node R. The capacitors C.sub.1 and C.sub.2 enable to adapt the attenuation of electric and magnetic fields to a desired band of frequency. Further details concerning the design and functioning of the inductor arrangement 1 can be found in the description of the first embodiment.

[0054] FIG. 8 shows an inductor arrangement 1 according to a third embodiment of the invention. In difference to the proceeding embodiments the shielding coil 5 has a number N=3 of shielding coil layers L.sub.1 to L.sub.N. The shielding coil layers L.sub.1 to L.sub.N form a thickness D which depends on the diameter d of the shielding coil wire and the number N. The number N of shielding coil layers L.sub.1 to L.sub.N, the thickness D of shielding coil layers L.sub.1 to L.sub.N and the diameter d of the shielding coil wire is adapted to the desired attenuation of electric and magnetic fields at a desired frequency. E.sub.i denotes one of the excitation coil windings E.sub.1 to E.sub.n, whereas S.sub.j denotes one of the shielding coil windings S.sub.1 to S.sub.m. Further details concerning the design and the functioning of the inductor arrangement 1 can be found in the descriptions of the proceeding embodiments.

[0055] FIGS. 9 and 10 show an inductor arrangement 1 according to a fourth embodiment of the invention. In difference to the proceeding embodiments the inductor arrangement 1 comprises a first shielding coil 5 and a second shielding coil 12. The second shielding coil 12 has several shielding coil windings S.sub.1 to S.sub.k which limit a second shielding coil interior 13 and define a second longitudinal shielding coil axis 14. The excitation coil 4 and the first shielding coil 5 are arranged in the second shielding coil interior 13. The second shielding coil 12 is a toroid and the second shielding coil axis 14 is a curved line in the shape of a circular arc which surrounds the excitation coil axis 11. The second shielding coil windings S.sub.1 to S.sub.k extend through the excitation coil interior 8 and have an oval shape which depends on the axial length of the excitation coil 4.

[0056] The excitation coil axis 9 and the first shielding coil axis 11 define the angle , whereas the excitation coil axis 9 and the second shielding coil axis 14 define a corresponding angle . For the angle applies as well: 60120, preferably 75105, and preferably 8595. Preferably, = applies. The second shielding coil 12 has a second pitch angle .sub.s. The excitation coil windings E.sub.1 to E.sub.n and the second shielding coil windings S.sub.1 to S.sub.k define an angle which depends on the pitch angles .sub.E and .sub.s. For the angle applies: 30150, preferably 45135, and preferably 60120.

[0057] The shielding coils 5, 12 form a number N=2 of shielding coil layers L.sub.1 to L.sub.N. The first pin p.sub.1 of the first shielding coil 5 and a first pin p.sub.2 of the second shielding coil 12 are connected to the reference node R. The second pin p.sub.1 of the first shielding coil 5 and a second pin p.sub.2 of the second shielding coil 12 are not connected. Further details concerning the design and functioning of the inductor arrangement 1 can be found in the descriptions of the proceedings embodiments.

[0058] The features of the inductor arrangements 1 and the associated inductors 2 can be combined with one another as desired to achieve the desired attenuation of electric and magnetic fields at a desired frequency and the desired shielding effectiveness.