Coil Arrangement and Torque Sensor with Coil Arrangement

Abstract

A coil arrangement has a first cylindrical coil having a first winding direction and a second cylindrical coil having a second winding direction. The first and second cylindrical coils are arranged in longitudinal succession aligned on a common axis. Mutually adjacent ends of the first and second cylindrical coils are electrically connected to each other, and the second winding direction is opposed to the first winding direction.

Claims

1. A coil arrangement for detecting a magnetic field, comprising: a first cylindrical coil with a first winding direction; and a second cylindrical coil with a second winding direction, wherein first and second cylindrical coils are arranged longitudinally one behind another aligned on a common axis, wherein mutually adjacent ends of the first and second cylindrical coils are electrically connected to each other, and wherein the second winding direction is opposed to the first winding direction.

2. The coil arrangement of claim 1 further comprising a stabilizing body for stabilizing alignment of the first and second cylinder coils with respect to each other on the common axis, wherein the stabilizing body is preferably made of plastic material, and wherein the stabilizing body preferably has a constant cross-section along its length.

3. The coil arrangement of claim 1, wherein the first cylindrical coil is provided with a first ferromagnetic coil core and the second cylindrical coil is provided with a second ferromagnetic coil core, wherein first and second coil cores are arranged longitudinally one behind the other and aligned spaced apart on the common axis.

4. The coil arrangement of claim 3, wherein the first ferromagnetic coil core and the second ferromagnetic coil core are embedded in a stabilizing body, the stabilizing body having a longitudinal groove in which the first and second ferromagnetic coil cores are embedded, or wherein the first and second ferromagnetic coil cores are embedded completely enclosed by a material of the stabilizing body.

5. The coil arrangement of claim 3, wherein the first and second ferromagnetic coil cores are one or both of made of a same material and formed the same.

6. The coil arrangement of claim 1, wherein one or more of: a first number of turns of the first cylindrical coil is equal to a second number of turns of the second cylindrical coil; a first winding diameter of the first cylindrical coil is equal to a second winding diameter of the second cylindrical coil; a first length of the first cylindrical coil is equal to a second length of the second cylindrical coil; and an inductance of the first cylindrical coil and an inductance of the second cylindrical coil are equal.

7. The coil arrangement of claim 1, wherein the first winding direction is clockwise and the second winding direction is counterclockwise, or wherein the first winding direction is counterclockwise and the second winding direction is clockwise.

8. The coil arrangement of claim 1, wherein the coil arrangement comprises a coil winding of a winding wire having a first sub-coil winding as a first cylindrical coil and a second sub-coil winding as a second cylindrical coil, wherein the first sub-coil winding has the first winding direction and the second sub-coil winding has the second winding direction.

9. The coil arrangement of claim 8, wherein the coil winding is wound on a stabilizing body as a winding body for winding the winding wire.

10. A measuring device comprising the coil arrangement of claim 1, and further comprising: an AC voltage module for generating an AC voltage, wherein the AC voltage is configured to be applied to the coil arrangement by electrically connecting opposite ends of the first and second cylindrical coils to the AC voltage module.

11. The measuring device of claim 10, wherein the measuring device is provided for detecting a magnetic field.

12. The measuring device of claim 10, wherein the AC voltage is greater than 1 kHz.

13. A torque sensor, comprising: a magnetized shaft, a magnetized disk or a magnetized spoke of a spoke wheel to which a torque is applied, wherein a magnetic field which varies as a function of the applied torque can be generated outside the magnetized shaft, the magnetized disk or the magnetized spoke; and the measuring device according to claim 10 for detecting the generated magnetic field.

14. A device comprising the torque sensor of claim 13, wherein the device is selected from a group comprising a vehicle, a robotic device, a bottom bracket, an e-bike.

15. A method of manufacturing a coil arrangement, comprising: providing a first cylindrical coil having a first winding direction and a second cylindrical coil having a second winding direction longitudinally aligned in series on a common axis, wherein: mutually adjacent ends of the first and second cylindrical coils are electrically connected to each other on the common axis; the second winding direction is opposed to the first winding direction; and providing the first and second cylindrical coils comprises: (i) winding a winding wire to produce a coil winding having a first sub-coil winding as the first cylindrical coil and a second sub-coil winding as the second cylindrical coil, the first sub-coil winding being wound with a first winding direction and the second sub-coil winding being wound with a second winding direction, the winding with the second winding direction being opposed to the winding with the first winding direction; or (ii) providing a respective separate first cylindrical coil having said first winding direction and a second cylindrical coil having said first winding direction; electrically connecting ends of said first and second cylindrical coils adjacent to each other on said common axis; providing a stabilizing body for stabilizing the alignment of the first and second cylindrical coils with respect to each other on the common axis, as a winding body for winding the winding wire for alternative (i); and further, for alternative (i), embedding a first coil core and a second coil core within the stabilizing body, wherein the first coil core is at least partially within the first sub-coil winding and the second coil core is at least partially within the second sub-coil winding.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG. 1 shows a first embodiment of the coil arrangement according to the invention.

[0042] FIG. 2 shows a second embodiment of the coil arrangement according to the invention.

[0043] FIG. 3 shows a third embodiment of the coil arrangement according to the invention.

[0044] FIG. 4 shows an embodiment of the measuring device according to the invention and an embodiment of the torque sensor according to the invention.

[0045] FIG. 5 shows a further embodiment of a torque sensor according to the invention.

[0046] FIG. 6 shows a winding body for manufacturing a coil arrangement according to the invention.

DETAILED DESCRIPTION

[0047] FIG. 1 shows a first embodiment 100 of the coil arrangement according to the invention.

[0048] The coil arrangement 100 according to the invention comprises a first cylindrical coil 10 with a first winding direction (clockwise); a second cylindrical coil 20 with a second winding direction (counterclockwise); wherein the first cylindrical coil 10 and the second cylindrical coil 20 are arranged longitudinally one behind the other aligned on a common axis A; wherein mutually adjacent ends 15 of the first cylindrical coil 10 and second cylindrical coil 20 are electrically connected to one another; and wherein the second winding direction (counterclockwise) is opposite to the first winding direction (clockwise). The direction of the first cylindrical coil 10 is a mirror image of the direction of the second cylindrical coil 20.

[0049] The first winding direction can be clockwise and the second winding direction can be counterclockwise, or the first winding direction can be counterclockwise and the second winding direction can be clockwise.

[0050] For example, a measuring device can be connected to the outer ends of the coil arrangement 100 to provide a measuring voltage, so that the coil arrangement 100 is part of an oscillating circuit that is influenced by magnetic fields present in the coil region.

[0051] Due to the different direction of the first cylinder coil 10 and second cylinder coil 20, there is no need to contact the measuring device at the middle ends 15 of the two cylinder coils 10, 20.

[0052] For example, in this embodiment and those described below, a first number of turns of the first cylindrical coil 10 is equal to a second number of turns of the second cylindrical coil 20; a first winding diameter of the first cylindrical coil 10 is equal to a second winding diameter of the second cylindrical coil 20; a first length of the first cylindrical coil 10 is equal to a second length of the second cylindrical coil 20. One or a plurality (in particular all) of these measures further improve the correspondence of the impact of the two cylindrical coils on the measurement. Additionally or alternatively, an inductance of the first cylindrical coil 10 may be equal to an inductance of the second cylindrical coil 20.

[0053] FIG. 2 shows a second embodiment 200 of the coil arrangement according to the invention.

[0054] The coil arrangement 200 of this second embodiment corresponds to that of the first embodiment according to FIG. 1, further comprising a stabilizing body 30 for stabilizing the alignment of the first and second cylindrical coils 10, 20 with respect to each other on the common axis A. The stabilizing body 30 is made of plastic material, for example. The stabilizing body 30 preferably has a constant cross-section along its length. The stabilizing body 30 contacts the first cylindrical coil 10 and the second cylindrical coil 20 and is shown spaced apart in the drawing only to illustrate the arrangement.

[0055] FIG. 3 shows a third embodiment 300 of the coil arrangement according to the invention.

[0056] The coil arrangement 300 of this second embodiment corresponds to that of the second embodiment according to FIG. 2, wherein the first cylindrical coil 10 is provided with a first ferromagnetic coil core 12 and the second cylindrical coil 20 is provided with a second ferromagnetic coil core 22, wherein the first coil core 12 and the second coil core 22 are arranged longitudinally one behind the other and aligned spaced apart on the common axis (see also FIG. 1).

[0057] The coil cores 12, 22 preferably comprise a (highly permeable) ferromagnetic material to enhance existing magnetic fields and increase the sensitivity of the coil arrangement as a measuring coil.

[0058] FIG. 4 shows an embodiment of the measuring device 450 according to the invention and an embodiment 400 of the torque sensor according to the invention.

[0059] In this example, the measuring device 450 according to the invention comprises a coil arrangement 100 (or a coil arrangement 200, 300) according to the invention, and an AC voltage module 60 for generating an AC voltage. An AC voltage may be applied to the coil arrangement 100 (200, 300) by electrically connecting opposite ends of the first and second cylindrical coils to the AC voltage module 60.

[0060] Provision may be made for the measuring device 450 to detect a magnetic field. Here, the applied AC voltage can be greater than 1 kHz, preferably in the range of 1 kHz to 1 GHz, and most preferably in the range of 10 kHz to 1 GHz. A resonant circuit of the measuring device 450 is affected by the magnetic field at the coil arrangement, so that a measurement of the field can be made.

[0061] The torque sensor 400 according to the invention comprises a magnetized shaft 50 with oppositely magnetized regions 51, 52 in the circumferential direction, wherein a torque can be applied to the shaft 50, wherein a magnetic field which varies as a function of the applied torque is generated outside the shaft 50; and the measuring device 450 according to the invention for detecting the generated magnetic field.

[0062] In an alternative, instead of the magnetized shaft 50, a magnetized disk with different magnetization directions can be used, as described for example in the European Patent Application No. 21 183 622.6.

[0063] The torque sensor 400 according to the invention can be used, for example, in a vehicle, such as an e-bike, in particular a bottom bracket therein, or a robotic device.

[0064] FIG. 5 shows a further embodiment of a torque sensor according to the invention 500.

[0065] In this embodiment of the torque sensor 500, a spoke 95 of a spoke wheel 90 is magnetized, in this example within two radially offset regions of the spoke 95, and magnetized therein in opposite radial directions respectively. The spoked wheel 95 may be substantially in the form of a disc. A torque may be applied to the spoke wheel 90 between an inner portion 91 of the spoke wheel 90 to an outer portion 92 of the spoke wheel 90 by means of force transmitting elements attachable thereto. This torque causes a magnetic field change.

[0066] The torque sensor 500 further comprises a measuring device for detecting the changed magnetic field with a coil arrangement 100, 200, 300 provided at the magnetized radial regions of the spoke 95, wherein the coil arrangement 100, 200, 300 may be formed according to any of the previously described embodiments.

[0067] FIG. 6 shows a winding body 600 for manufacturing a coil arrangement according to the invention.

[0068] One way to provide a coil arrangement according to the invention is to make a coil winding from a winding wire having a first sub-coil winding as a first cylindrical coil and a second sub-coil winding as a second cylindrical coil, wherein the first sub-coil winding has the first winding direction and the second sub-coil winding has the second winding direction. In this way, the coil arrangement can be formed by winding a winding wire (e.g. enameled copper wire). Only the winding direction changes in a transition area between the first and second sub-coil winding.

[0069] The coil wrap may be wound on the winding body 600 shown in FIG. 6 for winding the winding wire. The winding body 600 also includes the stabilizing element 30 with the ferromagnetic cores 12, 22.

[0070] The winding body 600 further comprises positioning elements 71, 72, 73 for positioning the coil arrangement. By using the positioning elements 71, 72, 73, a length of the coil winding or a position of the first and second sub-coil winding can be defined by winding the first sub-coil winding in the region between the positioning elements 71 and 72 in a first winding direction (counterclockwise or clockwise) and winding the second sub-coil winding between the positioning elements 72 and 73 in a second winding direction (clockwise or counterclockwise), which is opposed to the first winding direction. In the transition area with the positioning element 72, the winding wire is passed through in a straight line. The winding wire can protrude from the end portions with the positioning elements 71, 73 so that they can serve as contact points for connecting to a measuring circuit.

[0071] Furthermore, the finished coil arrangement with the positioning elements 71, 72, 73 can be fixed/positioned in a designated measuring area of a device, for example on a circuit board or on a housing of a measuring device.

[0072] The method according to the invention in this example comprises winding a winding wire to produce a coil winding having a first sub-coil winding as the first cylindrical coil and a second sub-coil winding as the second cylindrical coil, the first sub-coil winding being wound with a first winding direction and the second sub-coil winding being wound with a second winding direction, the winding with the second winding direction being opposed to the winding with the first winding direction.

[0073] Further, provision is made in this embodiment for embedding a first and a second coil core 12, 22 within the stabilizing body 30, wherein the first coil core 12 is at least partially within the first sub-coil winding and the second coil core 22 is at least partially within the second sub-coil winding.

[0074] The stabilizing body 30 can, for example, have a longitudinal groove in which the first and second ferromagnetic coil cores 12, 22 are embedded, or the first and second ferromagnetic coil cores 12, 22 can be embedded completely enclosed by the material of the stabilizing body, in particular cast therein.

[0075] The embodiments shown are merely exemplary and the full scope of the present invention is defined by the claims.