MAGNETIC SENSOR, SENSOR ARRANGEMENT AND METHOD FOR DETERMINING THE POSITION OF A MAGNETICALLY ACTIVE ELEMENT

Abstract

A magnetic sensor, a sensor arrangement including a magnetic sensor of this type, and a method for determining the position of a magnetically active element. In the sensor, multiple measuring coils are connected in series along a path, such that the position of a magnetically active element along the path can be measured.

Claims

1. A magnetic sensor for detecting a magnetically active element, comprising: which has a multiplicity of measuring coils, wherein each measuring coil has a magnetic core assigned to it, wherein the measuring coils are disposed along a path, wherein the measuring coils are connected electrically in series along the path, and wherein the measuring coils have respective inductances, which increase in one direction along the path.

2. The magnetic sensor as claimed in claim 1, which is configured to produce a common output signal depending on a position of the magnetically active element along the path.

3. The magnetic sensor as claimed in claim 2, wherein the magnetically active element is a ferromagnetic highly permeable body, an electrically conductive body, or a permanent magnet.

4. The magnetic sensor as claimed in claim 1, wherein the respective magnetic cores have no remnant magnetization.

5. The magnetic sensor as claimed in claim 1, wherein the measuring coils are disposed on a printed circuit board, a leadframe, or a molded interconnected devices carrier.

6. The magnetic sensor as claimed in claim 1, wherein each measuring coil is constructed of deposited and structured and/or laminated layers of a metal, in particular a light metal, copper, or an alloy with nickel and/or palladium, and a ferromagnetic material.

7. The magnetic sensor as claimed in claim 1, wherein the measuring coils are spaced so closely apart from one another that during movement of a magnetically active element along the path a characteristic curve of the total inductance is obtained, which is monotonically increasing or decreasing at least over half of the path.

8. A sensor arrangement, comprising: a magnetic sensor as claimed in claim 1, a magnetically active element, and a guide for the magnetically active element, wherein the guide is configured in such a manner that the magnetically active element is movable along the path.

9. The sensor arrangement as claimed in claim 8, wherein the magnetically active element has an actuating member, by which the magnetically active element is movable from outside the guide along the path.

10. The sensor arrangement as claimed in claim 8, wherein the magnetically active element is a ferromagnetic highly permeable body, an electrically conductive body, or a permanent magnet.

11. The sensor arrangement as claimed in claim 8, further comprising a measuring circuit for determining a total inductance of the measuring coils.

12. A method for determining the position of a magnetically active element, the method comprising: arranging the magnetically active element above the magnetic sensor as claimed in claim 1 along the path, measuring a total inductance of the measuring coils, and determining a position of the magnetically active element based on the total inductance.

13. The method as claimed in claim 12, further comprising varying the position of the magnetically active element along the path.

14. The method as claimed in claim 12, wherein the magnetically active element is a ferromagnetic highly permeable body, an electrically conductive body, or a permanent magnet.

15. The method as claimed in claim 12, wherein the sensor is part of a sensor arrangement comprising: the magnetic sensor; the magnetically active element; and a guide for the magnetically active element, wherein the guide is configured in such a manner that the magnetically active element is movable along the path.

16. The magnetic sensor as claimed in claim 1, which is configured to produce a common output signal, in particular a total inductance, depending on a position of the magnetically active element along the path.

17. The magnetic sensor as claimed in claim 1, wherein each measuring coil is constructed of deposited and structured and/or laminated layers of a light metal, copper, or an alloy with nickel and/or palladium, and a ferromagnetic material.

18. The sensor arrangement as claimed in claim 9, wherein the magnetically active element is a ferromagnetic highly permeable body, an electrically conductive body, or a permanent magnet.

19. The magnetic sensor as claimed in claim 1, wherein the measuring coils are spaced so closely apart from one another that during movement of a magnetically active element along the path a characteristic curve of the total inductance is obtained, which is monotonically increasing or decreasing at least least three quarters of the path.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The person skilled in the art will deduce further features and advantages from the exemplary embodiment described hereinafter with reference to the appended drawing.

[0038] In the figures:

[0039] FIG. 1: shows a sensor arrangement with a sensor,

[0040] FIG. 2: shows a characteristic curve of the sensor from FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] FIG. 1 shows a sensor arrangement 10 according to one exemplary embodiment. The sensor arrangement 10 has a sensor 5.

[0042] The sensor 5 has a total of six measuring coils L1, L2, L3, L4, L5, L6, which are mounted on a printed circuit board (not shown). Each of the measuring coils has one core K1, K2, K3, K4, K5, K6 assigned in each case. The cores K1, K2, K3, K4, K5, K6 are not magnetized in the basic state. The measuring coils L1, L2, L3, L4, L5, L6 are connected electrically in series as shown. They are disposed geometrically along a path predefined by their arrangement, which path is straight. For the respective inductances, which are designated the same as the measuring coils, the relationship L1<L2<L3<L4<L5<L6 applies. The inductances therefore increase from left to right. In the present case, each measuring coil has an inductance which is 50% higher compared with the inductance of the measuring coil directly on the left of it.

[0043] The sensor arrangement 10 further comprises a guide 20. The guide 20 is disposed directly above the path predefined by the measuring coils L1, L2, L3, L4, L5, L6. A magnetically active element in the form of a permanent magnet 30 is disposed on the guide 20. The permanent magnet 30 can be displaced in the guide 20 along the path.

[0044] The permanent magnet 30 is connected to an actuating member in the form of a rod 35. The rod 35 can be connected to a component whose movement relative to the sensor 5 is to be measured. A movement of the component (not shown) is transmitted via the rod 35 to the permanent magnet 30, which moves accordingly along the path in the guide 20.

[0045] The sensor arrangement 10 further comprises a measuring circuit 40, which is designed in a known manner. The measuring circuit 40 is configured to measure the total inductance of the measuring coils L1, L2, L3, L4, L5, L6 connected in series.

[0046] FIG. 2 shows a typical characteristic curve of the sensor 5 from FIG. 1. A dimensionless quantity s is plotted on the horizontal axis as a measure for the displacement of the permanent magnet 30 along the path. A likewise dimensionless quantity M is plotted on the vertical axis as a measure for a value measured by the measuring circuit 40. Here this comprises a value which is calculated from the total inductance of the sensor 5. As shown, the characteristic curve is monotonically decreasing for values between about s=−20 and s=20. In this range, the respective position of the permanent magnet 30 along the path can be determined directly from the value of M. In this range of the characteristic curve, the sensor 5 is thus suitable for a direct determination of the position of the permanent magnet 30 along the path. As a result, in particular a position of a component connected to the permanent magnet 30 via the rod 35 can be determined. Thus, the sensor 5 can be used as part of the sensor arrangement 10 for measuring relative movements.

[0047] The claims pertaining to the application do not constitute any dispensing with achieving further protection.

[0048] If it is established in the course of the method that a feature or a group of features is not absolutely necessary, an attempt is already being made by the applicant to formulate at least one independent claim which no longer has the feature or the group of features. This can for example comprise a sub-combination of a claim provided at the filing date or a sub-combination of a claim provided at the filing date restricted by further features. Such claims or feature combinations to be newly formulated should be understood as covered by the disclosure of this application.

[0049] It should be further pointed out that configurations, features, and variants of the invention, which are described in the various explanations or exemplary embodiments and/or shown in the figures, can be arbitrarily combined with one another. Individual or several features can be arbitrarily exchanged for one another. Feature combinations formed from these should be understood as covered by the disclosure of this application.

[0050] Back-references in dependent claims are not to be understood as dispensing with achieving an independent specific protection for the features of the back-related subclaims. These features can also be combined arbitrarily with other features.

[0051] Features which are merely disclosed in the description or features which are disclosed in the description or in a claim only in connection with other features can fundamentally be of independent importance essential to the invention. They can therefore be incorporated individually in the claims for delimitation from the prior art.