Abstract
A device for determining the angle of a rotating component is provided. The device includes a magnetostrictive sensor structure which is coupled to a transmitter and at least one receiver, and along which a magnet is secured to the moving component moves. The transmitter and the receiver(s) are connected to an electronic analysis unit for determining the position of the moving component based on a transit time between the transmitter and a saturation zone and back from the saturation zone to the receiver(s). The transmitted signal is reflected on the saturation zone produced in the magnetostrictive sensor structure by the magnet.
Claims
1. A device for determining an angle of a rotating component, comprising a magnetostrictive sensor structure, which is coupled to a transmitting element and a receiving element and along which a magnet secured to the rotating component moves, wherein the transmitting element and the receiving element are connected to evaluation electronics for determining a position of the rotating component from a transit time between the transmitting element and a saturation zone and back from the saturation zone to the receiving element, wherein a transmitted signal is reflected at the saturation zone produced by the magnet in the magnetostrictive sensor structure, wherein the magnetostrictive sensor structure comprises two sensor loops located at a mutual spacing and the shape of each sensor loop is adapted to a movement direction of the rotating component, wherein the transmitting element is provided for simultaneously coupling a pulse into each of the two sensor loops, in a vicinity of which the receiving element for each sensor loop is positioned to receive the pulse reflected by the saturation zone of the respective sensor loop, wherein the receiving element is connected to the evaluation electronics to determine an angular position of the rotating component from a ratio of two transit times in the two sensor loops.
2. The device as claimed in claim 1, wherein a spacing of the magnet from the magnetostrictive sensor structure determines a width of the saturation zone.
3. The device as claimed in claim 1, wherein the magnet is positioned such that it is tilted with respect to the magnetostrictive sensor structure.
4. The device as claimed in claim 1, wherein the magnet secured to the rotating component is formed as a magnetic ring or from two opposing block magnets.
5. The device as claimed in claim 1, wherein the magnetostrictive sensor structure is arranged in an electronic element generating the pulse and comprising the evaluation electronic.
6. The device as claimed in claim 5, wherein the magnetostrictive sensor structure is formed in a printed circuit board on which the electronic element generating the pulse and comprising the evaluation electronics is positioned.
7. The device as claimed in claim 1, wherein the sensor loops each comprise two curved sensor elements.
8. The device as claimed in claim 7, wherein the curved sensor elements of the two sensor loops are formed to be semicircular, wherein the semicircular sensor elements of a sensor loop are arranged with respect to one another to resemble a circle.
9. The device as claimed in claim 8, wherein end pairs of the semicircular sensor element of the sensor loops are arranged offset from one another by 90.
10. The device as claimed in claim 1, wherein the curved sensor elements of the sensor loops are formed in a meandering manner.
11. A device for determining an angle of a rotating component, the device comprising: a magnetostrictive sensor structure coupled to a transmitter and one or more receivers and along which a magnet secured to the rotating component moves, the magnetostricture sensor structure including: first and second sensor loops spaced apart, wherein a shape of each sensor loop corresponds to a direction of movement of the rotating component a first saturation zone in the first sensor loop, and a second saturation zone in the second sensor loop, and evaluation electronics coupled to the transmitter and the receivers, wherein the evaluation electronics are configured to determine an angular position of the rotating component based on a ratio of (i) a first transit time of a first signal in the first sensor loop being transmitted, reflected from the first saturation zone, and received at the one or more receivers, and (ii) a second transit time of a second signal in the second sensor loop being transmitted, reflected from the second saturation zone, and received at the one or more receivers.
12. The device of claim 11, wherein a spacing between of the magnet from the magnetostrictive sensor structure defines a width of the saturation zone.
13. The device of claim 11, wherein the magnet secured to the rotating component is positioned such that it is tilted with respect to the magnetostrictive sensor structure.
14. The device of claim 1.1, wherein the magnet secured to the rotating component includes a magnetic ring or two opposing block magnets.
15. The device of claim 11, wherein the magnetostrictive sensor structure is arranged in an electronic element generating a pulse into each of the first and second sensor loops and comprising the evaluation electronics.
16. The device of claim 11, wherein the magnetostrictive sensor structure includes a printed circuit board on which the electronic element generates the pulse and the evaluation electronics is positioned.
17. The device of claim 11, wherein the sensor loops each include two curved sensor elements.
18. The device of claim 17, wherein the curved sensor elements of the two sensor loops are semicircular and arranged with respect to one another to resemble a circle.
19. The device of claim 18, wherein a pair of the semicircular sensor elements of the sensor loops are arranged offset from one another by 90.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Several embodiments are explained in more detail with reference to the figures illustrated in the drawing, which show:
[0020] FIG. 1: an operating principle for the transit time measurement,
[0021] FIG. 2: a further operating principle for the transit time measurement,
[0022] FIG. 3: an exemplary embodiment for generating a saturation zone in a magnetostrictive sensor structure,
[0023] FIG. 4: a further exemplary embodiment for generating a saturation zone in a magnetostrictive sensor structure,
[0024] FIG. 5: a further exemplary embodiment for generating a saturation zone in a magnetostrictive sensor structure,
[0025] FIG. 6: an exemplary embodiment for the use of block magnets,
[0026] FIG. 7: an exemplary embodiment for an arrangement of the magnetostrictive structure,
[0027] FIG. 8: a further exemplary embodiment for the arrangement of the magnetostrictive structure,
[0028] FIG. 9: an exemplary embodiment of a magnetostrictive sensor structure for a 360 sensor,
[0029] FIG. 10: a further exemplary embodiment of a magnetostrictive sensor structure for a 360 sensor,
[0030] FIG. 11: a further exemplary embodiment of a magnetostrictive sensor structure for a 360 sensor,
[0031] FIG. 12: an exemplary embodiment of a magnetostrictive sensor loop.
DETAILED DESCRIPTION
[0032] FIG. 1 illustrates a first exemplary embodiment of an operating principle for transit time measurement with a magnetostrictive displacement transducer, which measures an angle of a rotating component. The magnetostrictive displacement transducer 1 serves for measuring the distance between two points 2, 3 between which a waveguide, formed as a magnetostrictive sensor structure 4, is arranged, along which waveguide a permanent magnet 5 moves. A respective current pulse is coupled into the magnetostrictive sensor structure 4 at the points 2, 3. The current generates a circular magnetic field, which is concentrated in the magnetostrictive sensor structure 4 owing to the magnetically soft properties thereof. At the displacement point to be measured, the movable permanent magnet 5 is used as a position encoder whereof the magnetic field lines extend at a right angle to the pulse magnetic field and are likewise concentrated in the magnetostrictive sensor structure 4. In the region of the magnetostrictive sensor structure 4 in which both magnetic fields are superimposed, an elastic deformation is produced by magnetostriction, which corresponds to a saturation zone 6. The pulses which are supplied in each case into the points 2, 3 are reflected at this saturation zone 6. The reflected pulses are received again at the points 2 and 3, and their transit time determined. The position of the permanent magnet 5 which is secured to the rotating component is concluded from the ratio of the two transit times.
[0033] FIG. 2 shows a further operating principle for the transit time measurement, in which a plurality of points 2, 3, 7 are used for pulse coupling and measurement. In this case, each point 2, 3, 7 corresponds to a predetermined angle, for example the point 7 to an angle of 0, the point 3 to an angle of 180 and the point 2 to an angle of 360. Pulses are coupled at each point 2, 3, 7 in opposite directions of the magnetostrictive sensor structure 4 and reflected by the saturation zones 6, 8 produced in each case between two points 2, 3 or 3, 7 in the sensor structure 4. Since a fixed angular position is associated with the supply and, at the same time, receiving points 1, 2 and 7 in each case, the position of the permanent magnet 5 can be concluded redundantly from the different transit time measurements.
[0034] FIG. 3 illustrates an exemplary embodiment for generating the saturation zone of the magnetostrictive sensor structure 4. In this case, the magnetostrictive sensor structure 4 is secured on a printed circuit board 9. Opposite this, the permanent magnet 5 is arranged centrically with respect to the axis of rotation 12, wherein the left side represents the south pole S and the right side the north pole N. Saturation zones 6, 8 form in the manner already described, wherein these saturation zones 6, 8 are understood to refer to a magnetization whereof the value is not exceeded by an increase in the outer magnetic field strength.
[0035] With a centric arrangement of the permanent magnet 5 in relation to the magnetostrictive sensor structure 4, saturation zones 6, 8 with the same width are produced in the signal of the reflected pulse. This width of the saturation zones 6, 8 can vary due to a change in the spacing between the permanent magnet 5 and the magnetostrictive sensor structure 4, as illustrated in FIG. 4. The left of FIG. 4 shows a greater spacing between the permanent magnet 5 and the magnetostrictive sensor structure 4, whereby both pulses have a smaller saturation spacing. If the permanent magnet 5 is moved closer to the magnetostrictive sensor structure 4, as illustrated in the left of FIG. 4, the saturation zone 6, 8 widens as a result of a higher flux density in the magnetostrictive sensor structure 4.
[0036] Different widths of the saturation zones 6, 8 can be set by tilting the permanent magnet 5 with respect to the magnetostrictive sensor structure 4, as clarified in FIG. 5. In this case, the tilting of the permanent magnet 5 produces asymmetrically wide saturation zones 6, 8.
[0037] In the examples above, it was assumed that the permanent magnet 5 is a magnetic ring which is secured to the rotating component for which the position is to be detected. However, the use of a continuous magnetic field progression, as generated by the magnetic ring, is not essential for the angular measurement. Therefore, instead of the magnetic ring, two block magnets 10, 11 can also be arranged opposite the magnetostrictive sensor structure 4, which block magnets have an opposing polarity in their positions and the same spacing from the axis of rotation 12. Via these two block magnets 10, 11, only two saturation zones 6, 8 for the pulse measurement are generated, which are produced with the opposing arrangement of the two block magnets 10, 11.
[0038] FIG. 7 shows an exemplary embodiment for the arrangement of the magnetostrictive sensor structure 4. In this case, the sensor structure 4 is illustrated in simplified form as a ring and has points 1, 2, 7 at predetermined spacings for coupling two pulses running in opposite directions and for receiving the reflected pulses. Such a sensor structure 4 is formed in a chip 13, wherein the center of the chip 13 is formed by an electronic unit 14 for pulse generation and evaluation. In this case, the sensor structure 4 surrounds the electronic unit 14. Such a chip 13 is secured on the printed circuit board 9. Since fixed angular degrees are associated with the predetermined points 2, 3, 7, as already explained above, pulse coupling and the receipt of the reflected pulses takes place, for example, at 00 and at 360, wherein the saturation zones 6, 8 produced by the permanent magnets 5 are located between 0 and 1800 or 180 and 360 of the sensor structure 4. By arranging the sensor structure 4 in the chip 13, a universally formed chip is realized, which can be adapted to a wide variety of applications.
[0039] In an alternative exemplary embodiment, as illustrated in FIG. 8, the chip 13, which supports the electronic unit 14 for pulse generation and pulse evaluation, is positioned on the printed circuit board 9 whilst the sensor structure 4 is formed within the printed circuit board 9 and connected to the chip 13.
[0040] FIG. 9 illustrates an exemplary embodiment of a magnetostrictive sensor structure 4 of a 360 sensor. For such a sensor, the sensor structure consists of two sensor loops 15, 16, wherein each sensor loop 15, 16 comprises two semicircular sensor elements 15.1, 15.2 or 16.1, 16.2. The two sensor elements 16.1, 16.2 of the inner sensor loop 16 are arranged approximately circularly. The same applies to the two sensor elements 15.1, 15.2 of the outer sensor loop 15, which surround the inner sensor loop 16. In this structure, two saturation zones 6, 8 are generated by the permanent magnets 5 (not illustrated further), which saturation zones comprise the two sensor loops 15, 16. The mutually opposing ends 15.3, 15.4; 16.3, 16.4 of the two sensor elements 15.1, 15.2; 16.1, 16.2 of a sensor loop 15, 16 therefore always form an end pair with which a transmitting element 17 is associated. In this case, a separate receiver 18, 19 for receiving the reflected pulses is associated with each end 15.3, 15.4; 16.3, 16.4 of the sensor element 15.1, 15.2; 16.1, 16.2. In the present case, two pulses are each coupled into an end pair 15.3, 15.4; 16.3, 16.4 in opposite directions by the transmitting element, which pulses are reflected back by the saturation zone 6, 8 produced in the corresponding sensor element 15.1, 15.2; 16.1, 16.2. A redundant system is produced when two sensor loops 15, 16 are used for the position measurement.
[0041] FIG. 10 shows a further exemplary embodiment for a 360 sensor. In this case, FIG. 10a again shows the redundant system already explained in connection with FIG. 9, in which the saturation zones 6, 8 are located outside the ends 15.3, 15.4; 16.3, 16.4 of the sensor elements 15.1,15.2; 16.1, 16.2. However, if, as illustrated in FIG. 10b, the saturation zones 6, 8 are located at the level of the transmitting element 17, as denoted for the inner sensor loop 16, the pulses of the transmitting element 17 are not reflected since each pulse is detected immediately by the receiver 18, 19. The inner sensor loop 16 can therefore not be used for the measurement. A position of the rotating component can only be determined via the outer sensor loop 15.
[0042] To prevent dead zones, a further exemplary embodiment of the sensor structure 4 is illustrated in FIG. 11. In this case, both the outer 20 and the inner sensor loop 21 have only one curved sensor element, although each sensor element extends over more than 180. In this case, the ends 20.1; 21.1 of the inner and outer sensor element 20, 21 which point in opposite directions are each supplied by only one transmitting unit 17. The mutually opposing saturation zones 6, 8 comprise only the inner sensor loop 21 (saturation zone 8) in one case and only the outer sensor loop 20 (saturation zone 6) in one case, as illustrated in FIG. 11a. In this arrangement, both the outer and the inner sensor loop 20, 21 can measure in both directions, from which reliable position determination is realized. In the structure shown in FIG. 11b, the respective saturation zone 6, 8 is formed directly behind the receiver 18 of the inner sensor loop 21 in one case and directly behind the receiver 19 of the outer sensor loop 20 in one case, wherein the saturation zones 6, 8 cover both the inner and the outer sensor loop 20, 21. This has the effect that both the inner and the outer sensor loop 20, 21 can only measure in one direction since the transmitting unit 17 is blocked by the respective saturation zone 6, 8. In this case, the coupling by the transmitting unit 17 takes place at only one end of the outer sensor loop 20 and at the opposite end of the inner sensor loop 21. A prerequisite for the measurement via such a sensor structure is that the two sensor loops 20, 21 are always formed to be larger than the saturation zones 6, 8.
[0043] FIG. 12 illustrates two exemplary embodiments for a magnetostrictive sensor structure 22, 23 for lengthening the pulse transit distance. Since the transit time is generally in the nanosecond range, the short time is usually difficult to evaluate. The evaluation is improved if the transit distance is increased. This takes place by configuring the sensor loop 22 as a meandering structure, which enables a continuous lengthening of the sensor loop 22. FIG. 12b illustrates a meandering sensor loop 23, via which discrete pulses can be generated. By lengthening the transit time, the tolerance of the time measurement has less effect on signal errors.
[0044] With the aid of the proposed solution, angular measurement of a rotating component is enabled, in which, through variations in the two saturation zones, the tolerance of the magnetic field strength, the spacing between the magnet and sensor structure, wobbling of the magnetic ring and temperature variations can remain disregarded.
LIST OF REFERENCE SIGNS
[0045] 1 Magnetostrictive displacement transducer [0046] 2 Coupling and measuring point [0047] 3 Coupling and measuring point [0048] 4 Magnetostrictive sensor structure [0049] 5 Permanent magnet [0050] 6 Saturation zone [0051] 7 Coupling and measuring point [0052] 8 Saturation zone [0053] 9 Printed circuit board [0054] 10 Block magnet [0055] 11 Block magnet [0056] 12 Axis of rotation [0057] 13 Chip [0058] 14 Electronic unit [0059] 15 Sensor loop [0060] 15.1 Sensor element [0061] 15.2 Sensor element [0062] 15.3 End of the sensor element [0063] 15.4 End of the sensor element [0064] 16 Sensor loop [0065] 16.1 Sensor element [0066] 16.2 Sensor element [0067] 16.3 End of the sensor element [0068] 16.4 End of the sensor element [0069] 17 Transmitting unit [0070] 18 Receiver [0071] 19 Receiver [0072] 20 Sensor loop [0073] 21 Sensor loop [0074] 22 Magnetostrictive sensor structure [0075] 23 Magnetostrictive sensor structure
