WO2021043644A1

WO2021043644A1 - Sensor assembly for detecting a rotation angle of a flow element

Info

Publication number: WO2021043644A1
Application number: PCT/EP2020/073820
Authority: WO
Inventors: Ajoy Palit; Jörg Grotendorst; Maik Hubert
Original assignee: Zf Friedrichshafen Ag
Priority date: 2019-09-04
Filing date: 2020-08-26
Publication date: 2021-03-11
Also published as: DE102019213389A1

Abstract

The invention relates to a sensor assembly (2) for detecting a rotation angle (D) of a flow element (12), which can be rotated along a circular path (14) about an axis of rotation (10), comprising: at least one coil group (4a, b) each having at least two coils (6a-d) in a plane (16) concentrically surrounding the axis of rotation (10) and positioned in parallel with and along the circular path (14), wherein a respective coil group (4a, b) is limited to a respective coil angle (S1, 2), wherein the coil angles (S1, 2) of all coil groups (4a, b) add up to a total angle (G) of less than 360°; at least one empty region (8a, b) extending over a respective empty angle (E1, 2); the flow element (12) parallel to the plane (16), having an angular extension (W) that is greater than the largest coil angle (S1, 2); and an evaluation device (18) for determining the current inductance (L1-4) of the coils (6a-d) and the current rotation angle (D) based on the inductances (L1-4).

Description

Sensor arrangement for detecting an angle of rotation of a flux element

The invention relates to a sensor arrangement for detecting an angle of rotation of a flux element that is rotatable about an axis of rotation along a circular path.

A rotor position sensor for drive motors, for example of electric vehicles, which is based on the modulation of eddy currents and the use of coil pairs, is from "Development of Eddy-Current Rotor Position Sensor, Markus Simon, Business Unit 8, SUMIDA Components & Modules GmbH , Presented at EVTeCand APE Japan on May 23, 2014, JSAE Paper No. 20144103 "(" 140523_EVTeC_speech.pdf ", download from" https://www.sumida.com/news/index.php7catego- ryld = 3 & newsld = 116 " on June 19, 2019).

The object of the present invention is to propose improvements in relation to a rotation angle detection.

The object is achieved by a sensor arrangement according to claim 1. Preferred or advantageous embodiments of the invention and other inven tion categories emerge from the further claims, the following description and the accompanying figures.

The sensor arrangement is used to detect an angle of rotation of a flux element. The flux element can be rotated about an axis of rotation along a circular path. The sensor arrangement contains at least one, in particular exactly one, in a preferred embodiment at least two coil groups interacting with the flux element. Each of the coil groups contains at least two coils. The interaction comprises a relative rotation between the coil and the flux element by different angles of rotation. Depending on the angle of rotation, a magnetic field generated by the coil generates eddy currents of varying strength in the flux element, so that the inductances of the coil change in each case. These inductances can be measured and thus conclusions can be drawn about the relative position between coil and flux element and thus about the angle of rotation. The coils are in particular flat coils, the flux element is in particular plate-shaped, for example a copper plate or a copper activator. In particular, the coils and flux element are arranged flat parallel to one another or rotatable with respect to one another with the interposition of an in particular narrow air gap.

The coil groups extend in an axis of rotation concentrically surrounding the surface. The orientation of the surface to the axis of rotation can be selected differently, see below. The area runs parallel to the circular path and along the circular path. A respective coil group is limited along the circular path to a respective coil angle, i.e. part of the circumference. The coil group is therefore limited to a certain angular section in the circumferential direction of the axis of rotation, e.g. maximally or exactly to 180 ° (for a coil group) or maximally or precisely to a quadrant of 90 ° (for at least two coil groups).

The coil angles of all coil groups add up to a total angle of less than 360 °. Not the entire circumference around the axis of rotation is occupied by groups of coils. Along the circular path there is therefore at least one empty area (in the embodiment of at least two coil groups: between two coil groups each), in which there is no coil group or coil. The respective empty area extends over a respective empty angle. The sum of all empty angles and the total angle results in the entire circumference of 360 ° around the axis of rotation.

The sensor arrangement also contains the flux element, which extends parallel with the interposition of a spacing gap to the surface and thus to the coils in order to act differently depending on the angle of rotation on the inductances of the coils. The flux element has an angular extent along the circular path that is greater than the largest coil angle.

The sensor arrangement contains an evaluation device which is set up to determine for each of the coils their current inductance (i.e. depending on the relative position between flux element and coil or angle of rotation) and to determine a current angle of rotation of the flux element on the basis of at least two, in particular all, to determine determined inductances. All angles are to be considered as angles with respect to the axis of rotation, ie in the circumferential direction of the axis of rotation, that is, along the circular path.

The invention is based on the knowledge that inductive rotor angular-position measurement sensors (IRPS) require a large circuit board surface when trapezoidal planar coils with a rotational shape have to be printed on an entire ring-shaped circuit board. In addition, such large trapezoidal coils produce the change in inductance signals (which are complex functions of the angular position of the copper activator or target). Therefore, the generated functions of the inductances versus the angle of rotation are not easy to process with inexpensive signal shaping hardware and microcontroller / signal processor. In short, complex signal processing algorithms have to be developed and their implementation requires costly microcontrollers / signal processors (DSP, digital signal processors).

According to the invention, this results in a reduction in the costs for printed circuit boards or coils and a simpler determination of the angle of rotation through a simpler evaluation of the sensor signal or the determined inductances.

The invention can be implemented for both radial and axial versions of sensor arrangements or sensors, see below. The invention can be used in particular for detecting the rotor position of an electric machine or an electric motor, and in particular in e-mobility projects.

In a preferred embodiment - as explained above - at least two coil groups are present, and along the circular path there is at least one empty space between every two coil groups. This results in distributed coil structures which, in particular, can be designed with point / rotation symmetry. In a preferred embodiment, the same number of coil groups and empty areas are arranged alternately along the circular path. As a result, a simple and, from two coil groups, a particularly symmetrical and simple structure is made possible in which coil groups with empty areas always alternate in the circumferential direction around the axis of rotation. This also results in advantages with regard to a flux element that protrudes beyond the coil groups, see below.

In a preferred variant of the embodiment with at least two coil groups, at least two of the coil angles are of the same size and / or at least two of the empty angles are of the same size. In particular, all coil angles are the same size and / or all empty angles are the same size. Alternatively or additionally, at least one, in particular all, coil angles and one, in particular all, empty angles are the same size. This leads to particularly simple arrangements.

In a preferred variant of the embodiment with at least two Spulengrup pen, there are exactly two coil groups and exactly two empty areas. In total, there are thus a minimum of four, in particular exactly four, coils. This results in a particularly simple embodiment. In particular, a two-quadrant arrangement can thus take place, see below.

In a preferred embodiment - in particular the variant with exactly one coil group - the total angle is 180 ° and / or the angular extent is 360 ° and / or at least one of the coil angles is 180 ° and / or at least one of the empty angles is 180 °. For a total angle of 180 °, only half of the circumference around the axis of rotation results as the area required for coils or circuit boards on which coils are arranged. An angular expansion of 360 ° for the flux element is particularly suitable in a 180 ° arrangement of precisely one coil group.

In a preferred variant of the embodiment with at least two coil groups, the total angle is 180 ° and / or the angular extent is 180 ° and / or at least one of the coil angles is 90 ° and / or at least one of the empty angles is 90 °. For a total angle of 180 ° only results Half of the circumference around the axis of rotation as space requirement for coils or printed circuit boards on which coils are arranged. An angular extension of 180 ° for the flow element is particularly suitable in a two-quadrant arrangement, see below. Corresponding 90 ° angles are also suitable for this two-quadrant arrangement, see below.

In a preferred embodiment, the flow element is designed to be contiguous along the circular path. This results in a particularly simple flow element. Alternatively, the flow element is divided into at least two sections. Here again the alternatives arise that at least two of the sections adjoin one another and / or are spaced apart from one another. The flow element can thus have different sections or parts that do not all have to be related; one or more gaps may exist between adjacent sections. Advantages for correspondingly designed flux elements arise depending on the specific arrangement and division of the coil groups.

In a preferred embodiment, the angular extent is at least as large as the largest sum of a coil angle and an adjacent empty angle with the given division for a specific sensor arrangement. This ensures for all angles of rotation that the flux element can always completely cover every pair of adjacent coil groups and empty angles. This leads to a particularly easy evaluation of the angle of rotation from the inductances.

In a preferred variant of the embodiment with at least two coil groups there is at least one type of coil for the same coils and at least two coil groups each contain one of the same coils. These coils are then arranged rotationally symmetrically to the axis of rotation. This is to be understood as meaning that these move apart from one another or are congruent by rotating them by the difference angle of the coil groups. So within the coil type there is a rotation mirroring or rotation of the coils, in particular by an angle of 360 ° divided by the number of coil groups. In particular, four coils are in two coil types provided in two coil groups of two coils each. A particularly simple and homogeneous evaluation of the inductances can be carried out by using the same coils accordingly.

In a preferred variant of this embodiment, a respective section of the flux element is assigned to at least one coil type. In particular, exactly two different coil types are provided, and thus exactly two sections, that is to say one per coil type. This leads to a further homogenization of the evaluation of the inductances.

In a preferred variant of this embodiment, at least one of the sections is congruent with the assigned coil type. In particular, for a certain angle of rotation, the section covers exactly a respective coil of the coil type, that is, it forms a parallel image of the corresponding coil transversely to its direction of extension. Thus, with maximum effect on the inductances of the coil, the dimensions or the transverse extent of the section parallel to the coil are kept as small as possible.

In a preferred embodiment, in at least one of the coil groups, at least two of the coils lie next to one another in the area perpendicular to the circular path. This applies in particular in the radial direction or axial direction of the axis of rotation. This applies in particular to all coil groups and all coils. In particular, different sections which are assigned to corresponding coils or coil types can be arranged particularly favorably in the flux element.

In a preferred embodiment, at least one of the coils has a shape that tapers along the circular path. The tapering relates to a certain direction of rotation with respect to the axis of rotation, in the opposite direction the coil is then designed to widen. In particular, tapering or enlargement for un ferent coils of a coil group are designed in opposite directions, especially in the case of two coils. In this way, particularly favorable inductance curves can be generated over the angle of rotation of the flux element. In a preferred embodiment, at least one of the coil groups has the shape of a circular ring segment or a circumferential section of a circular cylinder jacket. This results in geometrically particularly simple embodiments for the coil groups. In this way, particularly simple geometric shapes are also possible for the flow element. In particular, this embodiment can be combined with the arrangement of the coils “next to one another”.

In a preferred embodiment, the surface has the shape of a disk transverse to the axis of rotation. An axial arrangement can thus be created. Alternatively, the surface has the shape of the jacket of a straight circular cylinder with respect to the axis of rotation. A radial arrangement can thus be created. Alternatively, the surface has the shape of a jacket of a right circular truncated cone with respect to the axis of rotation. This results in a conical "mixed shape" of the arrangement between circular disk and cylinder shape. In this way, a suitable geometry of the sensor arrangement can always be selected for many geometrical requirements.

The invention is based on the following findings, observations and considerations and also has the following embodiments. The embodiments are sometimes also referred to as "the invention" for the sake of simplicity. The embodiments can also contain parts or combinations of the above-mentioned embodiments or correspond to them and / or optionally also include embodiments not mentioned so far.

According to the invention, in particular, planar trapezoidal coils (in rotation form) in a (based on the circumference around the axis of rotation) first semicircular circumference (for a single coil group) or a first and third quadrant (for at least two or exactly two coil groups) of a circular disk (Printed circuit board, PCB, printed circuit board) implemented. Therefore, half of the circuit board area is required compared to a sensor in which the circuit board surrounds the axis of rotation completely dig. This reduces both the size of the sensors and the circuit board costs. A very special form of the flux element is proposed, in particular a copper (Cu) activator element, namely similar, in particular corresponding or the same as the coil contours. The rotary movement of this flux element (Cu activator element) creates a simple "scissors / X-shaped" course of the inductivity L (nH) of the coils over the angle of rotation or a theta (°) rotary position. Due to the simple nature of the inductance curve, an angle position detection algorithm (algorithm for determining the angle of rotation) and its implementation processor (microcontroller) can be used in the form of a low-cost solution.

Further features, effects and advantages of the invention emerge from the following description of a preferred exemplary embodiment of the invention and the attached figures. In each case show in a schematic principle sketch:

Figure 1 two coil groups and two empty areas of a sensor arrangement,

FIG. 2 shows a flow element of the sensor arrangement from FIG. 1,

FIG. 3 shows the assembled sensor arrangement from FIGS. 1, 2 at angles of rotation of the flux element of a) 0 °, b) 90 °, c) 180 ° and d) 270 °.

FIG. 4 shows the course of the inductances of the coils of the sensor arrangement from FIGS. 1-3 over the angle of rotation,

FIG. 5 a) coil groups and empty areas and b) a flux element of an alternative sensor arrangement,

FIG. 6 simulation results for a clockwise rotating flux element, FIG. 7 a status table for a clockwise flux element rotation,

FIG. 8 shows an alternative sensor arrangement with a single coil group.

Figures 1 and 2 together show a disassembled sensor arrangement 2. Figure 1 shows a first part of the sensor arrangement 2, namely two coil groups 4a, b each with two coils 6a-d and two empty areas 8a, b. Each of the coils 6a-d has a respective inductance L1-L4. The sensor arrangement has an axis of rotation 10 which, in FIGS. 1-3, runs perpendicular to the plane of the drawing. FIG. 2 shows a second and thus remaining part of the sensor arrangement 2, namely a flux element 12 which can be rotated about the axis of rotation 10 along a circular path 14. The circular path 14 runs in the plane of the paper in FIG. 2 and is only partially shown. The sensor arrangement 2 serves to detect an angle of rotation D of the flux element 12 about the axis of rotation 10 relative to the part of the sensor arrangement 2 shown in FIG. 1.

The flow element 12 has an angular extent W of 180 ° along the circular path 14.

In the assembled state of the sensor arrangement 2 (see Figure 3), the flow element 12 is only through a spacing gap a symbolically indicated here, here an air gap, separated above (ie facing the viewer in the figure) of the arrangement from Figure 1. Therefore, an interaction occurs between the flux element 12 and the coils 6a-d to the effect that the inductances L1-4 of the coils 6a-d vary depending on the angle of rotation D of the flux element 12.

The coil groups 4a, b extend in a surface 16 concentrically surrounding the axis of rotation 10, which corresponds to the plane of the paper in FIG. 1 and extends transversely to the axis of rotation 10. The surface 16 thus runs parallel to the circular path 14 and also along the circular path 14. The flux element 12 therefore extends parallel to the surface 16 with the spacing gap a between them.

Along the circular path 14, that is to say in the circumferential direction with respect to the axis of rotation 10, both the coil group 4a and the coil group 4b are each limited to a coil angle S1 and S2 of 90 °. Both coil angles S1 and S2 thus add up to a total angle G of 180 °.

The two empty areas 8a, b are each located between the two coil groups 4a, b and extend over a respective empty angle E1 and E2 of 90 ° each. Overall, this results in a two-quadrant arrangement with coils 6a-d in only two quadrants Q1, 3. The angular extent W of 180 ° is at least (or here exactly the same) as large as the largest possible sum of a coil angle (here both S1,2 = 90 °) and an empty angle (here both E1, 2 = 90 °) at the given sensor arrangement 2. The largest sum is thus also 180 °.

An evaluation device 18 of the sensor arrangement 2 is only shown symbolically in FIG. This is set up - here by programming a digital signal processor (not shown) - to determine the current inductances L1-4 or the corresponding inductivity value for each of the coils 6a-d at a certain point in time and to determine a current angle of rotation D of the flux element 12 To determine the basis of the four determined inductances L1-L4. The determination takes place on the basis of technical, essentially simple geometrical or field theoretical considerations corresponding to angle sensors known from practice that basically work in the same way and will not be explained in more detail here.

Figures 1 and 2 thus show a small and compact inductive rotor angular position measurement sensor (Small and Compact Inductive Rotor Angular Position Measurement Sensor: SCIRAMS). In particular, they show an axial type of IRAMS, i.e. an axial IRPS (Inductive Rotor Position Sensor).

Figure 1 shows two small circuit boards 20a, b (PCB) each in the form of a quarter of a disc (quarter circular ring segments), which are in a first quadrant Q1 (angle of rotation 0 ° to 90 °) and third quadrant Q3 (angle of rotation 180 ° to 270 °) are mounted, each on a non-metallic circular disc 22 (circular ring). In the printed circuit board 20a, so in the Q1-PCB, the two trapezoidal coils of the planar type, namely coil 6a or L1 and coil 6b or L2, are printed, which are in the form of rotation (i.e. surrounding the axis of rotation 10 along the circular path 14) . Similarly, in the printed circuit board 20b, i.e. in the Q3-PCB, there are arranged two flat trapezoidal coils, namely coil 6c or L3 and coil 6d or L4, which are also in the form of rotation.

Note that the radially outer coils 6a, c (Q1-PCB and Q3-PCB) are uneven numbered (L1 and L3) and the radially inner coils 6b, d (Q1-PCB and Q3-PCB) are even numbered (L2 and L4). In contrast, the Q2 and Q4 quadrants of the circular disk 22 do not have PCBs and therefore do not contain any planar trapezoidal coils. In addition, the two odd-numbered coils 6a (L1) and 6c (L3) are of the same coil type 24a (geometry / shape / contour, track width, winding spacing and number of turns, etc.), and the two even-numbered coils 6b ( L2) and 6d (L4) of the same coil type 24b (geometry / shape / contour, track width, winding spacing and number of windings, etc.). FIG. 1 thus shows the circular disk 22 which carries PCBs with trapezoidal planar coils 6a-d.

FIG. 2 shows a thin / laminar CU activator in the form of the flow element 12, which slides / rotates just above the trapezoidal coils 6a-d while maintaining a fixed gap (spacing gap a).

In the center, the circular disk 22 has a circular recess or a hole 26 for the assembly (penetration) of a rotor shaft (not shown).

FIG. 2 shows a thin and laminar metallic (made of Cu) semicircular plate in the form of the flow element 12, which functions as an activator / target for the inductive sensor or the sensor arrangement 2. The flow element 12 has two sections A1 and A2, which are designed to be connected here. The purpose of the rotating flux element 12 is to change the inductances L1-4 of the respective resting coils 6a-d (which is under the A1 or A2 part or section of the flux element 12) under the influence of eddy currents / to reduce that form in the metallic flux element 12. The contour of the A2 section of the flux element 12 is identical to the contour of the even-numbered (L2 and L4) inner tra pezoidal planar coils 6b, d (coil type 24b). Similarly, the contour of the A1 portion of the flux element 12 is identical to the contour of the odd-numbered (L1 and L3) outer trapezoidal planar coils 6a, c (coil type 24a). The respective sections A1 and A2 and the associated coils 6a, c and 6b, d are therefore each congruent. The arc lengths B1, 2 of A1 section and A2 section of the flow element 12 are dimensioned such that the A1 section completely covers, for example, one quadrant of the disk, for example on the left side of the circular disk 22, and the A2 section another quadrant , for example on the right side of the circular disk 22, covers completely dig. Therefore, the entire arc length (angular extent W) of the flow element 12 (A1 and A2 sections together) covers two adjacent quadrants or a semicircle of the circular disk 22. The connecting line (or center in the circumferential direction) of the A1 and A2 sections of the flow element 12 serves as a pointer for the angular position measurement (see Figure 3).

FIG. 3 shows the fully assembled sensor arrangement 2 with components from FIGS. 1 and 2.

In FIG. 3a, the thin / laminar Cu activator in the form of the flux element 12 is positioned in such a way that it completely covers the L1 coil 6a. This position is considered to be the 0 ° position of the angle of rotation D, since the connecting line between sections A1 and A2 of the flux element 12 is aligned with the 0 ° position of the angle of rotation D. The flux element 12 is located or now rotates above the coils 6a-d and thereby maintains the fixed spacing gap a.

Section A1 is located entirely in quadrant Q1 and therefore covers coil 6a (L1). The section A2 is located in quadrant Q4 above the circular disk 22 and does not cover any of the coils 6a-d. Therefore, only the L1 coil 6a is influenced by the A1 section of the Cu activator and its inductance value L1 is reduced to the lowest value Llow (nH). The coils 6b-d (L2, L3 and L4) are, however, not subject to any influence of a part of the flux element 12 and show their respective maximum inductance values L2,3,4 of (or in the vicinity of approximately) Lhigh (nH).

If the activator rotates clockwise by 45 °, for example (not shown intermediate position between the positions from Figures 3a, b), the sections A1 and A2 of the flux element 12 partially cover both coils 6a and 6b (L1 and L2), whereby both coils generate an intermediate inductance value L1, 2 between Llow and Lhigh. According to FIG. 3b, the flux element 12 completely covers the L2 coil 6b. This is considered to be the 90 ° position of the angle of rotation D because the line connecting A1 and A2 is now aligned with the 90 ° position. Section A1 is now located in quadrant Q2 above circular disk 22 and does not cover any coils 6a-d, from section A2 is located in quadrant Q1 above coil 6b (L2). Only the L2 coil 6b is therefore influenced by the A2 section of the flux element 12.

According to FIG. 3c, the flux element 12 lies completely above the L3 coil 6c; this is considered to be the 180 ° angular position of the angle of rotation D. Section A1 is located in quadrant Q3 and covers coil 6C (L3), section A2 is located in quadrant Q2. The coil L3 is influenced under the A1 section of the flux element 12.

According to FIG. 3d, the flux element 12 is positioned such that it completely covers the L4 coil 6d. This corresponds to the 270 ° angular position of the angle of rotation D. In this case, section A1 is located in quadrant Q4 and section A2 is located in quadrant Q3 (coil 6d, L4). The L4 coil 6d is under the influence of the section A2 of the flux element 12.

In Figure 4, the course of the inductances L1-4 is shown when - depending on the angle of rotation D - the flux element partially or completely covers the coils 6a-d. The coil inductances L1-4 change over the angle of rotation D according to the curves presented. The respective inductance value L1-4 is converted into a suitable electrical signal (mV), and then a microcontroller / ASIC (in the evaluation device 18, not shown) is used to estimate or estimate the center position of the flux element 12 (angle of rotation D) . to determine. The flux element 12 is fixedly attached to a rotating (non-metallic, not shown) disk. The latter is also rigidly attached to a rotating shaft of the Ro sector of an electrical machine, not shown. The part of the sensor arrangement 2 from FIG. 1, on the other hand, is fixed in a stationary manner with respect to the stator of the machine. The angle of rotation D of the sensor arrangement 2 therefore indicates the angle of rotation D of the rotor to the stator. The assignment of quadrants Q1-4 to the angles of rotation is in Figure 4 entered. Arrow 32 indicates the clockwise rotation of the flux element 12.

Figure 5 shows an alternative embodiment of a sensor arrangement 2 namely a Radial Type Inductive Rotor Angular Position Measurement Sensor (Radial IRPS): Compared to Figures 1-3, a slight modification was carried out since the sensor arrangement 2 functions as a radial angular position sensor.

According to FIG. 5a (comparable to FIG. 1), instead of a non-metallic disk 22, a non-metallic cylinder or cylinder jacket 28 of a straight circular cylinder is used. Its length L or height corresponds to the difference between the radii R2-R1 of the circular disk 22 in Figure 1. The radius of the cylinder depends, for example, on the electric motor on which the sensor arrangement 2 is to be used. The two PCBs or printed circuit boards 20a, b, which carry the coils 6a-d, are arranged on the inside of the non-metallic cylinder or cylinder jacket 28 in the inner quadrants Q1 and Q3. The surface 16 is therefore a circular cylinder jacket (radial inner side).

The coil groups 4a, b here each have the shape of a quarter of the circumference of a circular cylinder jacket.

According to FIG. 5b, a further non-metallic cylinder 30 serves to attach the activator or the flux element 12 to the outer surface of the second cylinder 30. The outer radius of the cylinder 30 is such that, when it is firmly connected to the rotor shaft, it rotates inside the cylinder jacket 28, a predetermined vertical air gap (spacing gap a, in mm or) between the PCB coil 6a-d (radially inner surface) and the radially outer surface of the flux element 12 on the cylinder 30 is maintained.

For both embodiments (FIGS. 1-3 and FIG. 5), the coils 6a, b and the coils 6c, d are each perpendicular to the circular path 14 next to one another on the surface 16. Figure 6 shows simulation results for the clockwise rotating flux element 12 according to Figures 1 to 3. It should be emphasized that the coils 6a (also "T1 / L1) and 6c (also" T3 / L3 ") as" Top "- Coils and the coils 6b (also "B2 / L2") and 6d (also "B4 / L4") as "bottom" coils together form a trapezoidal coil group 4a, b and two such coil groups 4a, b are used here. Coil group 4a is placed in quadrant Q1, coil group 4b in quadrant Q3. Figure 6 shows the course of the inductances L1 to L4 over the angle of rotation D.

FIG. 7 shows in a table for which coils 6a-d (T 1, B2, T3, B4) fall (upper line 34, indicated by the down arrow) or rising (lower line 36, indicated by the up arrow) ) Inductance values (L in pH), i.e. tendencies, result. The coils 6a-d are indicated by the abovementioned designations "T" for "Top" and "B" for "Bottom" and are also entered again in the respective quadrant columns Q1 and Q3 in which they are located. The rotation of the flux element 12 takes place again in a clockwise direction (from left to right in the table). FIG. 7 thus represents a status table for the sensor arrangement 2. The angle of rotation D is shown as a rising angle (0 ° to 720 °).

It is very important to emphasize the following: For a clockwise rotation of the flux element 12 (lower line in the table, Fig. 7), the table shows the rotation (Q1 -> Q2 -> Q3 -> Q4) sequentially for the T1, B2, T3 and B4 coils 4a-d increasing inductances (values).

For the counterclockwise rotation, the lower line of the table shows that sequentially the B4, T3, B2 and T1 coils 4a-d have increasing inductances (values).

With regard to the figures, it should be noted that the quadrant sequence differs from conventional numbering (usual convention): Q1, Q3 are conventionally numbered, Q2 and Q4 are reversed.

FIGS. 8 shows, corresponding to FIGS. 1-3 an alternative sensor arrangement 2 with only one coil group 4a with two coils 6a, b and only one empty area 8a. This extends over an empty angle E1 of 180 °. The coil group 4a extends over the quadrants Q1,2 over a coil angle S1 of 180 °, which is equal to the total angle G. The arcuate thin / laminar flow element 12 (CU activator) extends over an angular extent W of 360 °, the sections A1, A2 each over arc lengths B 1, 2 of 180 °. The circular path 14 around the axis of rotation 10 is only indicated here by dashed lines. Otherwise, the Sensoran arrangement 2 is corresponding or analogous to Figs. 1-3 and is operated like this. Although the coil group 4a only covers 180 ° of the circular disk 22 here, the sensor arrangement 2 can measure the full 360 ° angle of rotation D of a rotor movement.

The coils 4a, b are located on a single printed circuit board 20a (circular ring segment) on the non-metallic circular disk 22 (circular ring).

Referring to sensor arrangement a, b coil group a-d coil a, b empty area

10 axis of rotation

12 flow element

14 circular path

16 area

18 Evaluation device

20a, b circuit board

22 circular disc

24a, b coil type

26 holes

28 cylinder jacket

30 cylinders

32 arrow

34 line (top)

36 line (bottom)

L1-4 inductors

D rotation angle

W angular expansion

S1, 2 coil angles

G total angle

E1, 2 empty angles a spacing gap

Q1-4 quadrant

A1, 2 section

B1, 2 arc length

L length

R1, 2 radius

Claims

1. Sensor arrangement (2) for detecting an angle of rotation (D) of a flux element (12) which can be rotated along a circular path (14) about an axis of rotation (10),

- With at least one coil group (4a, b) interacting with the flux element (12), each with at least two coils (6a-d),

- The coil groups (6a-d) extending in a surface (16) concentrically surrounding the axis of rotation (10),

- wherein the surface (16) runs parallel to and along the circular path (14), and a respective coil group (4a, b) along the circular path (14) is limited to a respective Spu lenwinkel (S1, 2),

- The coil angles (S1, 2) of all coil groups (4a, b) add up to a total angle (G) of less than 360 °,

- wherein at least one empty area (8a, b) is present along the circular path (14) which extends over a respective empty angle (E1, 2),

- With the flux element (12), which extends parallel with the interposition of a gap gap (a) to the surface (16),

- wherein the flux element (12) along the circular path (14) has an angular extent (W) which is greater than the largest coil angle (S1, 2),

- With an evaluation device (18) which is set up to determine the current inductance (L1-4) for each of the coils (6a-d) and a current angle of rotation (D) of the flux element (12) on the basis of at least two determined To determine inductances (L1-4).

2. Sensor arrangement according to claim 1, characterized in that at least two coil groups (4a, b) are present, and along the circular path (14) there is at least one empty area (8a, b) between each two coil groups (4a, b).

3. Sensor arrangement (2) according to one of the preceding claims, characterized in that the same number of coil groups (4a, b) and empty areas (8a, b) are arranged alternately along the circular path (14).

4. Sensor arrangement (2) according to one of claims 2 to 3, characterized in that at least two of the coil angles (S1, 2) are of the same size and / or at least two of the empty angles (E1,2) are of the same size.

5. Sensor arrangement (2) according to one of claims 2 to 4, characterized in that exactly two coil groups (4a, b) and exactly two empty areas (8a, b) are IN ANY.

6. Sensor arrangement (2) according to one of claims 1 to 5, characterized in that the total angle (G) is 180 ° and / or the angular extent (W) is 360 ° and / or at least one of the coil angles (S1, 2) is 180 ° and / or at least one of the empty angles (E1, 2) is 180 °.

7. Sensor arrangement (2) according to one of claims 2 to 5, characterized in that the total angle (G) is 180 ° and / or the angular extent (W) is 180 ° and / or at least one of the coil angles (S1, 2) is 90 ° and / or at least one of the empty angles (E1, 2) is 90 °.

8. Sensor arrangement (2) according to one of the preceding claims, characterized in that the flow element (12) is designed to be suspended along the circular path (14) or is divided into at least two adjoining or spaced apart sections (A1, 2) .

9. Sensor arrangement (2) according to one of the preceding claims, characterized in that the angular extent (W) is at least as large as the largest sum of a coil angle (S1, 2) and an adjacent empty angle (E1, 2).

10. Sensor arrangement (2) according to one of claims 2 to 9, characterized in that at least one type of coil (24a, b) is present for the same coils (6a-d) and at least two coil groups (4a, b) are each one of the same Hold coils (6a-d) ent, which are arranged rotationally symmetrical to the axis of rotation (10).

11. Sensor arrangement (2) according to claim 10, characterized in that at least one coil type (24a, b) is assigned a respective section (A1, 2) of the flux element (12).

12. Sensor arrangement (2) according to claim 11, characterized in that at least one of the sections (A1, 2) is congruent with the associated coil type (24a, b).

13. Sensor arrangement (2) according to one of the preceding claims, characterized in that in at least one of the coil groups (4a, b) at least two of the coils (6a-d) in the surface (16) perpendicular to the circular path (14) lie side by side gene.

14. Sensor arrangement (2) according to one of the preceding claims, characterized in that at least one of the coils (6a-d) has a shape tapering along the circular path (14).

15. Sensor arrangement (2) according to one of the preceding claims, characterized in that at least one of the coil groups (4a, b) has the shape of a circular segment or a peripheral portion of a circular cylinder jacket.

16. Sensor arrangement (2) according to one of the preceding claims, characterized in that the surface (16) has the shape of a disc transverse to the axis of rotation (10) or a jacket of a straight truncated circular cone or a jacket of a straight circular cylinder with respect to the axis of rotation (10 ) having.