Scanning element for inductive position measuring device

Abstract

The invention relates to a scanning element for an inductive position measuring device, comprising a multi-layer printed circuit board (1) having a first receiver rail (1.1) extending in a first direction (x) and an exciter rail (1.3). The first receiver rail (1.1) is formed by a plurality of first rail segments (1.111) connected in series. In the structure of the printed circuit board (1), the two first guide rail segments (1.111) are arranged offset from one another and parallel with respect to the third direction (z) along the partial path (A). A further one of the first guide rail segments (1.111) extends in the structure of the printed circuit board (1) along a first sub-segment (B1) arranged offset in the first direction (x) with respect to the sub-path (A), while the first guide rail segment (1.111) does not extend parallel with respect to the further one of the first guide rail segments (1.111) with respect to the third direction (z).

Description

Technical Field

[0001] The invention relates to a scanning element for an inductive position-measuring device for determining the position of the scanning element relative to a scale element.

[0002] Inductive position measuring devices are used, for example, as angle measuring devices to determine the angular position of machine parts that can rotate relative to one another, or as length measuring devices to determine the position due to a linear displacement. In inductive position measuring devices, the exciter track and the receiver track are usually applied, for example in the form of guides, on a common, usually multilayer printed circuit board, which is, for example, fixedly connected to the stator of the angle measuring device. In particular, in an embodiment of a scanning element with a printed circuit board, the exciter track and the receiver track can be formed by an exciter rail and a receiver rail. Opposite the printed circuit board is located a scale element, on which a graduation structure is applied and which is connected to the rotor of the position measuring device. If a time-varying electrical excitation current is applied to the exciter rail, a signal that depends on the relative position is generated in the receiver rail during the relative movement between the rotor and the stator. These signals are then further processed in the evaluation electronics. Background Art

[0003] EP 4 170 289 A1 discloses an inductive position measuring device having a receiver track interrupted by a gap. This type of construction contributes to reducing the sensitivity to pitch tilt. Summary of the invention

[0004] The invention is based on the object of creating a scanning element for an inductive position-measuring device which operates relatively accurately in terms of electrical energy, can be produced compactly and cost-effectively and is insensitive to pitch tilt.

[0005] According to the invention, this object is achieved by the features of claim 1 .

[0006] A scanning element suitable for and intended for an inductive position measuring device comprises a multilayer printed circuit board having a first receiver track extending in a first direction. In addition, the printed circuit board has an exciter track. The first receiver track comprises a plurality of first loops, wherein the first loops are formed by a plurality of first track segments. The first track segments extend in different layers of the printed circuit board and are connected in series with each other, in particular through vias, and thus form an electrically universal track. In the structure of the printed circuit board along a sub-path, two first track segments are arranged in parallel and staggered with respect to a third direction (or in the third direction). The third direction is oriented orthogonal to the first direction. In particular, two loops extend in parallel in the sub-path staggered in the third direction and staggered with each other in different layers of the printed circuit board in the third direction, wherein the loops consist of first track segments. Another track segment in the first track segment extends in the structure of the printed circuit board along a first sub-segment arranged staggered relative to the sub-path in the first direction. However, in the sub-segment, no printed circuit segment is arranged in parallel with respect to another first track segment and staggered in the third direction. Therefore, another of the first guide rail segments extends in the structure of the printed circuit board without the first guide rail segments extending offset with respect to the third direction and parallel to the other first guide rail segments.

[0007] The first direction represents the direction of the position sought for measurement (measurement direction). Since, according to an embodiment, the relative angular position between the scale element and the scanning element is to be measured by a position measuring device with a scanning element, the first direction in this case is a circumferential direction or a tangential direction. Alternatively, if a relative displacement is measured, the first direction can also be a linear direction.

[0008] Furthermore, a second direction extending orthogonally with respect to the first direction can be defined.

[0009] The third direction is oriented orthogonally to the first direction and at the same time orthogonally to the second direction. The third direction is oriented orthogonally to the plane of the printed circuit board. In addition, the individual layers of the printed circuit board are arranged offset relative to one another in the third direction. In the case of angular position measurement, the third direction extends parallel to the (rotational) axis about which the scale element can be rotated relative to the scanning element.

[0010] Thus, the scanning element can scan a linear scale or a curved scale element, in particular a circular or circular segment-shaped scale element, so that a linear position or an angular position can be measured. Thus, the first receiver track can extend along a first direction on a linear path or a curved path. The path comprises sub-segments, namely a sub-path and a first sub-segment.

[0011] Parallel guide rail segments are guide rail segments that extend in principle in the same direction, in particular in the form of parallel curves or in particular parallel to one another in a geometric sense. In particular, two first guide rail segments along a subpath in the structure of the printed circuit board can be arranged one above the other with reference to the third direction, or at least their starting point and their end point can overlap one another. The starting point and the end point can be designed as vias.

[0012] Signals having the same phase are received or generated by the parallel track sections, so that the signal level is increased by connecting the parallel track sections in series.

[0013] Advantageously, the first rail section of the first receiver rail extends over exactly four layers of the printed circuit board.

[0014] When measuring the angular position, as described above, the scale element and the scanning element are arranged to be rotatable relative to each other about the axis. In particular, for measuring the angular position, it is advantageous if, when the first receiver rail extends in a first direction along an arc segment at a first center angle, the first center angle is less than 180°, in particular less than 135°, advantageously less than 90°. The center angle is the central angle of a circle around a point on the axis.

[0015] In another embodiment of the present invention, two first guide rail segments are arranged exactly in parallel along the sub-path and are arranged offset from each other with reference to a third direction. Conversely, only exactly one other first guide rail segment extends along the first sub-segment without the first guide rail segment extending in parallel with respect to the other first guide rail segment with reference to the third direction.

[0016] Advantageously, the first receiver track has a periodic course along the first direction with a period length, wherein the first sub-segment extends in the first direction over a length that is at least as long as half the period length. The period length can be understood as a measure of an angle or arc for an angular position, so that the period length can be specified, for example, in degrees. Accordingly, the length over which the sub-segment extends in the first direction can also be specified as an angle.

[0017] The sub-path is advantageously arranged offset with respect to the first sub-section in the first direction.

[0018] Advantageously, the multilayer printed circuit board further comprises a second receiver track, which extends along a first direction on a straight path or a curved path and is arranged offset relative to the first receiver track in the first direction. The second receiver track in turn comprises a plurality of second loops, which are formed by a plurality of second track segments. The second track segments are connected in series and thus form an electrical universal track. In the structure of the printed circuit board, two second track segments are arranged in parallel along the sub-path and are arranged offset relative to each other with reference to a third direction. Another second track segment of the second track segment extends along a second sub-segment arranged offset relative to the sub-path in the first direction, without the second track segment extending in parallel with respect to the other second track segment offset relative to the third direction.

[0019] The first receiver rail and the second receiver rail are located on the same receiver track. Like the first receiver rail, the second receiver rail can extend along a straight path or a curved path in a first direction. The path includes sub-segments, namely a sub-path and a first sub-segment.

[0020] Advantageously, the first receiver track and the second receiver track each have a periodic course along the first direction with a correspondingly identical period length.

[0021] In another embodiment of the present invention, the first subsection is arranged offset relative to the second subsection in a first direction, so that the first subsection and the second subsection do not overlap.

[0022] Advantageously, the first rail section of the first receiver rail and the second rail section of the second receiver rail, ie both receiver rails together, extend over exactly four layers in the structure of the printed circuit board.

[0023] Advantageously, the second receiver rail extends in the first direction along an arc segment at a second center angle that is less than 180°, in particular less than 135°, advantageously less than 90°. The second receiver rail can extend in the first direction along an arc segment at a center angle that is similarly large as the first receiver rail, wherein the first receiver rail is arranged offset relative to the second receiver rail in the first direction.

[0024] In a further embodiment of the invention, exactly two second rail sections are arranged in parallel and offset relative to one another along the sub-path in the structure of the printed circuit board with reference to the third direction. In the structure of the printed circuit board, exactly one second rail section extends along the second sub-section without any other second rail section extending offset relative to the third direction and parallel to the first rail section.

[0025] Preferably, the exciter rail surrounds the first receiver rail and the second receiver rail.

[0026] Advantageously, the second receiver track has a periodic course along the first direction with a periodic length, wherein the second partial section extends in the first direction over a length which is at least as long as half the periodic length.

[0027] Advantageously, the first receiver track and the second receiver track each have a periodic course with a periodic length in the first direction, wherein the first subsection extends over a length in the first direction and the second subsection extends over a length of the same magnitude.

[0028] Advantageous embodiments of the invention can be gathered from the dependent claims.

[0029] Further details and advantages of the scanning element according to the invention emerge from the following description of exemplary embodiments with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A top view of the scanning element is shown, Figure 2 A detailed cross-sectional view showing the scanning element, Figure 3 A top view of the scale element is shown, Figure 4 Detail view showing scale elements, Figure 5A a shows a detail view of a first track segment of a first layer of a printed circuit board of a scanning element, Figure 5A b shows a detail view of the first track segment of the second layer of the printed circuit board of the scanning element, Figure 5A c shows a detail view of the first rail segment of the third layer of the printed circuit board of the scanning element, Figure 5A d shows a detail view of the first track segment of the fourth layer of the printed circuit board of the scanning element, Figure 5B A detailed view of the first rail section of all four layers of the printed circuit board showing the scanning element, Fig. 6A a shows a detail view of the second rail segment of the first layer of the printed circuit board of the scanning element, Fig. 6A b shows a detail view of the second rail segment of the second layer of the printed circuit board of the scanning element, Fig. 6A c shows a detail view of the second rail segment of the third layer of the printed circuit board of the scanning element, Fig. 6A d shows a detail view of the second track segment of the fourth layer of the printed circuit board of the scanning element, Figure 6BA detailed view of the second rail section of all four layers of the printed circuit board showing the scanning element, Figure 7 A detail view of the first receiver rail and the second receiver rail is shown. DETAILED DESCRIPTION

[0031] according to Figure 1 The invention is described using a position measuring device having a scanning element comprising a printed circuit board 1 .

[0032] The scanning element can be used to detect the angular position of the scale element 2. Figure 3 is shown in a top view of . The scale element 2 has a disc-shaped or annular shape and is arranged to be rotatable relative to the printed circuit board 1 around an axis R. The scale element consists of a substrate, which in the embodiment shown is made of epoxy resin and on which three scale tracks 2.1, 2.2, 2.3 are arranged. The scale tracks 2.1, 2.2, 2.3 are designed as annular and are concentrically arranged on the substrate with different diameters based on the axis R. The scale tracks 2.1, 2.2, 2.3 include a scale structure, which consists of a periodic sequence of alternating conductive scale areas 2.11, 2.21, 2.31 and non-conductive scale areas 2.12, 2.22, 2.32, respectively ( Figure 4 ). In the example shown, copper is applied to the substrate as material for the conductive graduation areas 2.11, 2.21, 2.31. In contrast, the substrate is not coated in the non-conductive graduation areas 2.12, 2.22, 2.32. Alternatively, the graduation element can also be designed so that it has a steel substrate coated with an insulating layer, on which graduation areas, for example made of copper, are applied.

[0033] The arrangement with three graduated tracks 2.1, 2.2, 2.3 makes it possible to absolutely determine the angular position of the graduated element 2. The middle graduated track 2.1 of the graduated element 2 has the largest number (here 182 pairs) of graduated areas 2.11, 2.12 along the circumference, so that the maximum resolution for the measurement of the angular position can be achieved through it. The inner graduated track 2.3 has the smallest number of graduated areas 2.31, 2.32 along the circumference, which in the embodiment presented are 168 conductive graduated areas 2.31 and 168 non-conductive graduated areas 2.32 respectively. Finally, the outer graduated track 2.2 has an intermediate number (here 169 pairs) of graduated areas 2.21, 2.22, which is less than the number of the middle graduated track 2.1.

[0034] Figure 1 A top view of a printed circuit board 1 is shown. This comprises three receiver tracks D, E, F which extend along a first direction x, which can also be referred to as a measuring direction, and which extend in a circumferential direction around an axis R.

[0035] Figure 2 A schematic partial cross-sectional view of a printed circuit board 1 is shown, wherein, in order to better explain the scanning element 1 according to the present invention, Figure 2 The partial cross-sectional views are not drawn to scale. As described above, the printed circuit board 1 is constructed as a multilayer and therefore comprises a first conductive layer L1, a second conductive layer L2, a third conductive layer L3 and a fourth conductive layer L4. In addition, the printed circuit board 1 has electronic components (not shown in the figure) mounted on the printed circuit board 1. The geometric relationship of the individual elements to each other can be defined using a coordinate system. The first direction x is the direction along which position measurements or angle measurements should conventionally be made. In the embodiment presented, the first direction x corresponds to the circumferential direction. The scale element 2 can rotate around an axis R, which extends parallel to the third direction z, so that the third direction z can also be defined here as an axial direction. The second direction y is oriented orthogonal to the third direction z and the first direction x, and it can also be referred to as a radial direction. Therefore, according to Figure 2 , the conductive layers L1 to L4 are arranged offset from each other in the third direction z.

[0036] The receiver tracks D, E, F extend in each of the four conductive layers L1 to L4 in a strip with a defined radial extent. The conductive layers L1 to L4 are designed such that (according to Figure 1 ) forms a first receiver rail 1.1 and a second receiver rail 1.2. The two receiver rails 1.1, 1.2 are arranged offset from each other along a first direction x (circumferential direction) so that they can provide two phase-shifted signals according to the offset. The receiver rails 1.1, 1.2 are designed as ring segments and extend in a first direction x (measuring direction). Therefore, the scale element 2 is scanned only along the circumferential segment and not simultaneously over the entire circumference as in the usual prior art. In the presented embodiment, the first receiver rail 1.1 extends along an arc segment in the first direction x at a first center angle α1 of approximately 25°. The second receiver rail 1.2 also extends along an arc segment in the first direction x at a second center angle α2 that is slightly different from α1. For the examples of all three receiver rails D, E, F, their structure is explained using the radially centered first receiver rail D.

[0037] according to Figure 5B , the first receiver rail 1.1 comprises a plurality of first loops 1.11, wherein the first loops 1.11 are formed by a plurality of first rail segments 1.111, which are connected in series. In addition, the first rail segments 1.111 connected to the vias extend in different layers L1 to L4 to avoid undesired short circuits. Although, to be precise, the first receiver rail 1.1 is composed of a plurality of rail segments 1.111, each of which is distributed and arranged on different layers L1 to L4, such a structure is collectively referred to as the receiver rail 1.1 hereinafter.

[0038] exist Figure 5A a to Figure 5A In d, the course of the first guide rail segments 1.111 in the four layers L1 to L4 is shown individually and in sub-areas with respect to a first direction x, wherein for the sake of clarity not every first guide rail segment 1.111 is provided with a reference numeral. Here, the layer L1 is the top layer, and below (staggered in the z direction) are the second, third and fourth layers L2 to L4, wherein the fourth layer L4 is then shown as the bottom layer. Figure 5B A top view of a printed circuit board 1 is shown, in which all four layers L1 to L4 are visible, with the first layer L1 being the topmost layer. The first rail section 1.111 preferably has through-holes or vias at the ends of the first rail section, respectively, leading to the layers L1 to L4 located above or below. Figure 5A a to Figure 5A In d, for the sake of explanation, the contacts or interconnections of the individual first rail segments 1.111 are shown by dashed lines. Figure 5A a to Figure 5A In d, arrows are introduced, which are intended to indicate which first guide rail segments 1.111 are arranged offset to one another and in parallel with respect to the third direction z, in particular in parallel. Figure 5A a to Figure 5A The first guide rail segments 1.111 indicated by the arrows arranged one above the other with the same hatching in d are arranged one above the other in the structure of the printed circuit board 1. For example, the first guide rail segment 1.111 pointed to by the vertical hatched arrow with the reference numeral p1 is offset relative to the first guide rail segment 1.111 pointed to by the vertical hatched arrow with the reference numeral p1 with respect to the third direction z. Figure 5A b and Figure 5A As can be seen from the figure c, the first guide rail segments 1.111 in question also extend in parallel in the layers L2 and L3, in particular parallel to each other. This parallel arrangement of the first guide rail segments 1.111 in the different layers L1 to L4 is interrupted in the first subsection B1. In this first subsection B1, a connection is made from the fourth layer L4 to the first layer L1 for the purpose of connecting the individual first guide rail segments 1.111 in series. In this context, Figure 5AThe first guide rail segment 1.111 pointed to by an arrow with reference symbol r1 in d is first electrically connected to a short first guide rail segment 1.111 in the third layer L3. The short first guide rail segment 1.111 in the third layer L3 is connected here to a short first guide rail segment 1.111 in the second layer L2. At the other end of the short first guide rail segment 1.111 in the second layer L2, contact is made with the first guide rail segment 1.111 in the first layer L1, to which the arrow with reference symbol s1 points. In this way, the first guide rail segment 1.111 in the fourth layer L4 is electrically connected in stages to the first guide rail segment 1.111 in the first layer L1. In addition, the design of the first sub-segment B1 described here creates space for a second receiver rail 1.2, which is formed by a second guide rail segment 1.211, wherein the second guide rail segment 1.211 is not in Figure 5A a to Figure 5A d, but likewise extends in four layers L1 to L4, and the first guideway segments 1.111 traverse the layers L1 to L4 at different positions in a manner electrically insulated from one another.

[0039] Figure 5B A partial cross section of the first receiver rail 1.1 is shown, wherein according to Figure 5A a to Figure 5A d can be recognized that a loop 1.11 is formed by the individual first guide rail segments 1.111. Along the sub-path A, at least two first guide rail segments 1.111 are arranged offset with respect to the third direction z and in parallel, in particular in parallel, in the structure of the printed circuit board 1. In other words, in the sub-path A, the loop 1.11 extends in parallel, in particular in parallel, one above the other in the structure of the printed circuit board 1. In contrast, at least one of the first guide rail segments 1.111 extends along the first sub-segment B1 in the structure of the printed circuit board 1 without the other first guide rail segments 1.111 extending offset with respect to the third direction z and extending in parallel, in particular in parallel, relative to one of the first guide rail segments 1.111. In the first sub-segment B1, the loop 1.11 simply extends without the presence of other loops 1.11 that are offset in the third direction, in particular in parallel.

[0040] exist Fig. 6A a to Fig. 6A d shows the course of the second guide rail section 1.211 in the four layers L1 to L4, similar to Figure 5A a to Figure 5A The representation of d. Figure 6B A plan view of a printed circuit board 1 is shown, wherein all four layers L1 to L4 are visible, with the first layer L1 being the uppermost layer.

[0041] The second guide rail segments 1.211 also each have a through hole toward the layer L1 to L4 located above or below. Fig. 6A a to Fig. 6A In d, the contacts or interconnections of the individual second rail segments 1.211 are shown by dashed lines in order to explain the connections or interconnections. Fig. 6A a to Fig. 6A In d, an arrow is also introduced, which is intended to explain which second guide rail segments 1.211 are arranged offset to one another and in parallel with respect to the third direction z, in particular in parallel. Fig. 6A a to Fig. 6A The second guide rail segments 1.211 indicated by arrows with the same shading arranged one above the other in d are arranged one above the other in the structure of the printed circuit board 1. Accordingly, the second guide rail segment 1.211 pointed to by the vertically shaded arrow with the reference numeral p2 is offset relative to the second guide rail segment 1.211 pointed to by the vertically shaded arrow with the reference numeral q2 with reference to the third direction z. Fig. 6A b and Fig. 6A As can be seen from the figure c, the second guide rail segments 1.211 in question also extend in parallel in the layers L2 and L3, in particular parallel to each other. This parallel arrangement of the second guide rail segments 1.211 in the different layers L1 to L4 is interrupted in the second subsection B2. In this second subsection B2, a connection is made from the fourth layer L4 to the first layer L1 for the purpose of connecting the individual second guide rail segments 1.211 in series. In this context, Fig. 6A The second guide rail segment 1.211 pointed to by the arrow with the reference numeral r2 in d is first electrically connected to the short second guide rail segment 1.211 in the third layer L3. This short second guide rail segment 1.211 in the third layer L3 is again connected to the short second guide rail segment 1.211 in the second layer L2. At the other end of the short second guide rail segment 1.211 in the second layer L2, contact is made with the second guide rail segment 1.211 in the first layer L1, to which the arrow with the reference numeral s2 points. In this way, the second guide rail segment 1.211 in the fourth layer L4 is electrically connected in stages to the second guide rail segment 1.211 in the first layer L1. In addition, the design of the second sub-segment B2 described here creates space for the first receiver rail 1.1, which is formed by the first guide rail segment 1.111, wherein the first guide rail segment 1.111 is Fig. 6A a to Fig. 6A d, but likewise extends in four levels L1 to L4 and second guideway segments 1.211 traverse them in different locations L1 to L4 in a manner electrically insulated from one another.

[0042] exist Figure 6B A partial cross section of the second receiver rail 1.2 is shown, wherein the loop 1.21 is arranged according to Fig. 6Afrom a to Fig. 6A The d of is recognizably formed by respective second guide rail segments 1.211. Along the sub-path A, in the structure of the printed circuit board 1, at least two second guide rail segments 1.211 are arranged offset from each other and in parallel with respect to the third direction z, in particular parallelly arranged. In other words, in the sub-path A, the loops 1.21 extend one above the other in parallel, in particular parallelly, in the structure of the printed circuit board 1. In contrast, along the second sub-segment B2, at least one of the second guide rail segments 1.211 extends in the structure of the printed circuit board 1 without offsetting another second guide rail segment 1.211 with respect to the third direction z and extends parallelly, in particular parallelly, with respect to one of the second guide rail segments 1.211. In the second sub-segment B2, the loop 1.21 simply extends without the presence of another parallel loop 1.21 offset in the third direction.

[0043] The receiver guide rails 1.1, 1.2 or the associated loops 1.11, 1.21 have a spatially periodic course that is substantially sinusoidal or sinusoid-like. The first receiver guide rails 1.1 and 1.2 of the receiver track D have a first period length l1. The receiver guide rails 1.4, 1.5 of the receiver track E each have a second period length l2, and the receiver guide rails 1.6, 1.7 of the receiver track F each have a third period length l3. In the presented embodiment, the first period length l1 is less than the second period length l2 and the second period length l2 is less than the third period length l3 (l1 < l2 < l3), where the period lengths l1, l2, l3 are here stated as angular measures in degrees.

[0044] In the presented embodiment, the first receiver guide rails 1.1 and 1.2 are arranged within the receiver track D or offset in the first direction such that they provide a 0° signal and a 90° signal. The same considerations also apply to the receiver tracks E, F, and the receiver guide rails 1.4, 1.5, 1.6, 1.7 of the receiver tracks also provide a 0° signal and a 90° signal.

[0045] The first receiver track D provides a position signal with a higher resolution than the other two receiver tracks E, F, in particular because the first period length l1 is less than the second period length l2.

[0046] In Figure 7In the figure, the first receiver track 1.1 and the second receiver track 1.2 or the loops 1.11, 1.21 formed therefrom are shown one above the other, as is the case in the structure of the printed circuit board 1. In the first subsection B1, there are vias, via which the first track segment 1.111 in the fourth layer L4 is electrically connected in stages to the first track segment 1.111 in the first layer L1. Similarly, in the second subsection B2, there is a second track segment 1.211, which is also electrically connected in stages to the second track segment 1.211 in the first layer L1 via vias. Figure 7 Vias can also be seen at the edges of the first subsection B1 and the second subsection B2. It can be said that these form the reversal points of the loops 1.11, 1.21, so that in subpath A, the loops 1.11, 1.21 are executed twice in the structure of the printed circuit board 1, offset from each other in the third direction and parallel on different layers L1 to L4. In contrast, the loop 1.11 in the first subsection B1 and the loop 1.21 in the second subsection B2 are formed only once. Although the four rails of the receiver rails 1.1, 1.2 run within the period length l1, due to the serial connection and the reversal points, only two phases are scanned or two signals (0° signal, 90° signal) are generated.

[0047] Furthermore, the printed circuit board 1 comprises an actuator track 1.3, which here has two actuator rails. The actuator track 1.3 surrounds the first receiver track 1.1 and the second receiver track 1.2.

[0048] In the assembled state, the printed circuit board 1 and the scale element 2 face each other with an axial distance or air gap, so that in the case of relative rotation between the scale element 2 and the printed circuit board 1, signals that depend on the corresponding angular position can be generated in the receiver tracks D, E, F, in particular also in the receiver guides 1.1, 1.2 by inductive effect. The prerequisite for the formation of the corresponding signals is that the excitation guides of the excitation track 1.3 generate a time-varying electromagnetic excitation field in the area of ​​the respective scanning graduation structure. In the embodiment shown, the excitation guides are designed as a plurality of plane-parallel flow-through individual guides. The scanning element has an electronic circuit with electronic components on the printed circuit board 1, which are electrically connected to each other via other layers of the printed circuit board 1 not shown in the figure.

[0049] If the exciter rail 1.3 is excited in the corresponding current direction, an electromagnetic field oriented in a tubular or cylindrical shape is formed around the exciter rail. The field lines of the generated electromagnetic field extend around the exciter rail 1.3, wherein the direction of the field lines depends on the direction of the current in the exciter rail in a known manner. Eddy currents are induced in the region of the conductive graduation areas 2.11, 2.21, 2.31, so that a corresponding field modulation depending on the angular position is achieved.

[0050] Thus, the respective relative angular position can be measured by the receiver tracks 1.1, 1.2. The receiver tracks 1.1, 1.2 are arranged such that the receiver tracks provide signals which are 90° out of phase, so that a determination of the direction of rotation can also be performed. The signals generated by the receiver tracks 1.1, 1.2 are further processed with the help of some electronic components forming an evaluation circuit. When scanning the middle graduation track 2.1 of the scale element 2, the signal of the first receiver track D provides the greatest or finest resolution of the angular position.

[0051] Especially in the case of segmented scanning, such as is present here, in which the first receiver track 1.1 extends along an arc segment in the first direction x, it is advantageous if the relative pitching movement (i.e. torsional movement) between the printed circuit board 1 and the scale element 2 is oriented about a pitch axis which is perpendicular to the first direction x (here radial), without causing any significant measuring errors when determining the angular position. Such errors caused by the pitching movement can be compensated to a large extent by the printed circuit board 1 proposed here or by the scanning element proposed here. In addition, a very high signal strength can be achieved by the arrangement of the receiver tracks 1.1, 1.2.

Claims

1. A scanning element for an inductive position measuring device, the scanning element comprising a multilayer printed circuit board (1), the multilayer printed circuit board having a first receiver track (1.1) extending in a first direction (x) and an actuator track (1.3), wherein: The first receiver rail (1.1) is formed by a plurality of first rail segments (1.111) connected in series, wherein: Two first guide rail sections (1.111) are arranged in parallel and offset from one another along a subpath (A) in the structure of the printed circuit board (1) with reference to a third direction (z), wherein the third direction (z) is oriented orthogonally to the first direction (x), and Another of the first guide rail segments (1.111) extends in the structure of the printed circuit board (1) along a first sub-segment (B1) which is arranged offset relative to the sub-path (A) in the first direction (x), without the first guide rail segment (1.111) being arranged parallel to the other first guide rail segment (1.111) and offset relative to the third direction (z).

2. The scanning element according to claim 1, wherein: The first guide rail section (1.111) of the first receiver guide rail (1.1) extends exactly on four layers (L1, L2, L3, L4) of the printed circuit board (1).

3. A scanning element according to any one of the preceding claims, wherein: The first receiver rail (1.1) extends in the first direction (x) along an arc segment having a first center angle (α1) that is less than 180°.

4. A scanning element according to any one of the preceding claims, wherein: Exactly two first guide rail segments (1.111) are arranged in parallel and offset from one another along the sub-path (A) with reference to the third direction (z) in the structure of the printed circuit board (1), and exactly one further first guide rail segment (1.111) extends along the first sub-segment (B1) in the structure of the printed circuit board (1).

5. A scanning element according to any one of the preceding claims, wherein: The first receiver track (1.1) has a periodic course with a period length (λ1) along the first direction (x), wherein the length of the first subsection (B1) extending in the first direction (x) is at least as great as half of the period length (λ1).

6. A scanning element according to any one of the preceding claims, wherein: The sub-path (A) is arranged offset relative to the first sub-section (B1) in the first direction (x).

7. A scanning element according to any one of the preceding claims, wherein: The multilayer printed circuit board (1) comprises a second receiver track (1.2) extending along the first direction (x), wherein: The second receiver rail (1.2) is formed by a plurality of second rail segments (1.211) connected in series, wherein: Two second guide rail sections (1.211) are arranged in parallel and offset from one another along the sub-path (A) with reference to the third direction (z) in the structure of the printed circuit board (1), and A further second guide rail segment of the second guide rail segment (1.211) extends in the structure of the printed circuit board (1) along a second sub-segment (B2) which is arranged offset relative to the sub-path (A) in the first direction (x), without the second guide rail segment (1.211) being arranged parallel to the further second guide rail segment (1.211) and offset relative to the third direction (z).

8. The scanning element according to claim 7, wherein: The first receiver track (1.1) and the second receiver track (1.2) each have a periodic course with the same period length (λ1) along the first direction (x).

9. The scanning element according to claim 7 or 8, wherein: The first subsection (B1) is arranged offset relative to the second subsection (B2) in the first direction (x).

10. The scanning element according to any one of claims 7, 8 or 9, wherein: The first guide rail section (1.111) of the first receiver guide rail (1.1) and the second guide rail section (1.211) of the second receiver guide rail (1.2) extend exactly on four layers (L1, L2, L3, L4) of the printed circuit board (1).

11. The scanning element according to any one of claims 7 to 10, wherein: The second receiver rail (1.2) extends in the first direction (x) along an arc segment having a second center angle (α2) that is less than 180°.

12. The scanning element according to any one of claims 7 to 11, wherein: The first receiver rail (1.1) extends in the first direction (x) along an arc segment having a first center angle (α1) smaller than 180°, wherein the second receiver rail (1.2) extends in the first direction (x) along an arc segment having a second center angle (α2) smaller than 180°, wherein the first receiver rail (1.1) is arranged offset relative to the second receiver rail (1.2) in the first direction (x).

13. The scanning element according to any one of claims 7 to 12, wherein: Exactly two second guide rail segments (1.211) are arranged in parallel and offset from one another along the sub-path (A) with reference to the third direction (z) in the structure of the printed circuit board (1), and exactly one second guide rail segment (1.211) extends along the second sub-segment (B2) in the structure of the printed circuit board (1).

14. The scanning element according to any one of claims 7 to 13, wherein: The second receiver track (1.2) has a periodic course with a period length (λ1) along the first direction (x), wherein the length of the second subsection (B2) extending in the first direction (x) is at least as great as half of the period length (λ1).

15. The scanning element according to any one of claims 7 to 14, wherein: The first receiver track (1.1) and the second receiver track (1.2) each have a periodic course with a period length (λ1) along the first direction (x), wherein in the first direction (x), the first subsection (B1) extends over the same length as the second subsection (B2).

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