Scan element for inductive position measurement mechanism

Abstract

SOLUTION: The invention relates to a scan element for an inductive position measurement mechanism which includes a multilayer printed circuit board (1) which has a first reception conductive path (1.1) and an excitation track (1.3) extending along a first direction (x). The first reception conductive path (1.1) is formed of multiple first conductive path fragments (1.111) which are connected in series. Along a subsection (A), two first conductive path fragments (1.111) are arranged in a structure of the printed circuit board (1), offset to each other with respect to a third direction (z) and arranged similarly. Along a first subsection (B1) offset to the subsection (A) in the first direction (x), a further one of the first conductive path fragment (1.111) extends in the structure of the printed circuit board (1), without one first conductor path fragment (1.111) extending similarly offset to the further first conductor path fragment (1.111) with respect to the third direction (z) (Fig. 5e).SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The invention relates to a scanning element for an inductive position measuring mechanism according to claim 1 for determining the position of the scanning element relative to a scale element. [Background technology]

[0002] Inductive position measuring devices are used, for example, as angle measuring devices for determining the angular position of machine parts that can rotate relative to one another or as length measuring devices for determining the position by linear displacement. In inductive position measuring devices, the excitation track and the receiving track are often provided, for example in the form of conductor tracks, on a common, usually multi-layer, printed circuit board, which is fixedly connected, for example, to the stator of the angle measuring device. In particular, in one embodiment of a scanning element with a printed circuit board, the excitation track and the receiving track can be formed from an excitation conductor track and a receiving conductor track. Opposite this printed circuit board, a scale element is present, on which a graduation structure is provided and which is connected to the rotor of the position measuring device. If a time-alternating excitation current is applied to the excitation conductor track, a signal that depends on the relative position is generated in the receiving conductor track during the relative movement of the rotor and the stator. These signals are then further processed in the evaluation electronics.

[0003] EP 4170289 A1 discloses an inductive position measuring mechanism having receiving conductors interrupted by gaps, this construction method contributing to reducing sensitivity to pitch tilt. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] EP4170289A1 Summary of the Invention [Problem to be solved by the invention]

[0005] The problem on which the invention is based is to provide a scanning element for an inductive position measuring mechanism which operates relatively accurately, is compact, can be manufactured inexpensively and is relatively insensitive to pitch tilt movements. [Means for solving the problem]

[0006] This problem is solved according to the invention by the features of claim 1. The scanning element, which is suitable for and has been determined for an inductive position measuring mechanism, comprises a multi-layer printed circuit board with a first receiving conductor extending along a first direction. The printed circuit board additionally comprises an excitation track. The first receiving conductor comprises a number of first loops, which are made up of a number of first conductor segments. These first conductor segments run in different layers of the printed circuit board and are connected to one another in series, in particular by vias, thus forming an electrically connected conductor string. Along the subsection, two first conductor segments are arranged in the structure of the printed circuit board in the same manner, offset from one another with respect to a third direction (or in a third direction). The third direction is oriented perpendicular to the first direction. In particular, in the subsection, offset in the third direction, two loops run in different layers of the printed circuit board in the same manner, offset from one another in the third direction, which loops are made up of first conductor segments. Along a first subsection, which is arranged offset in the first direction relative to the subsection, a further one of the first conductor fragments runs in the structure of the printed circuit board, along which, however, a similar conductor fragment is not arranged offset in a third direction relative to the further first conductor fragment, i.e., along a first subsection, which is arranged offset in the third direction relative to the further first conductor fragment, a further one of the first conductor fragments runs in the structure of the printed circuit board, and there is not a similar first conductor fragment running offset in the third direction relative to the further first conductor fragment.

[0007] The first direction is the direction in which the desired position is measured (measurement direction). According to one embodiment, the position measuring mechanism with the scanning element is to measure the relative angular position between the scale element and the scanning element, so that in this case the first direction is circumferential or tangential. Alternatively, the first direction can also be a linear direction if a relative displacement is to be measured.

[0008] In addition, a second direction may be defined that runs orthogonal to the first direction. A third direction is oriented orthogonal to the first direction and simultaneously orthogonal to the second direction. The third direction is oriented orthogonal to the plane of the printed circuit board, and in addition the individual layers of the printed circuit board are offset relative to one another in the third direction. In the case of measuring the angular position the third direction runs parallel to the (rotational) axis about which the scale element can be rotated relative to the scanning element.

[0009] That is, the scanning element can scan a linear scale or a curved, in particular circular or arcuate, scale element, so that a linear or angular position can be measured. That is, the first receiving conductor can extend along a first direction over a linear or curved section. This section includes a subarea, in particular a subsection and a first subsection.

[0010] Similar conductor segments are conductor segments which run essentially in the same direction, in particular in the form of parallel curves or which run parallel to one another in a geometric sense. In particular, in the structure of the printed circuit board, two first conductor segments can be arranged along a subsection in the third direction such that they overlap each other in the third direction, or at least their start points and end points can overlap. The start points and end points can be formed as vias.

[0011] These similar conductor segments receive or generate signals having the same phase, so that the series connection of similar conductor segments results in an increase in the signal level.

[0012] Advantageously, the first conductor segment of the first receiving conductor runs exactly on four layers of the printed circuit board. When measuring the angular position, the scale element and the scanning element are arranged rotatably relative to each other around an axis as mentioned above. It is particularly advantageous for measuring the angular position if the first receiving conductor extends in a first direction along an arch segment that spans a first central angle of less than 180°, in particular less than 135°, preferably less than 90°. The central angle is the central point angle around a point on the axis.

[0013] In a further embodiment of the invention, exactly two first conductor segments are arranged in the same way along the subsection and are offset relative to one another in the third direction, whereas exactly one further first conductor segment runs along the first subsection, and no first conductor segment also runs offset relative to this further first conductor segment in the third direction.

[0014] Advantageously, the first receiving conductor has a periodic path with a period length along the first direction, and the first subsection extends in the first direction over a length at least equal to half the period length. The period length can be an angular dimension or radians for the measurement of the angular position, and therefore the period length can be presented, for example, in degrees. Correspondingly, the length over which the subsection extends in the first direction can also be presented as an angular dimension.

[0015] Advantageously, the partial section is arranged offset in the first direction relative to the first partial section. Advantageously, the multilayer printed circuit board also comprises a second receiving conductor, which extends along a linear or curved section in the first direction and is arranged offset in the first direction with respect to the first receiving conductor. The second receiving conductor in turn comprises a number of second loops, which are made up of a number of second conductor segments. The second conductor segments are connected in series and thus form an electrically connected conductor string. In the structure of the printed circuit board, two second conductor segments are arranged in the same manner along the subsection and are arranged offset from one another in the third direction. Along the second subsection, which is arranged offset in the first direction with respect to the subsection, a further one of the second conductor segments runs, and there is not a second conductor segment running in the same manner offset in the third direction with respect to this further second conductor segment.

[0016] The first and second receiving conductors are present on one and the same receiving track. The second receiving conductor, like the first receiving conductor, may extend along a linear or curved section along a first direction. This section includes a sub-area, in particular a sub-section and a second sub-section.

[0017] Advantageously, the first and second receiving conductors each have a periodic trajectory along the first direction, each having the same period length. In a further embodiment of the invention, the first subsection is offset in the first direction relative to the second subsection, such that the first and second subsections do not overlap.

[0018] It is advantageous if the first conductor segment of the first receiving conductor and the second conductor segment of the second receiving conductor, i.e. both receiving conductors together, run exactly on four layers in the structure of the printed circuit board.

[0019] It is advantageous for the second receiving conductor to extend in the first direction along an arch segment that spans a second central angle of less than 180°, in particular less than 135°, advantageously less than 90°. In this regard, the second receiving conductor may extend in the first direction along an arch segment that spans a central angle of similar magnitude to the first receiving conductor, the first receiving conductor being arranged offset in the first direction with respect to the second receiving conductor.

[0020] In a further embodiment of the invention, along the subsection exactly two second conductor fragments are arranged in the same manner in the structure of the printed circuit board, offset relative to one another in the third direction, and along the second subsection exactly one second conductor fragment runs in the structure of the printed circuit board, and no further second conductor fragments run in the same manner offset relative to this second conductor fragment in the third direction.

[0021] Preferably, the excitation track surrounds the first and second receiving conductors. Advantageously, the second receiving conductor has a periodic track along the first direction with a period length, the second partial section extending in the first direction over a length at least equal to half the period length.

[0022] It is advantageous for the first and second receiving conductors to have periodic tracks along a first direction, each with a periodic length, and for the first partial section to extend over a certain length in the first direction and for the second partial section to extend over the same length.

[0023] Advantageous configurations of the invention can be seen from the dependent claims. Further details and advantages of the scanning element according to the invention become apparent from the following description of one exemplary embodiment based on the attached drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 2 is a plan view of a scanning element. [Diagram 2] FIG. 2 is a cross-sectional detail of a scanning element. [Diagram 3] FIG. 2 is a plan view of a scale element. [Figure 4] FIG. 4 is a plan view of a scale element in detail. [Diagram 5] Figure 5a is a detailed plan view of a first conductor segment of a first layer of a printed circuit board of the scanning element; Figure 5b is a detailed plan view of a first conductor segment of a second layer of a printed circuit board of the scanning element; Figure 5c is a detailed plan view of a first conductor segment of a third layer of a printed circuit board of the scanning element; Figure 5d is a detailed plan view of a first conductor segment of a fourth layer of a printed circuit board of the scanning element; and Figure 5e is a detailed plan view of the first conductor segments of all four layers of a printed circuit board of the scanning element. [Figure 6] Figure 6a is a detailed plan view of a second conductor segment in a first layer of the printed circuit board of the scanning element. Figure 6b is a detailed plan view of a second conductor segment in a second layer of the printed circuit board of the scanning element. Figure 6c is a detailed plan view of a second conductor segment in a third layer of the printed circuit board of the scanning element. Figure 6d is a detailed plan view of a second conductor segment in a fourth layer of the printed circuit board of the scanning element. Figure 6e is a detailed plan view of second conductor segments of all four layers of the printed circuit board of the scanning element. [Figure 7] FIG. 2 is a detailed plan view of the first and second receiving conductor paths. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] With reference to FIG. 1, the invention will be explained on the basis of a position measuring mechanism with a scanning element comprising a printed circuit board 1 . This scanning element can be used to capture the angular position of a scale element 2, which is shown in a plan view in Fig. 3. The scale element 2 has a disk-like or ring-like shape and is arranged rotatably about an axis R relative to the printed circuit board 1. The scale element 2 consists of a base, which in the illustrated exemplary embodiment is made of epoxy resin, on which three graduation tracks 2.1, 2.2, 2.3 are arranged. The graduation tracks 2.1, 2.2, 2.3 are formed in the shape of rings and are arranged on the base concentrically with respect to the axis R and with different diameters. The graduation tracks 2.1, 2.2, 2.3 each comprise a graduation structure consisting of a periodic sequence of alternating conductive graduation fields 2.11, 2.21, 2.31 and non-conductive graduation fields 2.12, 2.22, 2.32 (Fig. 4). As material for the conductive graduation fields 2.11, 2.21, 2.31, copper is applied to the base in the illustrated example. In contrast, the base was not coated in the non-conductive graduation areas 2.12, 2.22, 2.32. Alternatively, the scale element can also be designed in such a way that it has a steel base that is coated with an insulating layer onto which the graduation areas, for example made of copper, are applied.

[0026] Due to the configuration with three graduation tracks 2.1, 2.2, 2.3, the angular position of the scale element 2 can be determined in an absolute manner. The middle graduation track 2.1 of the scale element 2 has the greatest number of graduation fields 2.11, 2.12 along the circumference, here 182 pairs, so that the greatest resolution can be achieved with the middle graduation track 2.1 for measuring the angular position. The inner graduation track 2.3 has the smallest number of graduation fields 2.31, 2.32 along the circumference, which in the presented exemplary embodiment is 168 conductive graduation fields 2.31 and 168 non-conductive graduation fields 2.32, respectively. Finally, the outer graduation track 2.2 has the middle number, here 169 pairs of graduation fields 2.21, 2.22, which is less than the number of the middle graduation track 2.1.

[0027] 1 shows a plan view of a printed circuit board 1. The printed circuit board 1 comprises three receiving tracks D, E, F which extend along a first direction x, which may also be called the measuring direction, running circumferentially around an axis R.

[0028] FIG. 2 shows a schematic partial cross-section of the printed circuit board 1, which is not to scale so as to better illustrate the scanning element 1 according to the invention. The printed circuit board 1 is a multi-layer structure, as already mentioned above, and thus 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) mounted on it. The geometrical relationship of the individual elements to one another can be defined by means of a coordinate system. In this respect, the first direction x is the direction along which a position or angle measurement is to be performed as specified. In the presented exemplary embodiment, the first direction x corresponds to the circumferential direction. The axis R about which the scale element 2 can rotate runs parallel to the third direction z, which can therefore also be defined here as the axial direction. A second direction y is oriented perpendicular to the third direction z and to the first direction x, which may also be called the radial direction. That is, according to FIG. 2, the conductive layers L1 to L4 are arranged to be shifted from one another in the third direction z.

[0029] The receiving tracks D, E, F run in bands with a defined radial extent in each of the four conductive layers L1-L4. The conductive layers L1-L4 are structured in such a way that a first receiving conductor 1.1 and a second receiving conductor 1.2 are formed according to FIG. 1. The two receiving conductors 1.1, 1.2 are arranged offset from one another in a first direction x (circumferential direction) so that they can provide two phase-shifted signals corresponding to the offset. The receiving conductors 1.1, 1.2 are formed as ring segments and extend in a first direction x (measuring direction). The scale element 2 is therefore only scanned along one circumferential segment and not simultaneously over the entire circumference, as is the case in the state of the art. In the presented exemplary embodiment, the first receiving conductor 1.1 extends in the first direction x along one arc segment over a first central angle α1 of about 25°. The second receiving conductor 1.2 also extends in the first direction x along an arch segment spanning a second central angle α2 which differs only slightly from α1. For all three receiving tracks D, E, F, the structure of the receiving tracks is exemplarily described based on the radially middle first receiving track D.

[0030] According to Fig. 5e, the first receiving conductor 1.1 comprises a number of first loops 1.11, which in turn are made up of a number of first conductor segments 1.111 connected in series. In addition, the first conductor segments 1.111 are connected with vias and run in different layers L1-L4 to avoid undesired short circuits. Although strictly speaking the first receiving conductor 1.1 is made up of many conductor segments 1.111 arranged side by side and allocated to different layers L1-L4, in the following such a structure will be referred to as one receiving conductor 1.1.

[0031] In Fig. 5a-5d, the trajectories of the first conductor fragments 1.111 in the four layers L1-L4 are shown separately in partial areas in the first direction x, and for the sake of clarity, not all first conductor fragments 1.111 are labeled. The layer L1 is here the top layer, followed in this case by the second, third and fourth layers L2-L4, respectively below it (shifted in the -z-direction), with the fourth layer L4 being the bottom layer in this case. Fig. 5e shows a plan view of the printed circuit board 1, in which all four layers L1-L4 are visible with the first layer L1 as the top layer. It is preferred that the first conductor fragments 1.111 have at their ends through holes or vias, respectively, to the layers L1-L4 above or below them. For the sake of illustration, the contacts or connections of the individual first conductor fragments 1.111 are shown by dashed lines in Fig. 5a-5d. In addition, arrows are inserted in Fig. 5a to 5d, which clarify which first conductor fragments 1.111 are arranged in the same way, in particular parallel, with a shift in the third direction z. In this regard, the first conductor fragments 1.111, which are pointed to by arrows with the same hatching arranged on top of each other in Fig. 5a to 5d, are arranged on top of each other in the structure of the printed circuit board 1. For example, the first conductor fragment 1.111 pointed to by the vertically hatched arrow with the symbol p1 is offset in the third direction z with respect to the first conductor fragment 1.111 pointed to by the vertically hatched arrow with the symbol q1. As is clear from Fig. 5b and Fig. 5c, the first conductor fragments 1.111 in question also run on top of each other in the same way, in particular parallel, in layers L2 and L3. This parallel arrangement of the first conductor segments 1.111 in the various layers L1-L4 is interrupted in a first partial section B1, in which a connection is made from the fourth layer L4 to the first layer L1 for the series connection of the individual first conductor segments 1.111. In this connection, the first conductor segment 1.111, which in FIG. 5d is pointed to by an arrow with the symbol r1, is first electrically connected to the short first conductor segment 1.111 in the third layer L3.This short first conductor segment 1.111 in the third layer L3 is also connected on the other side to the short first conductor segment 1.111 in the second layer L2. At the other end of the short first conductor segment 1.111 in the second layer L2, a contact is made to the first conductor segment 1.111 in the first layer L1, which is pointed to by the arrow with the sign s1. In this way, the first conductor segment 1.111 in the fourth layer L4 is electrically connected in stages to the first conductor segment 1.111 in the first layer L1. In addition, the design described herein of the first partial section B1 provides a place for a second receiving conductor 1.2, which is made up of second conductor fragments 1.211, which, although not shown in Figures 5a to 5d, also run within the four layers L1 to L4 and cross the first conductor fragments 1.111, electrically insulated from one another within the different layers L1 to L4.

[0032] 5e shows a partial area of ​​the first receiving conductor 1.1, in which the loops 1.11 are formed from the individual first conductor fragments 1.111, as can be seen from FIGS. 5a to 5d. Along the partial section A, at least two first conductor fragments 1.111 are arranged in the structure of the printed circuit board 1 in the same way, in particular parallel, offset from one another in the third direction z. In other words, in the partial section A, the loops 1.11 run in the structure of the printed circuit board 1 in the same way, in particular parallel, overlapping one another. In contrast, along the first partial section B1, at least one of the first conductor fragments 1.111 runs in the structure of the printed circuit board 1, and no further first conductor fragments 1.111 run in the same way, in particular parallel, offset from one of the first conductor fragments 1.111 in the third direction z. That is to say, in the first partial section B1, the loops 1.11 run in a single line and there are no further, in particular parallel, loops 1.11 offset in a third direction.

[0033] In Figures 6a to 6d the trajectories of the second conductor track fragments 1.211 in the four layers L1 to L4 are shown according to the representation in Figures 5a to 5d, while Figure 6e shows a plan view of the printed circuit board 1 in which all four layers L1 to L4 are visible with the first layer L1 as the top layer.

[0034] Each second conductor fragment 1.211 also has a through-hole to the layer L1-L4 above or below it. For the sake of illustration, the contacts or connections of the individual second conductor fragments 1.211 are shown by dashed lines in Fig. 6a-6d. In addition, arrows are also inserted in Fig. 6a-6d, which clarify which second conductor fragments 1.211 are arranged in the same way, in particular parallel, offset from one another in the third direction z. In this regard, the second conductor fragments 1.211, which are pointed to by arrows with the same hatching arranged on top of one another in Fig. 6a-6d, are arranged on top of one another in the structure of the printed circuit board 1. Correspondingly, the second conductor fragment 1.211, which is pointed to by a vertically hatched arrow with the symbol p2, is offset in the third direction z with respect to the second conductor fragment 1.211, which is pointed to by a vertically hatched arrow with the symbol q2. As can be seen from Fig. 6b and Fig. 6c, the second conductor fragments 1.211 in question also run in the same way, in particular parallel, to one another in the layers L2 and L3. This parallel arrangement of the second conductor fragments 1.211 in the various layers L1-L4 is interrupted in the second partial section B2, in which a connection is made from the fourth layer L4 to the first layer L1 for the series connection of the individual second conductor fragments 1.211. In this connection, the second conductor fragment 1.211, which in Fig. 6d is pointed by an arrow with the symbol r2, is first electrically connected with the short second conductor fragment 1.211 in the third layer L3. This short second conductor fragment 1.211 in the third layer L3 is on the other hand also connected with the short second conductor fragment 1.211 in the second layer L2. At the other end of the short second conductor segment 1.211 in the second layer L2, contact is made to the second conductor segment 1.211 in the first layer L1, which is pointed to by the arrow with the symbol s2. In this way, the second conductor segment 1.211 in the fourth layer L4 is electrically connected in stages to the second conductor segment 1.211 in the first layer L1.In addition, the design described herein of the second partial section B2 provides a place for a first receiving conductor 1.1, which is made up of first conductor fragments 1.111, which, although not shown in Figures 6a to 6d, also run within the four layers L1 to L4 and cross the second conductor fragments 1.211, electrically isolated from one another within the different layers L1 to L4.

[0035] Fig. 6e shows a partial area of ​​the second receiving conductor 1.2, in which, as can be seen from Figs. 6a-6d, loops 1.21 are formed from the individual second conductor fragments 1.211. Along the partial section A, at least two second conductor fragments 1.211 are arranged in the structure of the printed circuit board 1 in the same manner, in particular parallel, offset from one another in the third direction z. In other words, in the partial section A, the loops 1.21 run in the structure of the printed circuit board 1 in the same manner, in particular parallel, overlapping one another. In contrast, along the second partial section B2, at least one of the second conductor fragments 1.211 runs in the structure of the printed circuit board 1, and no further second conductor fragments 1.211 run in the same manner, in particular parallel, offset from one of the second conductor fragments 1.211 in the third direction z. That is to say, in the second subsection B2, the loop 1.21 runs in a single line and there are no further parallel loops 1.21 offset in a third direction.

[0036] The receiving conductors 1.1, 1.2 or the associated loops 1.11, 1.21 have a spatially periodic trajectory that is substantially sinusoidally or sinusoidally shaped. The first receiving conductor 1.1 and the second receiving conductor 1.2 of the receiving track D have a first period length λ1. The receiving conductors 1.4, 1.5 of the receiving track E each have a second period length λ2, and the receiving conductors 1.6, 1.7 of the receiving track F each have a third period length λ3. In the presented exemplary embodiment, the first period length λ1 is smaller than the second period length λ2, which is smaller than the third period length λ3 (λ1<λ2<λ3), the period lengths λ1, λ2, λ3 being presented here as angular dimensions in degrees.

[0037] In the presented exemplary embodiment, the first and second receiving conductors 1.1, 1.2 are arranged in the receiving track D such that they provide signals at 0° and 90°, i.e. are offset in a first direction. The same considerations apply to the receiving tracks E, F, whose receiving conductors 1.4, 1.5, 1.6, 1.7 also provide signals at 0° and 90°.

[0038] The first receiving track D provides a position signal with a higher resolution than both other receiving tracks E, F, especially since the first period length λ1 is smaller than the second period length λ2. In Fig. 7, the first receiving conductor 1.1 and the second receiving conductor 1.2, i.e. the loops 1.11, 1.21 formed therefrom, are shown overlapping as they are in the structure of the printed circuit board 1. In the first subsection B1, vias are present, which electrically connect the first conductor fragment 1.111 in the fourth layer L4 stepwise to the first conductor fragment 1.111 in the first layer L1. Similarly, in the second subsection B2, a second conductor fragment 1.211 is present, which is likewise electrically connected stepwise to the second conductor fragment 1.211 in the first layer L1 by a via. Vias are also visible in Fig. 7 at the edges of the first subsection B1 and the second subsection B2. These vias are, so to speak, cusps for the loops 1.11, 1.21, so that in the subsection A the loops 1.11, 1.21 are duplicated in the structure of the printed circuit board 1 and are parallel on different layers L1-L4, offset from one another in the third direction. In contrast, in the first subsection B1 the loop 1.11 and in the second subsection B2 the loop 1.21 are each formed only once. Although four conductor rows of the receiving conductors 1.1, 1.2 run within one periodic length λ1, here, due to the series connection and the cusps, only two phases are scanned, i.e. only two signals (0°, 90° signals) are generated.

[0039] The printed circuit board 1 further comprises an excitation track 1.3, which here has two excitation conductor tracks. The excitation track 1.3 surrounds the first and second receiving tracks 1.1, 1.2.

[0040] In the assembled state, the printed circuit board 1 and the scale element 2 face each other with an axial distance or gap between them, so that when the scale element 2 and the printed circuit board 1 rotate relative to each other, signals that depend on the respective angular position can be generated by inductive effects in the receiving tracks D, E, F, and in particular also in the receiving conductors 1.1, 1.2. A prerequisite for the generation of corresponding signals is that the excitation conductors of the excitation track 1.3 generate an electromagnetic excitation field that alternates over time in the area of ​​the respective graduation structure to be scanned. In the illustrated exemplary embodiment, the excitation conductors are designed as a number of single conductors that are pierced by a current in parallel planes. The scanning element has an electronic circuit with electronic components on the printed circuit board 1, which are electrically connected to one another via further layers of the printed circuit board 1 (not shown).

[0041] When the excitation track 1.3 is energized with the appropriate current direction, a tubular or cylindrically oriented electromagnetic field is generated around the excitation conductor track. The field lines of this resulting electromagnetic field run around the excitation track 1.3, and their direction depends, as is known, on the current direction in the excitation conductor track. Eddy currents are induced in the area of ​​the conductive graduation areas 2.11, 2.21, 2.31, as a result of which a field modulation is achieved depending on the angular position in each case.

[0042] Correspondingly, the relative angular position can be measured by the receiving conductors 1.1, 1.2. The receiving conductors 1.1, 1.2 are arranged in such a way that they provide signals that are phase shifted by 90°, so that the direction of rotation can also be determined. The signals generated by the receiving conductors 1.1, 1.2 are further processed by several electronic components that form an evaluation circuit. The signal of the first receiving track D, when scanning the central graduation track 2.1 of the scale element 2, provides the greatest or finest resolution of the angular position.

[0043] Precisely in a segment scanning as provided here, in which the first receiving conductor 1.1 runs along an arch segment in the first direction x, it is advantageous if the relative pitch movement, i.e. the torsional movement between the printed circuit board 1 and the scale element 2 around the pitch axis, which is oriented radially here, perpendicular to the first direction x, does not result in significant measurement errors in determining the angular position. By the printed circuit board 1 provided here or by the scanning element provided here, such errors caused by the pitch movement can be corrected in a large range. In addition to this, the configuration of the receiving conductors 1.1, 1.2 allows extremely high signal strengths to be achieved. [Explanation of symbols]

[0044] 1 Printed circuit board 1.1 First receiving conductor 1.11 First Loop 1.111 First conductor segment 1.2 Second receiving conductor 1.21 Second Loop 1.211 Second conductor section 1.3 Excitation track 2 Scale elements 2.1, 2.2, 2.3 Scale track 2.11, 2.21, 2.31 Conductive scale area 2.12, 2.22, 2.32 Non-conductive scale area A subinterval B1 First subdivision B2 Second subdivision D, E, F Received Tracks L1 First conductive layer L2 Second conductive layer L3 Third conductive layer L4 Fourth conductive layer x first direction y second direction z third direction α1 First central angle α2 Second central angle λ1 First period length λ2 Second period length λ3 Third period length

Claims

1. A scanning element for an inductive position measuring mechanism comprising a multi-layer printed circuit board (1) having a first receiving conductor (1.1) and an excitation track (1.3) extending along a first direction (x), the first receiving conductor (1.1) is made up of a plurality of first conductor segments (1.111) connected in series, Along the subsection (A), two first conductor track segments (1.111) are arranged in the same manner in the structure of the printed circuit board (1) with a mutual offset in a third direction (z), the third direction (z) being oriented perpendicular to the first direction (x), and A scanning element, along which a further one of the first conductor path segments (1.111) runs in the structure of the printed circuit board (1) along a first partial section (B1) which is arranged offset in the first direction (x) with respect to the partial section (A), and in which one first conductor path segment (1.111) is not arranged offset in the third direction (z) in the same way with respect to the further first conductor path segment (1.111).

2. 2. The scanning element according to claim 1, wherein the first conductor segment (1.111) of the first receiving conductor (1.1) runs exactly on four layers (L1, L2, L3, L4) of the printed circuit board (1).

3. 3. A scanning element according to claim 1 or 2, wherein the first receiving conductor (1.1) extends in the first direction (x) along one arch segment subtending a first central angle (α1) of less than 180°.

4. 4. A scanning element as claimed in claim 1, wherein along the partial section (A), exactly two first conductor path fragments (1.111) are arranged in the same manner within the structure of the printed circuit board (1) offset from one another in the third direction (z), and along the first partial section (B1), exactly one further first conductor path fragment (1.111) runs within the structure of the printed circuit board (1).

5. 5. A scanning element as claimed in claim 1, wherein the first receiving conductor path (1.1) has a periodic orbit with a period length (λ1) along the first direction (x) and the first partial section (B1) extends in the first direction (x) over a length at least equal to half the period length (λ1).

6. 6. A scanning element according to claim 1, wherein the partial section (A) is arranged offset in the first direction (x) with respect to the first partial section (B1).

7. The multilayer printed circuit board (1) includes a second receiving conductor (1.2) extending along the first direction (x), the second receiving conductor (1.2) is made up of a number of second conductor segments (1.211) connected in series, along said partial section (A), two second conductor track segments (1.211) are arranged in the same manner in the structure of the printed circuit board (1) with a mutual offset in the third direction (z), and 7. A scanning element as claimed in claim 1, wherein a further one of the second conductor path segments (1.211) runs along a second partial section (B2) which is arranged offset in the first direction (x) with respect to the partial section (A) in the structure of the printed circuit board (1), and a second conductor path segment (1.211) is not arranged offset in the third direction (z) in the same way with respect to the further second conductor path segment (1.211).

8. 8. The scanning element according to claim 7, wherein the first receiving conductor (1.1) and the second receiving conductor (1.2) have periodic orbits along the first direction (x), each having the same period length (λ1).

9. 9. A scanning element according to claim 7 or 8, wherein the first partial section (B1) is arranged offset in the first direction (x) with respect to the second partial section (B2).

10. 10. The scanning element according to claim 7, 8 or 9, wherein the first conductor path segment (1.111) of the first receiving conductor path (1.1) and the second conductor path segment (1.211) of the second receiving conductor path (1.2) run precisely on four layers (L1, L2, L3, L4) of the printed circuit board (1).

11. 11. A scanning element according to claim 7, wherein the second receiving conductor (1.2) extends in the first direction (x) along an arc segment that spans a second central angle (α2) of less than 180°.

12. 12. A scanning element as claimed in claim 7, wherein the first receiving conductor (1.1) extends in the first direction (x) along an arch segment spanning a first central angle (α1) of less than 180°, and the second receiving conductor (1.2) extends in the first direction (x) along an arch segment spanning a second central angle (α2) of less than 180°, and the first receiving conductor (1.1) is arranged offset in the first direction (x) with respect to the second receiving conductor (1.2).

13. 13. A scanning element as claimed in claim 7, wherein along the partial section (A) exactly two second conductor path fragments (1.211) are arranged in the same manner within the structure of the printed circuit board (1) offset from one another in the third direction (z), and along the second partial section (B2) exactly one of the second conductor path fragments (1.211) runs within the structure of the printed circuit board (1).

14. 14. A scanning element as claimed in claim 7, wherein the second receiving conductor (1.2) has a periodic trajectory with a period length (λ1) along the first direction (x) and the second partial section (B2) extends in the first direction (x) over a length at least equal to half the period length (λ1).

15. 15. A scanning element as claimed in claim 7, wherein the first receiving conductor (1.1) and the second receiving conductor (1.2) have a periodic orbit along the first direction (x), each with a period length (λ1), and in the first direction (x), the first partial section (B1) extends over a certain length and the second partial section (B2) extends over a certain length, the lengths being the same.

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