Scanning element and inductive position measuring device with the same

Abstract

To provide a scanning element and an inductive position measuring device having the scanning element.SOLUTION: The invention relates to a scanning element (1) for an inductive position measuring device, comprising a printed circuit board (1.1). The printed circuit board (1.1) has a geometric center plane (M) which lies between two detector units (1.11, 1.12). The detector units (1.11, 1.12) comprise receiver conductor tracks (1.1121, 1.1241), the first detector unit (1.11) further comprising a first connection conductor track (1.116). The first connection conductor track (1.116) is electrically connected to one of the first receiver conductor tracks (1.1121) and runs through the first gap (U1) with a radial directional component. The second detector unit (1.12) comprises a second connection conductor track (1.126). The second connection conductor track (1.126) is electrically connected to one of the fourth receiver conductor tracks (1.1241) and runs through the second gap (U2) with a radial directional component.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The invention relates to a scanning element for an inductive position measuring device according to claim 1 for determining the position of the scanning element relative to two scale elements which can rotate at different speeds, and to a position measuring device equipped with such a scanning element. [Background technology]

[0002] Inductive position measuring devices are used, for example, as angle measuring instruments to determine the angular position of machine parts that can rotate relative to one another. In inductive position measuring devices, excitation and receiving lines are often arranged in the form of conductor tracks or the like on a common, usually multilayer, printed circuit board, which is fixedly connected, for example, to the stator of the angle measuring device. Opposite this printed circuit board is a scale element that has a pitch structure and is non-rotatably connected to the rotor of the angle measuring device. When a time-varying excitation current is applied to the excitation lines, a signal dependent on the angular position is generated in the receiving coil during relative rotation of the rotor and stator. These signals are then further processed by the evaluation electronics.

[0003] In particular, in robot drives, inductive position measuring devices are frequently used as measuring devices for determining the angular position of a drive shaft and simultaneously accurately determining the angular position of a driven shaft, the movement of which is introduced into the driven shaft by a reducer. In this case, the angular position or angular position is measured using a scanning element which comprises a printed circuit board with corresponding detector units on both sides, so that the respective angular positions of scale elements which are rotatably arranged on both sides of the printed circuit board can be determined.

[0004] JP 2006-208239 discloses a position measuring device with two rotors between which a stator is arranged, in particular according to Figure 6 of this document. The position measuring device described there is used, for example, with a micrometer screw. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2006-208239 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention is based on the problem of creating a scanning element for an inductive position measuring device that allows the position or angular position of first and second scale elements to be determined, operates relatively accurately, is compact and can be manufactured cheaply. [Means for solving the problem]

[0007] This problem is solved according to the invention by the features of claim 1. A scanning element suitable for and designed for an inductive position measuring device includes a printed circuit board with a first detector unit and a second detector unit. The first detector unit has a first excitation line, a first receiving line, and a third receiving line. The second detector unit has a second excitation line, a second receiving line, and a fourth receiving line. The printed circuit board has a geometric center plane disposed between the first and second detector units. The receiving lines are arranged circumferentially around the axis, and the third receiving line extends radially outward relative to the first receiving line. Similarly, the second receiving line extends radially outward relative to the fourth receiving line. The first receiving line includes a first receiving conductor, the second receiving line includes a second receiving conductor, the third receiving line includes a third receiving conductor, and the fourth receiving line includes a fourth receiving conductor. The first, second, third, and fourth receiving conductors each have a periodic path. The third receiving line has a first gap along its circumferential extension, the first gap being defined by the third receiving conductor. Similarly, the second receiving line has a second gap along its circumferential extension, the second gap being defined by the second receiving conductor. The first detector unit further includes a first connecting conductor, which is electrically connected or in contact with one of the first receiving conductors and extends through the first gap with a radial component. The second detector unit includes a second connecting conductor, which is electrically connected to one of the fourth receiving conductors and extends through the second gap with a radial component. The connecting conductor is, in particular, a connection section between both the first and fourth receiving conductors located inside and components of the electronic circuit.

[0008] In defining the spatial arrangement of the subject matter, a first direction x can be defined. The first direction x represents the direction (measurement direction) in which the determined position is measured. The first direction x is a circumferential or tangential direction since the position measuring device is to measure a first relative angular position between a first scale element and a scanning element and simultaneously a second relative angular position between a second scale element and a scanning element for a rotational or pivoting movement about an axis, respectively.

[0009] Additionally, a second direction y may be defined that is orthogonal to the first direction x. A third direction z is oriented perpendicular to the first direction x and perpendicular to the second direction y. The third direction z is parallel to an axis about which the scale element can rotate relative to the scanning element. Furthermore, the third direction z is perpendicular to the central plane. The layers of the printed circuit board are offset relative to one another in the third direction z.

[0010] Typically, both largest faces of a printed circuit board are oriented parallel to one another, and the central plane is in particular arranged parallel to and centered between these faces, so that the distance between one face of the printed circuit board and the central plane is exactly the same as the distance between the other face of the printed circuit board and the central plane, in particular in the third direction z.

[0011] In a further embodiment of the invention, the first gap is circumferentially offset relative to the second gap, so that both gaps do not overlap within the structure of the printed circuit board. According to one variant of the invention, the printed circuit board is configured in multiple layers, and the first detector units are arranged on the first and second layers of the printed circuit board. Furthermore, the second detector units are arranged on the third and fourth layers of the printed circuit board. Furthermore, in particular, the first connecting conductors may extend alternately on the first and second layers of the printed circuit board. Alternatively or additionally, the second connecting conductors may extend alternately on the third and fourth layers. In other words, at least one section of the first connecting conductor extends on the first layer, and another section of the first connecting conductor extends on the second layer. The same applies to the second connecting conductors.

[0012] Advantageously, the printed circuit board comprises electronic components, the second detector unit and at least one of the electronic components being arranged on the same side of the printed circuit board. Advantageously, the first and second excitation lines can be energized with an excitation current (alternating current or mixed current), which usually has a current intensity that varies over time. The excitation current can be generated by electronic components, i.e., its path can be formed by electronic components. Since there is a physical relationship between current intensity and voltage intensity, the same can naturally be considered for the excitation voltage.

[0013] Advantageously, the scanning element is configured such that the first excitation line and the second excitation line are electrically connected in series. In a further embodiment of the invention, the signals that can be generated by one or more of the receiving lines can be further processed by electronic components that in particular constitute an evaluation circuit.

[0014] That is, the electronic components may be elements of different electronic circuits or may be assigned to different circuits, for example, one electronic component may be a circuit element for generating an excitation current and a further electronic component may be a further circuit element for evaluating or further processing the signal.

[0015] Advantageously, both the receiving and excitation lines extend along the circumferential or first direction x. Advantageously, the first detector unit, in particular the first connecting conductor, is electrically connected to at least one electronic component via a via, which is arranged radially outside the second receiving line. In a further embodiment of the invention, the via is in electrical contact with one of the electronic components, so that a signal, in particular generated by the first detector unit or its receiving conductor, can be supplied to the electronic component via the via. The via may extend in particular in the third direction z.

[0016] In an advantageous embodiment of the invention, the via is implemented as a through-hole via. The via is in particular created by a continuous hole that passes through the printed circuit board. The hole is preferably provided with a metal layer, in particular a copper layer, on its inner wall. Contacts above and below the via form an electrical contact with a conductor track, a conductor layer, or an electronic component. In the following, the term via may also refer to an arrangement in which several holes or hollow spaces filled or coated with a conductive material are offset from one another (in particular radially or circumferentially). Such vias are often also called staggered vias.

[0017] In a further aspect of the invention, the first gap extends a first length in the circumferential direction, and the third receiving conductor has a periodic path with a third periodic length λ3, where the first length is greater than or equal to 1 / 8 of the third periodic length λ3, i.e., L1(first length)≧1 / 8·λ3.

[0018] Advantageously, the scanning element is configured such that the second gap extends a second length in the circumferential direction and the second receiving conductor has a periodic path with a second period length λ2, where the second length is greater than or equal to 1 / 8 of the second period length λ2, i.e., L2(second length)≧1 / 8·λ2.

[0019] In a further aspect of the invention, the first receiving conductor has a periodic path with a first period length λ1, and the third receiving conductor has a periodic path with a third period length λ3. The first period length λ1 is less than or equal to the third period length λ3 (λ1≦λ3). Furthermore, the periodic path of the second receiving conductor may have a second period length (λ2), and the fourth receiving conductor may have a fourth period length (λ4). The first period length (λ1) is less than or equal to all other period lengths λ2, λ3, and λ4, i.e., less than or equal to the second, third, and fourth period lengths (λ2, λ3, λ4).

[0020] Advantageously, the second period length (λ2) is less than or equal to the fourth period length (λ4). In an advantageous embodiment of the invention, the second detector unit and at least one of the electronic components are arranged on the same side of the printed circuit board, i.e., in this construction, the second detector unit and the electronic component are offset in the same direction relative to the central plane, so that the central plane is not located between the second detector unit and the electronic component.

[0021] In a further aspect of the invention, the first detector unit has a third excitation line and the second detector unit has a fourth excitation line. In an advantageous embodiment, the first shield layer is disposed on the fifth layer of the printed circuit board, and the second shield layer is disposed on the sixth layer of the printed circuit board, with the central plane being located between the first and second shield layers, such that the shield layers are disposed on either side of the central plane.

[0022] The central plane is located between the first detector unit and the first shield layer in the third direction z. Accordingly, it is equally true that the central plane is located between the second detector unit and the second shield layer in the third direction z, and that the second detector unit and the second shield layer are disposed on either side of the central plane.

[0023] According to a further aspect, the invention also includes an inductive position measuring device comprising a scanning element and first and second scale elements arranged spaced apart on opposite sides of the printed circuit board in a third direction z (a direction perpendicular to the central plane).

[0024] Advantageously, the first scale element has a first diameter D1 and the second scale element has a second diameter d2, the first diameter D1 being greater than the second diameter d2 (D1>d2). Additionally, the scale element may be arranged to be rotatable about a common axis relative to the scanning element.

[0025] Furthermore, at least one of the electronic components may be positioned further away from the axis than the outer contour of the second scale element, i.e., the at least one electronic component is positioned radially outward from the second scale element.

[0026] Advantageous configurations of the invention emerge from the dependent claims. Further details and advantages of the scanning element according to the invention will become apparent from the following description of one embodiment with reference to the accompanying drawings. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a perspective view of a position measuring device including a scanning element, a first scale element, and a second scale element. [Figure 2] FIG. 2 is a plan view of a first side of a scanning element. [Figure 3] FIG. 2 is a detailed plan view of a first side of the scanning element. [Figure 4] FIG. 4 is a plan view of a second side of the scanning element. [Figure 5] FIG. 4 is a detailed plan view of a second side of the scanning element. [Figure 6] Detailed cross-sectional view of the scanning element at PP. [Figure 7] FIG. 2 is a plan view of a first scale element. [Figure 8] FIG. 10 is a plan view of a second scale element. DETAILED DESCRIPTION OF THE INVENTION

[0028] The present invention will be described with reference to FIG. 1 with reference to a position measuring device having a scanning element 1 that can be used to detect both the angular position of a first scale element 2 and the angular position of a second scale element 3. The two scale elements 2, 3 are arranged rotatably about axis R relative to the scanning element 1. Such a position measuring device can be used, for example, in a robot drive. The second scale element 3 is then non-rotatably connected, for example, to a drive shaft of a motor, which in turn is connected to a reducer with a driven shaft. The first scale element 2 rotates together with this driven shaft. In this way, for example, the angular position for motor commutation can be determined using the second scale element 3, and the angular position for robot positioning with relatively high precision can be determined using the first scale element 2.

[0029] The scanning element 1 includes a printed circuit board 1.1 having several layers and an electronic component 1.2 mounted on the printed circuit board 1.1. The scanning element 1 is used to scan a first scale element 2 and a second scale element 3 simultaneously. In this embodiment, the electronic component 1.2 is mounted only on the second surface. However, it is also possible, alternatively or additionally, to mount the electronic component on the first surface of the printed circuit board 1.1.

[0030] To determine the angle information, a first detector unit 1.11 is arranged on a first side of the printed circuit board 1.1 and a second detector unit 1.12 is arranged on a second side of the printed circuit board 1.1. In Figure 1, the second side of the printed circuit board 1.1 with the second detector unit 1.12 is visible.

[0031] In Figures 2 and 3 (Figure 3 is an enlarged detailed view of the first detector unit 1.11 according to Figure 2), the first side of the printed circuit board 1.1 is shown, inter alia, with the first detector unit 1.11 located on the first outer layer A of the printed circuit board 1.1 and on the second outer layer B of the printed circuit board 1.1 (see Figure 6). The first detector unit 1.11 includes a first excitation line 1.111, a first receiving line 1.112, a third excitation line 1.113, a third receiving line 1.114, and a fifth excitation line 1.115. The first receiving line 1.112 includes a first receiving conductor 1.1121, and the third receiving line 1.114 includes a third receiving conductor 1.1141. The first and third receiving lines 1.112, 1.114 are arranged circumferentially around the axis R, with the third receiving line 1.114 extending radially outward relative to the first receiving line 1.112, i.e., radially outward of the first receiving line 1.112.

[0032] In Figures 4 and 5, the other side of the printed circuit board 1.1 is shown, revealing the second detector unit 1.12. Figure 5 shows an enlarged view of the second detector unit 1.12 in detail. Figures 4 and 5 show, inter alia, the structure of the second detector unit 1.12 on the outer fourth layer F of the printed circuit board 1.1 and on the third layer E of the printed circuit board 1.1. The second detector unit 1.12 includes a second excitation line 1.121, a second receiving line 1.122, a fourth excitation line 1.123, a fourth receiving line 1.124, and a sixth excitation line 1.125. The second receiving line 1.122 includes a second receiving conductor 1.1221, and the fourth receiving line 1.124 includes a fourth receiving conductor 1.1241. The second and fourth receiving wires 1.122, 1.124 are also arranged circumferentially around the axis R, with the second receiving wire 1.122 extending radially outward relative to the fourth receiving wire 1.124.

[0033] FIG. 6 shows a schematic partial cross-section of the scanning element 1 or printed circuit board 1.1 along the section line PP. For clarity, the hatching of the electrically insulating material of the printed circuit board 1.1 has been omitted. Furthermore, the partial cross-section of FIG. 6 is not drawn to scale in order to better illustrate the scanning element 1 according to the present invention. As already mentioned above, the printed circuit board 1.1 has a multi-layer structure. Geometrically, a so-called central plane M can be defined for the printed circuit board 1.1, which is located parallel to the first side surface and parallel to the second side surface of the printed circuit board 1.1, respectively, at the center between the first and second side surfaces. Furthermore, the geometric relationship of the individual elements to one another can be defined using a coordinate system. Here, the first direction x is the direction in which the position or angle measurement is intended to be performed. In this embodiment, the first direction x corresponds to the circumferential direction. The axis R about which the scale elements 2, 3 can rotate extends parallel to a third direction z, which may also be defined herein as the axial direction. A second direction y is oriented perpendicular to the third direction z and the first direction x, which may also be called the radial direction. Thus, the plane formed by the x- and y-axes is oriented parallel to the central plane M, and the third direction z and the axis R extend perpendicular to the central plane M.

[0034] A first detector unit 1.11 is arranged on the first layer A of the printed circuit board 1.1 and on the second layer B of the printed circuit board 1.1, while a second detector unit 1.12 is arranged on the third layer E and the fourth layer F. The first layer A is closest to the first side of the printed circuit board 1.1, and the second layer B is second closest to the first side of the printed circuit board 1.1. The same is true for the fourth layer F and the third layer E on the second side of the printed circuit board 1.1.

[0035] The excitation lines 1.111, 1.113, 1.115 of the first detector unit 1.11 include excitation conductor paths 1.1111, 1.1131, 1.1151 that extend to the first layer A. Similarly, the excitation lines 1.121, 1.123, 1.125 of the second detector unit 1.12 include excitation conductor paths 1.1211, 1.1231, 1.1251 that extend to the fourth layer F.

[0036] The printed circuit board 1.1 also includes a fifth layer D and a sixth layer C. The fifth layer D contains a first shielding layer 1.13, and the sixth layer C contains a second shielding layer 1.14. The shielding layers 1.13 and 1.14 are copper layers with relatively large areas. These shielding layers do not have perforations or openings, particularly in the areas between the receiving lines 1.112, 1.114, 1.122, and 1.124. This prevents or at least strongly reduces crosstalk between the receiving lines 1.112 and 1.114 of the first detector unit 1.11 and the receiving lines 1.122 and 1.124 of the second detector unit 1.12.

[0037] The excitation wires 1.111, 1.113, 1.115 of the first detector unit 1.11 surround the first receiving wire 1.112 or the third receiving wire 1.114. The excitation wires 1.121, 1.123, 1.125 of the second detector unit 1.12 surround the second receiving wire 1.122 or the fourth receiving wire 1.124. Both the excitation wires 1.111, 1.113, 1.115, 1.121, 1.123, 1.125 and the receiving wires 1.112, 1.114, 1.122, 1.124 extend in the circumferential or first direction x.

[0038] In this embodiment, the receiving lines 1.112, 1.114, 1.122, and 1.124 respectively include receiving conductors 1.1121, 1.1141, 1.1221, and 1.1241, which are circumferentially offset, thereby providing four signals with corresponding phase shifts. In the figure, the receiving conductors 1.1121, 1.1141, 1.1221, and 1.1241 belonging to the same receiving line 1.112, 1.114, 1.122, and 1.124 are given a single reference number. Thus, for example, all receiving conductors 1.1121 of the first receiving line 1.112 are given a single reference number. Furthermore, the first receiving conductors 1.1121 of the first detector unit 1.11 are connected with vias and run on different layers of the printed circuit board 1.1, thereby avoiding undesired short circuits at crossing points. The same is true for the receiving conductors 1.1221, 1.1241 of the second detector unit 1.12. Strictly speaking, each of the first and second receiving conductors 1.1121, 1.1221 consists of a number of conductor pieces arranged side by side and distributed over two planes or layers, respectively, but in the following such structures will be collectively referred to as a single receiving conductor 1.1221, 1.1241.

[0039] The receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 have a spatially periodic path that is approximately sinusoidal or sinusoidal. With respect to the first detector unit 1.11, the first receiving conductor 1.1121 of the first receiving line 1.112 has a first periodic length λ1, and the third receiving conductor 1.1141 has a third periodic length λ3. In this embodiment, based on FIG. 3, the first periodic length λ1 is smaller than the third periodic length λ3 (λ1<λ3=2 1 / 2λ3, FIG. 3). With respect to the second detector unit 1.12 (see FIG. 5), it can be seen that the second receiving conductor 1.1221 of the second receiving line 1.122 has a second periodic length λ2, and the fourth receiving conductor 1.1241 has a fourth periodic length λ4. Here, the second period length λ2 is smaller than the fourth period length λ4, and in particular, with respect to FIG. 2 1 / 2λ=λ2<λ4=2 1 / 2λ4 holds true.

[0040] In this embodiment, adjacent receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 within one receiving line 1.112, 1.114, 1.122, 1.124 are offset from each other by 1 / 8 of a complete sine period or period length λ1, λ2, λ3, λ4 (π / 4 or 45° along the circumferential or first direction x). The receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 are electrically connected to provide 0° and 90° signals on one side and 45° and 135° signals on the other side. A first position signal can be determined from the 0° and 90° signals, and a second position signal redundant to the first position signal can be determined from the 45° and 135° signals.

[0041] As shown in FIGS. 2 and 3, the third receiving line 1.114 has a first gap U1 along its extension in the circumferential direction (x-direction). The area of ​​the first gap U1 is defined by the third receiving conductors 1.1141, so that no detection structures are present between the defined receiving conductors 1.1141. In other words, to a first approximation, the first gap U1 is also a region that is a geometrically segmented ring. In the area of ​​the first gap U1, the minimum circumferential distance L1 between two third receiving conductors 1.1141 is 5 / 8 λ3 ​​(L1 = 5 / 8 λ3) in this embodiment. That is, no periodically extending third receiving conductors 1.1141 are arranged in the area of ​​the first gap U1. In contrast, the first connecting conductor 1.116 extends with a radial component through the first gap U1. The first connecting conductor 1.116 is electrically connected to the first receiving conductor 1.1121 of the first receiving line 1.112 located further inside and serves to transmit the received signal to the outside. To avoid interference coupling in the area of ​​the first connecting conductor 1.116, the first connecting conductor 1.116 extends alternately in the z-direction onto the first and second layers A and B of the printed circuit board 1.1.

[0042] The printed circuit board 1.1 further includes vias 1.15. The first connecting conductor 1.116 terminates in the vias 1.15, which are arranged radially outside the third receiving line 1.114. The vias 1.15 are each implemented as through-hole vias and thus penetrate the entire thickness of the printed circuit board 1.1. The vias 1.15 thus extend parallel to the third direction z. The vias 1.15 are arranged radially outside the second receiving line 1.122 on the second side of the printed circuit board 1.1, i.e., on the side of the second detector unit 1.12. This side is where the electronic component 1.2 is located. The vias 1.15 electrically connect the first receiving conductor 1.1121 of the first receiving line 1.112 to the electronic component 1.2, which is arranged across the central plane M. Electrical contact is made to the electronic component 1.2 via the conductors. The first receiving conductor 1.1121 is thus electrically connected to the electronic component 1.2 via the connecting conductor 1.116 and the via 1.15.

[0043] 4 and 5, the second receiving line 1.122 has a second gap U2 along its circumferential extension. This second gap U2 is defined by the second receiving conductors 1.1221. In the region of the second gap U2, the minimum circumferential distance L2 between two second receiving conductors 1.1221 is 5 / 8 λ2 (L2 = 5 / 8 λ2) in this embodiment. That is, no periodic second receiving conductors 1.1221 are arranged in the second gap U2. Through the second gap U2, second connecting conductors 1.126 extend with a radial component and are electrically connected to the respective fourth receiving conductors 1.1241. The second connecting conductors 1.126 run alternately one above the other in the z-direction on the third and fourth layers E and F of the printed circuit board 1.1 in order to avoid interference coupling.

[0044] In particular, because the first period length λ1 is smaller than the third period length λ3, the first receiver line 1.112 provides a higher resolution position signal than the third receiver line 1.114. That is, the first detector unit 1.11 has a higher resolution, inner receiver line 1.112 and a lower resolution, outer receiver line 1.114, which is interrupted by a first gap U1. The second detector unit 1.12 has a higher resolution, outer receiver line 1.122 compared to the fourth receiver line 1.124, which is interrupted by a second gap U2. The first gap U1 is circumferentially offset by an angle γ (FIG. 4) from the second gap U2.

[0045] Figure 7 shows a plan view of the first scale element 2. Figure 8 also shows a plan view of the second scale element 3. The scale elements 2 and 3 have a disk-like shape, with the first scale element 2 having a first diameter D1 and the second scale element 3 having a second diameter d2. The first diameter D1 is larger than the second diameter d2 (D1>d2).

[0046] In the illustrated embodiment, the scale elements 2 and 3 each comprise an epoxy resin substrate on which two pitch lines 2.1, 2.2; 3.1, 3.2 are disposed. The pitch lines 2.1, 2.2; 3.1, 3.2 are ring-shaped and are arranged on the substrate concentrically with respect to the axis R with different diameters. The pitch lines 2.1, 2.2; 3.1, 3.2 each comprise a pitch structure consisting of a periodic sequence of alternating conductive pitch regions 2.11, 2.21; 3.11, 3.21; and non-conductive pitch regions 2.12, 2.22; 3.12, 3.22. In the illustrated embodiment, copper is applied to the substrate as the material for the conductive pitch regions 2.11, 2.21; 3.11, 3.21. On the other hand, the substrate was left uncoated in the non-conductive pitch regions 2.12, 2.22; 3.12, 3.22. The arrangement with two pitch lines 2.1, 2.2; 3.1, 3.2 allows the angular position of each of the scale elements 2, 3 to be absolutely determined. The inner pitch line 2.1 of the first scale element 2 has the greatest number of pitch regions 2.11, 2.12 along its circumference, thereby providing the greatest resolution for measuring the angular position.

[0047] 1, the scanning element 1 and the scale elements 2, 3 are opposed to each other with an axial gap or air gap therebetween, so that in the event of a relative rotation between the scale elements 2, 3 and the scanning element 1, signals that depend on the respective angular position can be generated by induction in the receiving conductors 1.1121, 1.1141, 1.1221, 1.1241. The prerequisite for generating a corresponding signal is that the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251 each generate a time-varying electromagnetic excitation field in the region of the scanned pitch structure. In the illustrated embodiment, the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251 are configured as a number of parallel, planar, current-carrying individual conductors. The scanning element 1 has an electronic circuit with electronic components 1.2 electrically connected to each other via layers E and F. The electronic circuit may include, for example, an ASIC module. The electronic circuit of the scanning element 1 functions not only as an evaluation element but also as an excitation control element, controlling the excitation currents flowing through the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, and 1.1251. Thus, the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, and 1.1251 are energized by a single excitation control element. Here, the excitation lines 1.111, 1.113, 1.115, 1.121, 1.123, and 1.125 are electrically connected in series.

[0048] When the excitation lines 1.111, 1.113, 1.115, 1.121, 1.123, 1.125 are energized with the appropriate current direction, a cylindrically or tubularly oriented electromagnetic field is generated around the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251. The magnetic field lines of the resulting electromagnetic field extend around the excitation lines 1.111, 1.113, 1.115, 1.121, 1.123, 1.125, and the direction of the magnetic field lines depends in a known manner on the direction of the current in the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251. Eddy currents are induced in the conductive pitch regions 2.11, 2.21; 3.11, 3.21, respectively, resulting in a field modulation that depends on the angular position. Thus, the relative angular position can be measured by the receiving lines 1.112, 1.114, 1.122, 1.124, respectively. Pairs of receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 are arranged within the receiving lines 1.112, 1.114, 1.122, 1.124, respectively, so that they each provide signals 90° out of phase with one another, thereby enabling the direction of rotation to be determined. The signals generated by the receiving lines 1.112, 1.114, 1.122, 1.124 are further processed by part of the electronics 1.2, which forms the evaluation circuit. The signal on the first receive line 1.112 provides the greatest or finest resolution of angular position as it scans the inner pitch line 2.1 of the first scale element 2.

[0049] The first and second shielding layers 1.13, 1.14 substantially prevent the spread of adverse influences on the measurement accuracy of the two detector units 1.11, 1.12. In particular, unacceptably high levels of crosstalk signals are prevented, while excessive attenuation of the excitation field is avoided. Furthermore, electromagnetic interference of the detector units 1.11, 1.12 by the electronics 1.2 or from the outside is also prevented. [Explanation of symbols]

[0050] 1 scanning element 1.1 Printed circuit board 1.11 First detector unit 1.111 First excitation line 1.1111 Excitation conductor path 1.112 First receiving line 1.1121 first receiving conductor 1.113 Third excitation line 1.1131 excitation conductor path 1.114 Third receiving line 1.1141 Third receiving conductor 1.115 5th excitation wire 1.1151 excitation conductor track 1.116 first connecting conductor path 1.12 Second detector unit 1.121 Second excitation line 1.1211 Excitation conductor track 1.122 Second receiving line 1.1221 Second receiving conductor 1.123 Fourth excitation wire 1.1231 excitation conductor path 1.124 Fourth receiving line 1.1241 Fourth receiving conductor 1.125 6th excitation wire 1.1251 excitation conductor track 1.126 second connecting conductor 1.13 First shield layer 1.14 Second shield layer 1.15 via 1.2 Electronic Components 2 First scale element 2.1 Pitch line 2.11 Conductive Pitch Area 2.12 Non-conductive pitch areas 2.2 Pitch line 2.21 Conductive Pitch Area 2.22 Non-conductive pitch areas 3 Second Scale Element 3.1 Pitch line 3.11 Conductive Pitch Area 3.12 Non-conductive pitch areas 3.2 Pitch line 3.21 Conductive Pitch Area 3.22 Non-conductive pitch areas A. First layer B. Second layer C. Sixth Layer D. Fifth Layer E. Third layer F. Fourth Layer D1 First diameter d2 Second diameter L1 First length L2 Second length M center plane R-axis U1 First gap U2 Second gap x first direction y second direction z Third direction γ angle λ1 First period length λ2 Second period length λ3 Third period length λ4 Fourth period length

Claims

1. A scanning element (1) for an inductive position measuring device, comprising a printed circuit board (1.1), said printed circuit board (1.1) a first detector unit (1.11) having a first receiving line (1.112) and a third receiving line (1.114), a second detector unit (1.12) having a second receiving line (1.122) and a fourth receiving line (1.124), the printed circuit board (1.1) has a geometrical central plane (M) located between the detector units (1.11, 1.12), the receiving lines (1.112, 1.114, 1.122, 1.124) are arranged to circumferentially surround the axis (R), the third receiving line (1.114) extends radially outward relative to the first receiving line (1.112), and the second receiving line (1.122) extends radially outward relative to the fourth receiving line (1.124); the first receiving line (1.112) comprises a first receiving conductor (1.1121), the second receiving line (1.122) comprises a second receiving conductor (1.1221), the third receiving line (1.114) comprises a third receiving conductor (1.1141), the fourth receiving line (1.124) comprises a fourth receiving conductor (1.1241), the receiving conductors (1.1121, 1.1221, 1.1141, 1.1241) each have a periodic path; the third receiving line (1.114) has a first gap (U1) along its extension in the circumferential direction, the first gap (U1) being defined by the third receiving conductor (1.1141); the second receiving line (1.122) has a second gap (U2) along its extension in the circumferential direction, the second gap (U2) being defined by the second receiving conductor (1.1221); the first detector unit (1.11) comprises a first connecting conductor (1.116), which is electrically connected to one of the first receiving conductors (1.1121) and extends through the first gap (U1) with a radial component of direction, A scanning element, wherein the second detector unit (1.12) includes a second connecting conductor (1.126), which is electrically connected to one of the fourth receiving conductors (1.1241) and extends through the second gap (U2) with a radial direction component.

2. 2. The scanning element (1) according to claim 1, wherein the first gap (U1) is arranged circumferentially offset by an angle (γ) relative to the second gap (U2).

3. The printed circuit board (1.1) is constructed in multiple layers, The first detector unit (1.11) is arranged on a first layer (A) and a second layer (B) of the printed circuit board (1.1), 3. A scanning element (1) according to claim 1 or 2, wherein the second detector units (1.12) are arranged on a third layer (E) and a fourth layer (F) of the printed circuit board (1.1).

4. 4. A scanning element (1) as claimed in claim 3, wherein the first connecting conductor path (1.116) extends alternately between the first layer (A) and the second layer (B) of the printed circuit board (1.1) in some sections, and / or the second connecting conductor path (1.126) extends alternately between the third layer (E) and the fourth layer (F) of the printed circuit board (1.1) in some sections.

5. 3. The scanning element (1) according to claim 1 or 2, wherein the printed circuit board (1.1) includes electronic components (1.2), and the second detector unit (1.12) and at least one of the electronic components (1.2) are arranged on the same side of the printed circuit board (1.1).

6. 6. The scanning element (1) of claim 5, wherein the first detector unit (1.11), in particular the first connecting conductor path (1.116), is electrically connected to the at least one electronic component (1.2) via a via (1.15), the via (1.15) being arranged radially outside the second receiving line (1.122).

7. 3. A scanning element (1) according to claim 1 or 2, wherein the first gap (U1) extends in the circumferential direction by a first length (L1), the third receiving conductor path (1.1141) has a periodic path with a third periodic length (λ3), and L1≧1 / 8·λ3 holds.

8. the second gap (U2) extends in the circumferential direction by a second length (L2), and the second receiving conductor (1.1221) has a periodic path with a second periodic length (λ2); 3. A scanning element (1) according to claim 1 or 2, wherein L2>1 / 8·λ2 holds.

9. A scanning element (1) as described in claim 1 or 2, wherein the first receiving conductor path (1.1121) has a periodic path with a first period length (λ1), the third receiving conductor path (1.1141) has a periodic path with a third period length (λ3), and the first period length (λ1) is less than or equal to the third period length (λ3).

10. 10. A scanning element (1) as described in claim 9, wherein the second receiving conductor (1.1221) has a periodic path with a second period length (λ2), the fourth receiving conductor (1.1241) has a periodic path with a fourth period length (λ4), and the first period length (λ1) is less than or equal to the second, third, and fourth period lengths (λ2, λ3, λ4).

11. 3. A scanning element (1) according to claim 1 or 2, wherein the second receiving conductor (1.1221) has a periodic path with a second period length (λ2), the fourth receiving conductor (1.1241) has a periodic path with a fourth period length (λ4), and the second period length (λ2) is less than or equal to the fourth period length (λ4).

12. 3. A scanning element (1) according to claim 1 or 2, wherein the first detector unit (1.11) has a first excitation line (1.111) and the second detector unit (1.12) has a second excitation line (1.121).

13. 3. An inductive position measuring device comprising a scanning element (1) according to claim 1 or 2, a first scale element (2) and a second scale element (3), the scale elements (2, 3) being arranged spaced apart on either side of the printed circuit board (1.1) in a third direction (z) oriented perpendicular to the central plane.

14. 14. The inductive position measuring device of claim 13, wherein the first scale element (2) has a first diameter (D1) and the second scale element (3) has a second diameter (d2), the first diameter (D1) being larger than the second diameter (d2).

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