Scanning element and inductive position measuring mechanism including said scanning element

Abstract

To provide a scanning element for an inductive position measuring device, configured to relatively precisely work and relatively save the space.SOLUTION: A scanning element comprises a printed circuit board. The printed circuit board includes a first detection unit. The first detection unit includes a first receiving conductor path 1.1121, and the first receiving conductor path 1.1121 is disposed to go around an axis R in a circumferential direction x. A trajectory of the first receiving conductor path 1.1121 is periodically formed along a first line K1, has a first gap U1 along the extension of the first receiving conductor path 1.1121 in the circumferential direction x of the trajectory, has a first amplitude J11 within a first quadrant I or a second quadrant II of the Cartesian coordinate system, and has a second amplitude J13 within a third quadrant III or a fourth quadrant IV of a coordinate system. An origin of the coordinate system is located on the axis R and an ordinate O1 passes through the center in the circumferential direction x of the first gap U1. The second amplitude j13 is smaller than the first amplitude J11.SELECTED DRAWING: Figure 6

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 two scale elements rotatable at different speeds, and to a position measuring mechanism comprising such a scanning element. [Background technology]

[0002] Inductive position measuring mechanisms are used, for example, as angle measuring instruments for determining the angular position of machine parts that can rotate relative to one another. In inductive position measuring mechanisms, an excitation track and a receiving track are often provided, for example, in the form of conductor tracks, on a common, usually multilayer, printed circuit board, which is fixedly connected, for example, to the stator of the angle measuring instrument. A scale element is located opposite the printed circuit board, on which a graduation structure is provided and which is non-rotatably connected to the rotor of the angle measuring instrument. When a time-alternating excitation current is applied to the excitation track, a signal that depends on the angular position is generated in the receiving track during the relative rotation of the rotor and stator. This signal is then further processed in the evaluation electronics.

[0003] In particular, when driving robots, inductive position measuring mechanisms are often used as measuring devices for determining the angular position of the drive shaft and simultaneously precisely determining the angular position of the driven shaft, the movement of which is transferred to the driven shaft by a reduction gear. In this case, the angular position is measured using a scanning element which includes a printed circuit board with corresponding detection units on both sides, so that the respective angular positions can be determined by means of scale elements which are rotatably arranged on both sides of the printed circuit board.

[0004] EP 2 312 272 A2 shows, for example according to FIG. 4 of this patent document, a position measuring mechanism in which the stator is provided with receiving conductor tracks with circumferentially extending gaps. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] EP2312272A2 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem underlying the invention is to provide a scanning element for an inductive position measuring system that functions relatively precisely and is constructed in a relatively space-saving manner. [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 defined for an inductive position measuring mechanism includes a printed circuit board, the printed circuit board including a first detection unit having at least a first receiving conductor, the first receiving conductor being arranged in a circumferential direction around an axis. The path of the first receiving conductor is formed periodically along a first line. Furthermore, the periodic path of the first receiving conductor has a first gap along its extension in the circumferential direction. A Cartesian coordinate system (also called a rectangular coordinate system) is inserted to define the geometric arrangement and formation of the receiving conductor, and the Cartesian coordinate system is aligned so that its origin is on the axis and its ordinate passes through the circumferential center of the first gap. The path of the first receiving conductor has a first amplitude in a first quadrant (also called a first quarter circle) or a second quadrant of the coordinate system. In the third or fourth quadrant of the coordinate system, the track of the first receiving conductor has a second amplitude, whereby the second amplitude is smaller than the first amplitude.

[0008] In particular, the first detection unit includes a first receiving track and optionally a first excitation track, the first receiving track also including a plurality of receiving conductors (including the first receiving conductor), the first receiving track being arranged circumferentially around the axis.

[0009] A receiving conductor can run in two planes or layers of a printed circuit board, with corresponding segments or sections of one such receiving conductor being electrically coupled to a section in another layer by through vias (e.g. in the form of microvias). Due to the periodic trajectory, the receiving conductor has intersections in plan view, which are points where the receiving conductors overlap in their periodic trajectories, in that the receiving conductors run in different layers of the printed circuit board in the area of the intersections, so that undesired short circuits do not occur at the intersections.

[0010] The periodic trajectory of the first receiving conductor is formed in such a way that the receiving conductor sandwiches a surface between the intersections, which in each case extends along a line over a length corresponding to half the periodic length. Gaps are regions where such sandwiched surfaces do not exist. The amplitude can only be meaningfully defined in regions of the (in particular the first) receiving conductor where the trajectory of the (in particular the first) receiving conductor is periodic; in addition, the (in particular the second) amplitude must be greater than zero. In particular, regions of the first receiving conductor where no sandwiched surfaces exist do not have the (in particular the second) amplitude.

[0011] Accordingly, the first receiving conductor arranged on the printed circuit board so as to go around the axis in a circumferential direction does not extend circumferentially over the entire 360°, but rather over a smaller angular value due to the width of the gap.

[0012] The amplitude can be considered as the maximum distance from the wire to the receiving conductor within one period. When the path of the receiving conductor is said to have a particular amplitude within one quadrant, this means that such amplitude occurs within at least one of the period lengths.

[0013] The first line is in particular a line formed by connecting the intersections of the first receiving conductors or a line on which the intersections are located. The first line can in particular be formed circularly, in which case in particular the center point of the first line is located on the axis.

[0014] Advantageously, the first receiving conductor has a periodic path with a constant first period length (λ1) outside the first gap, so that in particular the first receiving conductor always runs in the circumferential direction with the same first period length (λ1), while the amplitude varies.

[0015] In a further embodiment of the invention, the track of the first receiving conductor has a first amplitude in both quadrant 1 and quadrant 2. Alternatively or additionally, the track of the first receiving conductor can have a second amplitude in both quadrant 3 and quadrant 4.

[0016] Advantageously, the trajectory of the first receiving conductor has a further amplitude in the third or fourth quadrant of the coordinate system, which further amplitude is smaller than the first amplitude and larger than the second amplitude.

[0017] Advantageously, the first gap extends in the circumferential direction over a first length L1, which is the same as the first periodic length (λ1) or a multiple of the first periodic length (λ1) (L1=n·λ1, where n is a natural number greater than zero). It is particularly advantageous for the first gap to extend in the circumferential direction over a first length L1, which is half the first periodic length (λ1) or a multiple of half the first periodic length (λ1) (L1=n·½·λ1, where n is a natural number greater than zero).

[0018] Advantageously, the printed circuit board contains the electronic components. In a further embodiment of the present invention, the printed circuit board includes a second detection unit having a second receiving conductor. The second receiving conductor is also arranged circumferentially around the axis and has a periodic track along a second line. The second detection unit includes, among other things, a second receiving track and optionally a second excitation track, the second receiving track also including a plurality of receiving conductors (including the second receiving conductor). The second receiving track is arranged circumferentially around the axis.

[0019] The second line may also be a line formed by connecting the intersections of the second receiving conductors or a line on which the intersections are located. The second line may be formed in a circular shape. The center point of the second line may be located on the axis.

[0020] Furthermore, the track of the second receiving conductor is configured to have a third amplitude in the first or second quadrant of the further Cartesian coordinate system and a fourth amplitude in the third or fourth quadrant of the coordinate system, the third amplitude being greater than the fourth amplitude if the origin of the further coordinate system is located on the axis and the ordinate of the further coordinate system passes through the middle of the second gap.

[0021] Advantageously, the printed circuit board has a geometrical central plane, which central plane is located between the first and second detection units. Typically, both largest (top) faces of a printed circuit board are oriented parallel to one another. A central plane is located particularly midway between and parallel to 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, particularly in the direction z oriented perpendicular to the central plane.

[0022] In an advantageous embodiment of the invention, the second detection 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 detection 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 detection unit and the electronic component.

[0023] Advantageously, the first detection unit has a third receiving track and the second detection unit has a fourth receiving track. In a further embodiment of the invention, the first detection unit has a third excitation track and the second detection unit has a fourth excitation track.

[0024] In a further embodiment of the present invention, the first excitation track and the second excitation track run along the circumferential direction. Advantageously, both the first and second receiving tracks and the first and second excitation tracks run along the circumferential direction.

[0025] Advantageously, the scanning element is formed such that the first excitation track and the second excitation track are electrically connected in series. Advantageously, the first and second excitation tracks can be energized by an excitation current, which typically has a current intensity that alternates over time (alternating current or mixed current). The excitation current can be generated by electronic components, i.e. the trajectory of the excitation current can be shaped by electronic components. Due to the physical relationship between current intensity and voltage intensity, the same considerations can of course be applied to the excitation voltage.

[0026] In a further embodiment of the invention, the signals that can be generated by the first and second receiving tracks can be further processed by electronic components that constitute, inter alia, an evaluation circuit. That is, the electronic components can be elements of various electronic circuits, i.e., assigned to different circuits, e.g., a particular electronic component can be an element of a circuit for generating an excitation current, or a further electronic component can be an element of a further circuit for evaluating or further processing the signal.

[0027] In accordance with a further aspect, the present invention also includes an inductive position measurement mechanism having a scanning element and a first scale element, the first scale element being offset and spaced apart parallel to the axis relative to the printed circuit board.

[0028] In a further embodiment of the invention, the first scale element has a graduation track which is ring-shaped and arranged concentrically with respect to the axis, the graduation track including a graduation structure which is made up of a periodic sequence of alternating conductive and non-conductive graduation areas.

[0029] Advantageously, the position measuring mechanism comprises second scale elements, which are arranged spaced apart in the direction z (orthogonal to the central plane) on either side of the printed circuit board. 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).

[0030] Additionally, the scale elements may be rotatably arranged relative to the scanning element about a common axis. Additionally, at least one of the electronic components may be arranged further away from the axis than the outer contour of the second scale element, i.e., in this case, the at least one electronic component is arranged radially outward from the second scale element.

[0031] 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 explanation of the drawings]

[0032] [Figure 1] FIG. 2 is a perspective view of a position measurement mechanism including a scanning element and first and second scale elements. [Figure 2] FIG. 2 is a plan view of a first face of a scanning element. [Figure 3] FIG. 2 is a detailed plan view of a first face of the scanning element. [Figure 4] FIG. 10 is a plan view of a second face of the scanning element. [Figure 5] FIG. 10 is a detailed plan view of the second face of the scanning element. [Figure 6] 3 is a schematic plan view of a first receiving conductor on a first face of a scanning element; FIG. [Figure 7] 4 is a schematic plan view of a second receiving conductor on a second face of the scanning element; FIG. [Figure 8] FIG. 2 is a plan view of a first scale element. [Figure 9] FIG. 10 is a plan view of a second scale element. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be described with reference to FIG. 1 based on a position measurement mechanism. This position measurement mechanism has a scanning element 1 that can be used to capture the angular position of a first scale element 2 and a second scale element 3. Both scale elements 2, 3 are arranged rotatably relative to the scanning element 1 around an axis R. Such a position measurement mechanism can be used, for example, in a drive mechanism for a robot. In this case, the second scale element 3 is non-rotatably connected to, for example, a drive shaft of a motor. The drive shaft is also connected to a reduction gear, which has a driven shaft that rotates the first scale element 2. In this way, the second scale element 3 can determine an angular position, for example, for commutating a motor, and the first scale element 2 can determine a relatively high-precision angular position for positioning a robot.

[0034] The scanning element 1 includes a printed circuit board 1.1 having several layers and electronic components 1.2 mounted on the printed circuit board 1.1. The scanning element 1 is used to scan a first scale element 2 and simultaneously scan a second scale element 3. In the illustrated exemplary embodiment, the electronic components 1.2 are mounted only on the second side. However, instead of or in addition to this, the first side of the printed circuit board 1.1 may also be equipped with electronic components.

[0035] To determine the angle information, a first detection unit 1.11 is arranged on a first side of the printed circuit board 1.1 and a second detection unit 1.12 is arranged on a second side of the printed circuit board 1.1. In Figure 1, only the structure of the second detection unit 1.12 that is present on the outer layer of the printed circuit board 1.1 is schematically visible.

[0036] 2 and 3 (FIG. 3 is an enlarged detailed view of the first detection unit 1.11 according to FIG. 2) show, inter alia, the structures of the first detection unit 1.11 present in the outer layers of the printed circuit board 1.1 and in the inner layers of the printed circuit board 1.1. The first detection unit 1.11 includes a first excitation track 1.111, a first receiving track 1.112, a third excitation track 1.113, a third receiving track 1.114, and a fifth excitation track 1.115. The first receiving track 1.112 includes a first receiving conductor 1.1121.

[0037] Figures 4 and 5 show the other side of the printed circuit board 1.1, thus revealing the second detection unit 1.12. Figure 5 shows an enlarged view of the second detection unit 1.12 in detail. Figures 4 and 5 show, inter alia, the structure of the second detection unit 1.12 present in the outer layer of the printed circuit board 1.1 and in adjacent inner layers of the printed circuit board 1.1. The second detection unit 1.12 includes a second excitation track 1.121, a second receiving track 1.122, a fourth excitation track 1.123, a fourth receiving track 1.124, and a sixth excitation track 1.125. The second receiving track 1.122 includes a second receiving conductor 1.1221.

[0038] Geometrically, a so-called central plane M (Fig. 1) can be defined for the printed circuit board 1.1, which is parallel to the first and second faces of the printed circuit board 1.1 and is located midway between them. An axis R runs perpendicular to the central plane M. The printed circuit board 1.1 is shaped in such a way that the geometric central plane M lies between the first and second detection units 1.11 and 1.12.

[0039] The excitation tracks 1.111, 1.113, 1.115 of the first detection unit 1.11 contain excitation conductor paths 1.1111, 1.1131, 1.1151, and the excitation tracks 1.121, 1.123, 1.125 of the second detection unit 1.12 contain excitation conductor paths 1.1211, 1.1231, 1.1251.

[0040] The excitation tracks 1.111, 1.113, 1.115 of the first detection unit 1.11 surround the first receiving track 1.112 or the third receiving track 1.114. The excitation tracks 1.121, 1.123, 1.125 of the second detection unit 1.12 surround the second receiving track 1.122 or the fourth receiving track 1.124. The excitation tracks 1.111, 1.113, 1.115, 1.121, 1.123, 1.125 as well as the receiving tracks 1.112, 1.114, 1.122, 1.124 run in the circumferential direction x.

[0041] In the exemplary embodiment shown, each of the receiver tracks 1.112, 1.114, 1.122, 1.124 includes a receiver conductor 1.1121, 1.1141, 1.1221, 1.1241, respectively, which are arranged offset in the circumferential direction x and thus can provide four phase-shifted signals accordingly. In the figure, the receiver conductors 1.1121, 1.1141, 1.1221, 1.1241 belonging to one and the same receiver track 1.112, 1.114, 1.122, 1.124 are labeled with a single reference number. This means that, for example, all receiver conductors 1.1121 of the first receiver track 1.112 are labeled with a single reference number. In addition, the first receiving conductor 1.1121 of the first detection unit 1.11 is connected to vias and runs on different layers of the printed circuit board 1.1, thus avoiding undesired short circuits at the intersections N1, N2 (see Figures 6 and 7). The same applies to the receiving conductors 1.1221, 1.1241 of the second detection unit 1.12. Although, strictly speaking, the first and second receiving conductors 1.1121, 1.1221 each consist of a number of conductor strips arranged side by side and distributed over two planes or layers, in the following, such structures will be referred to collectively as a single receiving conductor 1.1221, 1.1241.

[0042] The first and second receiving conductors 1.1121, 1.1221 have a spatially periodic trajectory along a circular first line K1 or a circular second line K2 (FIGS. 6, 7), which trajectory is substantially sinusoidal or sinusoidally shaped. The lines K1, K2 are, so to speak, circular abscissas of the sinusoidal trajectories of the receiving conductors 1.1121, 1.1221. The centers of the circular lines K1, K2 are otherwise located on the axis R. The first lines K1 can also be considered as connecting lines of adjacent first intersections N1. Similarly, the second lines K2 can be defined as connecting lines of adjacent second intersections N2. All first intersections N1 are located on the circular first line K1, and all second intersections N2 are located on the circular second line K2.

[0043] The receiving conductors 1.1121 of the first receiving track 1.112 have a period length λ1 (FIG. 3), while the receiving conductors 1.1221 of the second receiving track 1.122 have a period length λ2 (FIG. 5). In the exemplary embodiment shown, adjacent receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 in one receiving track 1.112, 1.114, 1.122, 1.124 are offset from each other by 1 / 8 of a complete sine wave period (π / 4 or 45° along the circumferential direction x), so that these receiving conductors can generate signals with corresponding phase shifts. The receiving conductors 1.1121, 1.1141, 1.1221, 1.1241 are electrically connected so that they provide 0° and 90° signals on the one hand and 45° and 135° signals on the other hand. A first position signal can be determined from the 0° and 90° signals, and a second position signal that is redundant to the first position signal can be determined from the 45° and 135° signals.

[0044] FIG. 6 shows a simplified plan view of the first receiving conductor 1.1121 of the first receiving track 1.112, in which, for clarity, the phase-shifted receiving conductors of the first receiving track 1.112 have been omitted from the drawing. According to FIG. 6, the path of the first receiving conductor 1.1121 belonging to one phase, i.e., providing a signal of one phase, has a gap U1 along the extension of the first receiving conductor 1.1121 in the circumferential direction x. The area of the first gap U1 is thus delimited by the first receiving conductor 1.1121 of one phase. In the area of the first gap U1, the periodically running first receiving conductor 1.1121 of that phase is not arranged.

[0045] As shown in FIG. 6, the receiving conductor 1.1121 belonging to one and the same phase can be divided into 15 equal-sized sectors 1a-1o, each spanning a central angle of 24°, corresponding to the first periodic length λ1. In the exemplary embodiment shown in FIG. 6, the first gap U1 extends over a first angular length L1, which corresponds to the first periodic length λ1 or 24°, so that L1 = λ1 = 24°. To explain the geometrical arrangement, a Cartesian coordinate system can first be inserted, with its origin on the axis R or on the center point of the first line K1, and with the ordinate O1 passing through the middle of the first gap U1. This means that the ordinate O1 is equally spaced in the circumferential direction x from the ends of the periodically running first receiving conductor 1.1121. This coordinate system has four quadrants (or quadrants) I-IV according to the usual division. The path of the first receiving conductor 1.1121 has different amplitudes J11, J12, J13 along the circumferential direction x, i.e., in the region of maximum deflection, there are different distances between the first line K1 and the sinusoidally running receiving conductor 1.1121. In the presented exemplary embodiment, the following amplitudes J11, J12, J13 can be determined for each sector 1a-1o: Amplitude J11 (100%): Sectors 1a, 1b, 1c, 1d, 1f, 1g, 1h, 1i, 1j, 1o Amplitude J12 (80%): Sector 1k, 1n Amplitude J13 (70%): Sector 1l, 1m No amplitude: Sector 1e (area of the first gap U1) The path of the first receiving conductor 1.1121 therefore has a first amplitude J11 in the first quadrant I and in the second quadrant II, and further has a second amplitude J13 in the third quadrant III and in the fourth quadrant IV, which is smaller than the first amplitude J11.

[0046] In addition, the trajectory of the first receiving conductor 1.1121 has a further amplitude J12 in the third quadrant III and in the fourth quadrant IV of the coordinate system, which amplitude J12 is smaller than the first amplitude J11 and larger than the second amplitude J13, so that J11>J12>J13 applies.

[0047] FIG. 7 shows a simplified plan view of the second receiving conductor 1.1221 of the second receiving track 1.122, where again, as in FIG. 6, the phase-shifted receiving conductor thereto has been omitted.

[0048] According to FIG. 7, the path of the second receiving conductors 1.1221 belonging to one phase has a second gap U2 along its extension in the circumferential direction x. The area of the second gap U2 is thus defined by the second receiving conductors 1.1221. In the area of the second gap U2, the periodically running second receiving conductors 1.1221 of the phase in question are not arranged. As shown in FIG. 7, the receiving conductors 1.1221 belonging to one phase can be divided into 16 equal-sized sectors 2a-2p according to the second periodic length λ2, each of which spans a central angle of 22.5°. In the exemplary embodiment shown according to FIG. 7, the second gap U2 extends over a second angular length L2, which corresponds to twice the second periodic length λ2, i.e., 45°. Accordingly, L2 = 2·λ2 = 2·22.5° applies. Within the second receiving track 1.122, the path of the second receiving conductor 1.1221 also has different amplitudes J21, J22, J23, J24 along the circumferential direction x. In the presented exemplary embodiment, the following amplitudes J21, J22, J23, J24 can be determined for each sector 2a-2p: Amplitude J21 (100%): Sectors 2a, 2b, 2c, 2f, 2g, 2h, 2i, 2p Amplitude J22 (80%): Sector 2j, 2o Amplitude J23 (65%): Sector 2k, 2n Amplitude J24 (50%): Sector 2l, 2m No amplitude: sectors 2d and 2e (in the area of the second gap U2) The path of the second receiving conductor 1.1221 therefore has a third amplitude J21 in the first quadrant I and in the second quadrant II, and further has a fourth amplitude J24 in the third quadrant III and in the fourth quadrant IV, which is smaller than the third amplitude J21.

[0049] The path of the second receiving conductor 1.1221 is designed so that the transition from the maximum third amplitude J21 to the minimum fourth amplitude J24 occurs gradually. Accordingly, the path of the second receiving conductor 1.1221 has two further amplitudes J22, J23 in the third quadrant III and in the fourth quadrant IV of the coordinate system, which further amplitudes J22, J23 are smaller than the third amplitude J21 and larger than the fourth amplitude J24. Therefore, J21>J22>J23>J24 applies.

[0050] Additionally, the printed circuit board 1.1 has through-hole vias 1.15, 1.16 (FIGS. 3 and 5). The printed circuit board 1.1 is configured so that the through-hole vias 1.15, 1.16 are located both in the first gap U1 and in the second gap U2. The through-hole via 1.15 electrically couples the first receiving conductor 1.1121 of the first receiving track 1.112 to the electronic component 1.2 located on the other side of the central plane M. This special design of the paths of the first and second receiving conductors 1.1121, 1.1221 with the gaps U1, U2 allows for a particularly space-saving design of the printed circuit board 1.1. The signal loss caused by the gaps U1, U2 can be compensated for by the inventive design of the paths of the first and second receiving conductors 1.1121, 1.1221, ultimately resulting in a space-saving design and accurate angle measurement.

[0051] Figure 8 shows a plan view of the first scale element 2. Figure 9 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 greater than the second diameter d2 (D1>d2).

[0052] Each of the scale elements 2, 3 comprises a base made of epoxy resin in the illustrated exemplary embodiment, on which two graduation tracks 2.1, 2.2; 3.1, 3.2 are arranged. The graduation tracks 2.1, 2.2; 3.1, 3.2 are ring-shaped and arranged on the base concentrically with respect to the axis R, with different diameters. The graduation tracks 2.1, 2.2; 3.1, 3.2 each comprise a graduation structure consisting of a periodic sequence of alternating conductive graduation fields 2.11, 2.21; 3.11, 3.21 and non-conductive graduation fields 2.12, 2.22; 3.12, 3.22. In the illustrated example, copper is applied to the base as the material for the conductive graduation fields 2.11, 2.21; 3.11, 3.21. In contrast, the substrate was not coated within the non-conductive graduation areas 2.12, 2.22; 3.12, 3.22. The arrangement with two graduation tracks 2.1, 2.2; 3.1, 3.2 allows the angular position of each of the scale elements 2, 3 to be determined absolutely. The outermost graduation track 2.2 of the first scale element 2 has the greatest number of graduation areas 2.21, 2.22 along its circumference, and therefore the graduation areas 2.21, 2.22 allow the greatest possible resolution for measuring the angular position.

[0053] 1, the scanning element 1 and the scale elements 2, 3 face each other with an axial distance or gap therebetween, so that when the scale elements 2, 3 and the scanning element 1 rotate relative to each other, signals that depend on the respective angular position can be generated by inductive effects in the receiving conductors 1.1121, 1.1141, 1.1221, 1.1241. The generation of such signals is prerequisite for the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251 to generate a time-varying electromagnetic excitation field in the region of the respective scanned graduation structure. In the illustrated exemplary embodiment, the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251 are configured as a number of single conductors that are traversed by a current in parallel planes. The scanning element 1 has an electronic circuit with electronic components 1.2. The electronic circuit may include, for example, an ASIC chip. This electronic circuit of the scanning element 1 functions not only as an evaluation element but also as an excitation control element, under the control of which an excitation current is generated or generated, which then flows through the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, and 1.1251. The excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, and 1.1251 are therefore energized by one and the same excitation control element. In this regard, the first excitation track 1.111 and the second excitation track 1.121 are electrically connected in series.

[0054] When the excitation tracks 1.111, 1.113, 1.115, 1.121, 1.123, 1.125 are energized, a tubular or cylindrically oriented electromagnetic field is generated around the excitation conductors 1.1111, 1.1131, 1.1151, 1.1211, 1.1231, 1.1251. The field lines of this resulting field run around the excitation tracks 1.111, 1.113, 1.115, 1.121, 1.123, 1.125, and the direction of the field lines depends, as is known, 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 area of the conductive graduation fields 2.11, 2.21; 3.11, 3.21, resulting in a field modulation that depends on the angular position. The relative angular position can be measured by the receiving tracks 1.112, 1.114, 1.122, 1.124, respectively. The receiving conductor pairs 1.1121, 1.1141, 1.1221, 1.1241 are arranged in the receiving tracks 1.112, 1.114, 1.122, 1.124 so that each pair of receiving conductors provides a signal that is phase-shifted by 90°, which also allows the direction of rotation to be determined. The signals generated by the receiving tracks 1.112, 1.114, 1.122, 1.124 are further processed by several electronic components 1.2, which form an evaluation circuit.

[0055] For high measurement accuracy combined with relatively generous mounting tolerances, it is advantageous to perform so-called full-circumference scanning. In full-circumference scanning, the scale elements 2, 3 are scanned in their entirety at each instant, i.e., practically over the entire circumference. This has the advantage of correcting any wobble errors or eccentricities that may occur in the measurement result. This novel scanning element 1 allows for accurate measurements even if the receiving conductors 1.1121, 1.1221 have gaps U1, U2. [Explanation of symbols]

[0056] 1 scanning element 1.1 Printed circuit board 1.11 First detection unit 1.1121 first receiving conductor 1.12 Secondary detection unit 1.1221 Second receiving conductor 1.2 Electronic Components 2 First scale element 2.1 Scale Track 2.11 Conductive Graduation Area 2.12 Non-conductive scale area 3 Secondary scale element I Quadrant 1 II Quadrant 2 III Quadrant 3 IV Quadrant 4 D1 First diameter d2 Second diameter J11 First Amplitude J12 Further Amplitude J13 Second Amplitude J21 Third Amplitude J22, J23 Further Amplitude J24 4th Amplitude K1 First Line K2 Second Line L1 First length L2 Second length M center plane O1 ordinate O2 ordinate R-axis U1 First gap U2 Second gap x circumferential direction z direction oriented perpendicular to the central plane λ1 First period length λ2 Second period length

Claims

1. A scanning element (1) for an inductive position measuring mechanism, the scanning element (1) comprising a printed circuit board (1.1), the printed circuit board (1.1) comprising a first detection unit (1.11), the first detection unit (1.11) comprising a first receiving conductor (1.1121), the first receiving conductor (1.1121) being arranged in a circumferential direction (x) around an axis (R), the axis (R) being perpendicular to the printed circuit board (1.1), The track of the first receiving conductor (1.1121) is are periodically formed along the first line (K1), - a first gap (U1) along the extension of the first receiving conductor (1.1121) in the circumferential direction (x) of the track, - in the first quadrant (I) or in the second quadrant (II) of the Cartesian coordinate system, it has a first amplitude (J11); - in the third quadrant (III) or in the fourth quadrant (IV) of said coordinate system, it has a second amplitude (J13), The origin of the coordinate system is located on the axis (R), and the ordinate (O1) passes through the center of the first gap (U1) in the circumferential direction (x), and The scanning element (1), wherein the second amplitude (J13) is less than the first amplitude (J11).

2. A scanning element (1) according to claim 1, A scanning element (1), wherein said first line (K1) is circularly shaped.

3. A scanning element (1) according to claim 1 or 2, A scanning element (1), wherein the first receiving conductor (1.1121) has a periodic orbit with a constant first period length (λ1).

4. A scanning element (1) according to any one of claims 1 to 3, A scanning element (1), wherein the trajectory of the first receiving conductor (1.1121) has the first amplitude (J11) in the first quadrant (I) and in the second quadrant (II).

5. A scanning element (1) according to claim 4, A scanning element (1), wherein the trajectory of the first receiving conductor (1.1121) further has the second amplitude (J13) in the third quadrant (III) and in the fourth quadrant (IV).

6. A scanning element (1) according to any one of claims 1 to 5, A scanning element (1), wherein the trajectory of the first receiving conductor path (1.1121) has a further amplitude (J12) in the third quadrant (III) or the fourth quadrant (IV) of the coordinate system, the further amplitude (J12) being smaller than the first amplitude (J11) and larger than the second amplitude (J13).

7. A scanning element (1) according to claim 3, A scanning element (1), wherein the first gap (U1) extends in the circumferential direction (x) over a first length (L1), the first length (L1) being equal to half the first periodic length (λ1) or a multiple of half the first periodic length, i.e. L1=n.1 / 2.λ1, where n is a natural number greater than zero.

8. A scanning element (1) according to any one of claims 1 to 7, A scanning element (1), wherein said printed circuit board (1.1) contains electronic components (1.2).

9. A scanning element (1) according to any one of claims 1 to 8, The printed circuit board (1.1) includes a second detection unit (1.12), the second detection unit (1.12) has a second receiving conductor (1.1221), and the second receiving conductor (1.1221) is arranged around the axis (R) in a circumferential direction (x), The track of the second receiving conductor (1.1221) is - periodically formed along the second line (K2), - a second gap (U2) along the extension of the second receiving conductor (1.1221) in the circumferential direction (x) of the track, - in the first quadrant (I) or in the second quadrant (II) of the further Cartesian coordinate system, it has a third amplitude (J21); - in the third quadrant (III) or in the fourth quadrant (IV) of said further coordinate system, it has a fourth amplitude (J24), the origin of the further coordinate system is located on the axis (R) and the ordinate (O2) of the further coordinate system passes through the middle of the second gap (U2); and The fourth amplitude (J24) is less than the third amplitude (J21).

10. A scanning element (1) according to claim 9, A scanning element (1), wherein the second receiving conductor (1.1221) has a periodic orbit with a constant second periodic length (λ2), and the second gap (U2) extends over a second length (L2) in the circumferential direction (x), the second length (L2) being half the size of the second periodic length (λ2) or equal to a multiple of half the second periodic length, i.e., L2 = n ½ λ2, where n is a natural number greater than zero.

11. A scanning element (1) according to any one of claims 1 to 10, The scanning element (1) comprises a printed circuit board (1.1) including a second detection unit (1.12), the second detection unit (1.12) including a second receiving conductor (1.1221), the second receiving conductor (1.1221) being arranged to wrap around the axis (R) in a circumferential direction (x), the printed circuit board (1.1) having a geometric center plane (M), the center plane (M) being located between the first detection unit (1.11) and the second detection unit (1.12).

12. 12. An inductive position measuring mechanism comprising a scanning element (1) and a first scale element (2) according to claim 11, wherein the first scale element (2) is arranged parallel to and offset from the printed circuit board (1.1) along the axis (R).

13. 13. The inductive position measurement mechanism according to claim 12, 1. An inductive position measuring system, comprising: a first scale element (2) having a graduation track (2.1), the graduation track (2.1) being ring-shaped and arranged concentrically with respect to the axis (R), the graduation track (2.1) including a graduation structure consisting of a periodic sequence of alternating conductive and non-conductive graduation areas (2.11)

14. 14. An inductive position measuring mechanism according to claim 12 or 13, The position measuring mechanism has a second scale element (3), and the first scale element (2) and the second scale element (3) are arranged on both sides of the printed circuit board (1.1) and are connected to the Inductive position measuring mechanisms spaced apart in a direction (z) oriented orthogonal to the central plane.

15. 15. The inductive position measurement mechanism according to claim 14, An inductive position measuring mechanism, wherein the first scale element (2) has a first diameter (D1), and the second scale element (3) has a second diameter (d2), and the first diameter (D1) is larger than the second diameter (d2).

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