Secondary coil assembly for inductive encoder system and inductive encoder system

Abstract

The secondary coil assembly (15) of the inductive encoder system (10) having a plurality of secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) is arranged on a conductor support without crossing each secondary coil (16, 16a, 18, 18a, 20, 20a, 22, 22a). The inductive encoder system (10) includes at least one primary coil (12, 12a, 12b) having a modulation region (14), and at least one receiver coil (42) having at least one receiver line set (44a, 44b, 44c, 44d) and the above secondary coil assembly (15), and the secondary coil assembly (15) is arranged in the modulation region (14).

Description

[Technical Field]

[0001] The present invention relates to a secondary coil assembly for an inductive encoder system and an inductive encoder system. [Background technology]

[0002] Due to their robustness against environmental influences, inductive encoder systems are used in a wide variety of applications. They can in particular be configured as rotary encoders or length measuring systems.

[0003] Essentially, an inductive encoder system is constructed so that a primary coil generates a magnetic field that induces a current in one or more secondary coils. The presence of a conductive target changes the voltage induced in the secondary coils, allowing the position of the target relative to the secondary coils to be determined.

[0004] Preferably, the structure of the inductive encoder system is realized on a printed circuit board, and the coil is attached to the printed circuit board using conductor tracks. In order to obtain a sine wave signal suitable for measuring distance or angle, the coil shape of the secondary coil in particular must be designed accordingly. For example, Patent Document 1 discloses an inductive rotary encoder in which the coil shape of the secondary coil is formed in a sine wave and a cosine wave shape. The resulting sine wave and cosine wave profiles of the measurement signal obtained from the secondary coil allow the linear position value of the target to be calculated over a certain period of time using an arctangent function. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE 10320990 A1 Summary of the Invention [Problem to be solved by the invention]

[0006] A drawback of the prior art is that conductor tracks, especially secondary coil conductor tracks, cross each other in modulation regions that are important for signal generation, making it necessary to use through holes. Connections in conductor supports are typically called through holes, which establish electrical contact between conductor tracks located on different conductor support levels. When two conductor tracks cross each other, one of the conductor tracks in the crossing region is typically transferred to another conductor support level, so that despite the crossing, no conductive contact is formed between the associated conductor tracks. Therefore, two through holes are typically provided at each crossing.

[0007] Through holes typically require a circular surface with a diameter of approximately 0.3 mm and must be at least 0.1 mm from any conductor tracks passing by them, which makes high-resolution encoder systems and the very small periods required for them unrealizable.

[0008] Furthermore, the large number of required through-holes precludes manufacturing techniques that allow for smaller period lengths but in which the through-holes are difficult to realize. Manufacturing encoder systems using such manufacturing techniques is not economically feasible. An example is sputtering conductor tracks onto glass or plastic with a conductor track thickness of a few micrometers. This allows, in principle, period lengths in the 100 μm range to be realized.

[0009] Furthermore, the through-holes arranged in the modulation area generate harmonics in the measurement signal obtained from the secondary coil, which has a negative effect on the quality of the measurement signal, in particular on the linearity of the arctangent calculated from the sine and cosine signals and therefore on the accuracy of the measurement result.

[0010] The present invention is therefore based on the object of providing a secondary coil assembly for an inductive encoder system which can be manufactured flexibly and which improves the quality of the measurement results, so that a high resolution can be achieved. Another object of the present invention is to provide a corresponding inductive encoder system. [Means for solving the problem]

[0011] The above object is achieved according to the invention by a secondary coil assembly of an inductive encoder system having the features of claim 1 and by an inductive encoder system having the features of claim 7 .

[0012] Advantageous embodiments and developments of the invention are set forth in the dependent claims. The secondary coil assembly of the inductive encoder system according to the present invention includes a plurality of secondary coils, each having a secondary coil conductor track, which is arranged on the wire support without crossing. The conductor track on which the secondary coil is formed is preferably referred to as the secondary coil conductor track. Connection conductor tracks with which the secondary coil conductor tracks contact, for example for coupling to a circuit, are preferably not considered part of the secondary coil conductor track. The secondary coils are preferably arranged such that the secondary coil conductor tracks do not cross each other when viewed from above in the direction of the secondary coil axis. The non-crossing arrangement of the secondary coil conductor tracks makes it possible to provide a secondary coil assembly in which the secondary coil conductor tracks do not have through holes, which reduces manufacturing costs, among other things. Furthermore, it allows for a reduced spacing between the individual conductor tracks, which in turn increases the resolution of the encoder system including the secondary coil assembly. Furthermore, it improves the quality of the measurement signal obtained from the secondary coil. The wire support can be formed, for example, by a printed circuit board or a glass plate. In particular, if the wire support is formed by a glass plate, the conductor tracks can be sputtered onto it.

[0013] Preferably, each secondary coil has a secondary coil surface including a secondary coil contour, which corresponds to a contour having a surface included between a sine function and a cosine function at an interval of 45° to 225°. This allows for a secondary coil contour with a typical wave form, hereinafter referred to as a sine-cosine difference form. In particular, using such a secondary coil allows for good reproduction of the characteristics of a conventional secondary coil assembly.

[0014] Particularly preferably, the secondary coil assembly has an assembly contour that at least partially corresponds to a contour having a surface formed by a plurality of adjacently arranged sine-cosine difference surfaces. In this case, the contour of the surface that is preferably covered by the entire secondary coil assembly is preferably referred to as the assembly contour. With such an arrangement, the secondary coil assembly can be used to generate measurement signals with a sinusoidal or cosine profile.

[0015] In a preferred embodiment of the present invention, the secondary coil assembly is arranged linearly, circularly, or toroidally. A linear arrangement can be used to realize, in particular, a length measurement system. A circular or toroidal arrangement of the secondary coil assembly is preferably used for a rotary encoder, i.e., in particular, an angle measurement system. In the case of a circular or toroidal arrangement of the secondary coil assembly, the secondary coil contour or assembly contour is preferably superimposed on a circle, which results in a typical flower-shaped assembly contour.

[0016] Preferably, the secondary coils are arranged adjacent to one another in the longitudinal direction of the secondary coil assembly. The adjacent arrangement is preferably realized so that two adjacent secondary coils are electrically insulated from one another. The longitudinal direction is preferably formed by the direction in which the target whose position is to be determined is intended to move relative to the secondary coil assembly. In particular, in the case of a circular or annular secondary coil assembly, the longitudinal direction can be formed arcuately according to the direction of a corresponding arc.

[0017] When the secondary coils are formed in a sine-cosine differential shape, they are preferably arranged adjacent to one another so that there is a 90° phase shift between the individual secondary coils. Thus, the secondary coil assembly can have a repeating secondary coil set, particularly four secondary coils. If the first secondary coil is designated as a positive sine coil according to the contour line defining its upper boundary, the second secondary coil adjacent to its right side can be designated as a positive cosine coil. This is followed by a negative sine coil as the third secondary coil, and a negative cosine coil as the fourth secondary coil. Preferably, the negative cosine coil is also followed by a positive sine coil of another secondary coil set.

[0018] In one development of the invention, the secondary coils are arranged in a plurality of blocks arranged parallel to one another in the longitudinal direction. In particular, this allows the secondary coils to be arranged offset from one another in the longitudinal direction. This allows the number of secondary coils per unit length to be increased in the longitudinal direction. This allows the accuracy of the encoder system incorporating the secondary coil assembly to be improved.

[0019] Preferably, the wire support has at least one wire support level, and adjacent secondary coils can be arranged on the same wire support level or on different wire support levels. By arranging the secondary coils on the same wire support level, the complexity of the wire support, and therefore particularly the manufacturing effort, can be reduced. By arranging the secondary coils on different wire support levels, adjacent secondary coils can be arranged without conductive contact and without longitudinal offset.

[0020] The inductive encoder system according to the present invention comprises at least one primary coil having a modulation area, at least one receiver track having at least one receiver line set and the aforementioned secondary coil assembly, the secondary coil assembly being arranged within the modulation area. Preferably, the area surrounded by the at least one primary coil is referred to as the modulation area. Preferably, a primary current, particularly preferably configured as an alternating current, flows through the at least one primary coil. This allows for the induction of a voltage in the secondary coil, particularly in the modulation area. This allows for the induction of a voltage in the at least one secondary coil to be influenced by placing a conductive target above at least one of the secondary coils.

[0021] The encoder system can have at least one secondary coil set consisting of multiple secondary coils, and the secondary coils of the at least one secondary coil set can be contacted in various ways with at least one receiving wire set. The contacting of the secondary coils to the at least one receiving wire set can be achieved using connecting conductor tracks. Preferably, a receiving circuit is formed by the receiving wire set, the secondary coils contacted thereto, and, if necessary, the connecting conductor tracks used for the respective contacting. Particularly preferably, the secondary coils contacted by the same receiving wire set have different flow directions. This allows the position of the target to be absolutely determined in the area of ​​at least one secondary coil set. Preferably, the different flow directions are achieved by the secondary coils contacted by the same receiving wire set having different polarities.

[0022] In a preferred embodiment of the present invention, at least one receiving coil has a first receiving wire set and a second receiving wire set, and at least one secondary coil set has a first secondary coil, a second secondary coil, a third secondary coil, and a fourth secondary coil, the first secondary coil and the third secondary coil being in contact with the first receiving wire set, and the second secondary coil and the fourth secondary coil being in contact with the second receiving wire set. Particularly preferably, the first to fourth secondary coils are arranged adjacent to each other in ascending order.

[0023] In particular, if no target is located above the secondary coil assembly, the voltages induced in the first and third secondary coils can be at least approximately the same. Preferably, the same applies to the voltages induced in the second and fourth secondary coils. Due to the different flow directions of the secondary coils contacted by the same receiver wire set, at least little current preferably flows in the respective receiver circuits unless there is a target above the secondary coil assembly. If a target is located at least partially above one of the secondary coils, the voltage induced in this secondary coil can be different from that of the other secondary coils located in the same receiver circuit, thereby allowing current to flow in the corresponding receiver circuit. Preferably, the target is shaped so as to completely cover at most one of the secondary coils. By arranging secondary coils that are not directly adjacent to each other in the same receiver circuit, the resolution of the encoder system can be increased.

[0024] When the encoder system has multiple consecutive secondary coil assemblies, the target is preferably formed to have multiple target elements. The target elements are preferably spaced apart from one another so as to cover corresponding secondary coils of two consecutive secondary coil assemblies. Thus, the target can be formed as a grid, allowing the targets to be positioned simultaneously above corresponding secondary coils.

[0025] In another development of the invention, the encoder system has at least one receiver track, a third set of receiver lines, and a fourth set of receiver lines. Furthermore, the at least one secondary coil set can have a fifth, a sixth, a seventh, and an eighth secondary coil, the fifth and seventh secondary coils being contacted to the third set of receiver lines, and the sixth and eighth secondary coils being contacted to the fourth set of receiver lines. Thereby, the area of ​​the secondary coil sets, and thus preferably the area in which the position of the target can be absolutely determined, can be made particularly large and / or have a particularly high density of secondary coils, which can increase the resolution of the encoder system.

[0026] The present invention may be configured such that the first and third receiving wire sets are in conductive contact with each other, and the second and fourth receiving wire sets are in conductive contact with each other, so that when using the encoder system, it may be sufficient to connect two receiving wire sets to an evaluation unit. Preferably, the first and third receiving wire sets, and the second and fourth receiving wire sets, are in contact with each other so that adjacent secondary coils have different flow directions.

[0027] Preferably, the secondary coils contacted by the same set of receiving wires are arranged in different blocks with a longitudinal offset, which in particular allows for an increased resolution of the encoder system with the same coil dimensions, in which case the offset is preferably between half and twice the longitudinal dimension of the secondary coils.

[0028] In one development of the invention, the inductive encoder system has a first receiving track and a second receiving track, where the first receiving track has multiple secondary coil sets and the second receiving track has exactly one secondary coil set. In this case, the first receiving track and the second receiving track are preferably arranged side by side in the longitudinal direction. The first receiving track allows the position of the target to be determined with a relatively high degree of accuracy. The second receiving track allows the position of the target to be determined absolutely over the entire length of the encoder system. This allows the position of the target to be determined absolutely over the entire length of the encoder system with a relatively high degree of accuracy.

[0029] Particularly preferably, the at least one primary coil is disposed on a first wire support level and the secondary coil assembly is disposed on a second wire support level. Furthermore, the at least one receiver wire set can be disposed on the second wire support. In particular, if the at least one receiver wire set is disposed outside the modulation area, the secondary coil can be contacted to the at least one receiver wire set without the need for through holes.

[0030] At least one primary coil of the inductive encoder system can be formed in a toroidal shape, thereby forming a circular modulation region. Preferably, when the secondary coil assembly is arranged in a circular or toroidal shape, at least one primary coil is formed in a toroidal shape. When the inductive encoder system is formed as a rotary encoder, at least one primary coil is preferably formed in a toroidal shape.

[0031] In one development of the invention, the modulation region is formed in the shape of a ring having an outer diameter and an inner diameter, the outer diameter being defined by the first primary coil and the inner diameter being defined by the second primary coil. This allows the electromagnetic field of the modulation region to be more concentrated and uniform, thereby improving the quality of the measurement signal acquired by the receiving coil in particular. This configuration of the inductive encoder system can be advantageous in particular when the diameters of the primary coil and secondary coil assemblies are large.

[0032] By forming the current direction in the first primary coil opposite to the current direction in the second primary coil, the concentration and uniformity of the electromagnetic field in the modulation area can be further increased. An embodiment of the present invention will be described with reference to the following drawings. [Brief explanation of the drawings]

[0033] [Figure 1] 1 illustrates an exemplary embodiment of a prior art inductive encoder system. [Figure 2] 1 shows a schematic diagram of a secondary coil assembly with a sine-cosine differential geometry. [Figure 3] FIG. 1 shows a schematic diagram of a first exemplary embodiment of an inductive encoder system having a linear secondary coil assembly. [Figure 4] FIG. 1 shows a schematic diagram of a second exemplary embodiment of an inductive encoder system having a toroidal secondary coil assembly. [Figure 5] FIG. 10 shows a schematic diagram of a portion of a third exemplary embodiment of an inductive encoder system having a toroidal secondary coil assembly and a toroidal modulation region. [Figure 6] FIG. 10 shows a schematic diagram of a fourth exemplary embodiment of an inductive encoder system. [Figure 6a] 7 shows a schematic diagram of a first portion of the exemplary embodiment shown in FIG. 6. [Figure 6b] 7 shows a schematic diagram of a first portion of the exemplary embodiment shown in FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0034] 1 to 6b show various exemplary embodiments. For clarity, reference symbols are not used in all figures. The same reference symbols are used for the same and functionally identical parts.

[0035] FIG. 1 shows a prior art inductive encoder system 110 with a circular primary coil 112 having a circular modulation region 114. Within the modulation region 114, a secondary coil assembly 115 is arranged in a circular configuration, including a first secondary coil 116, a second secondary coil 118, a third secondary coil 120, and a fourth secondary coil 122. Each of the secondary coils 116, 118, 120, and 122 has a secondary coil conductor track 123. The conductor track on which the secondary coils 116, 118, 120, and 122 are formed is preferably referred to as the secondary coil conductor track 123. In this case, the secondary coils 116, 118, 120, and 122 are arranged on the same conductor support level. Through holes 124, shown as dots, are located before and after each intersection. A four-part target 125 is shown above the secondary coil assembly 115.

[0036] The secondary coil assembly 15 of the inductive encoder system 10 according to the present invention comprises a plurality of secondary coils 16, 18, 20, 22, each having a secondary coil conductor track 23 arranged on a conductor support without crossings. Exemplary embodiments of such an encoder system are shown in Figures 3, 5, and 6. The arrangement of the secondary coil conductor tracks 23 without crossings makes it possible to provide a secondary coil assembly 15 in which the secondary coil conductor tracks 23 do not have through holes 24. For example, connecting conductor tracks 28 (see Figures 3 and 4) to which the secondary coil conductor tracks 23 contact for coupling to a circuit are preferably not considered part of the secondary coil conductor tracks 23.

[0037] Particularly preferably, each secondary coil 16, 18, 20, 22 has a secondary coil surface 32 including a secondary coil contour 34, which corresponds to a contour having a surface between a sine function and a cosine function in the interval of 45° to 225°. This allows for a secondary coil contour 34 having a sine-cosine differential shape to be realized. In addition to the secondary coil assembly 15 shown in Figure 2, the exemplary embodiments shown in Figures 3, 4, and 5 have a secondary coil contour 34 with a sine-cosine differential shape.

[0038] 2, the secondary coil assembly 15 preferably has an assembly contour 30 that corresponds at least in part to a contour having a surface formed by adjacently disposed sine and cosine differential planes, where the assembly contour 30 preferably represents the contour of the surface covered by the entire secondary coil assembly 15.

[0039] In the exemplary embodiment shown in Figure 3, the secondary coil assembly 15 is arranged linearly. A linear arrangement allows for the realization of length measurement systems in particular. In the exemplary embodiment shown in Figures 4 and 5, the secondary coil assembly 15 is arranged in a circular shape. In this case, a circle is preferably superimposed on the secondary coil contour 15 or assembly contour 30. This results in a typical flower-shaped assembly contour 30, as shown in Figures 4 and 5. The circular assembly of the secondary coil assembly 15 is preferably used for rotary encoders, i.e., angle measurement systems in particular.

[0040] Preferably, the secondary coils 16, 18, 20, 22 are arranged adjacent to one another in a longitudinal direction 36 of the secondary coil assembly 15. The adjacent arrangement is preferably realized such that two adjacent secondary coils 16, 18, 20, 22 are electrically insulated from one another. As shown in particular in Figures 4 and 5, an insulating gap 38 may be arranged between two adjacent secondary coils 16, 18, 20, 22. The longitudinal direction 36 is preferably defined by the direction in which the target 25, the position of which is to be determined, is intended to move relative to the secondary coil assembly 15. In particular, in the case of a circular secondary coil assembly 15, the longitudinal direction 36 may be formed in an arcuate shape according to the direction of a corresponding arc.

[0041] When the secondary coils 16, 18, 20, and 22 are formed in a sine-cosine differential shape, the secondary coils 16, 18, 20, and 22 are preferably positioned adjacent to one another so that there is a 90° phase shift between the individual secondary coils 16, 18, 20, and 22. If the first secondary coil 16 is designated as a positive sine coil according to the upper boundary contour line 40, the second secondary coil 18 adjacent to its right can be designated as a positive cosine coil. Correspondingly, this can be followed by a negative sine coil as the third secondary coil 20 and a negative cosine coil as the fourth secondary coil 22. Thus, the four secondary coils 16, 18, 20, and 22 can form a secondary coil set 39. Multiple secondary coil sets can be arranged one behind the other in the secondary coil assembly 15 (see FIGS. 4 and 5). The fourth secondary coil 22, formed as a negative cosine coil, is then followed by the first secondary coil 16 of a further secondary coil set 39, preferably formed as a positive sine coil.

[0042] As shown in FIGS. 3 and 4, the inductive encoder system 10 includes a primary coil 12 having a modulation region 14, a receiver coil 42 having receiver wire sets 44a and 44b and the aforementioned secondary coil assembly 15, which is located within the modulation region. The region surrounded by the primary coil 12 is preferably referred to as the modulation region 14. A primary coil current, preferably an alternating current, flows through the primary coil 12. This current can induce voltages in the secondary coils 16, 18, 20, and 22, particularly those located within the modulation region 14. By positioning a conductive target 25 above at least one of the secondary coils 16, 18, 20, and 22, the induction of voltages in the at least one secondary coil 16, 18, 20, and 22 can be influenced. In FIG. 3, for example, the target 25 is located completely above the second secondary coil 18 and partially above the first secondary coil 16 and the third secondary coil 20.

[0043] The secondary coils 16, 18, 20, 22 of the secondary coil set 39 can be contacted differently with the receiving wire sets 44a, 44b, whereby it is particularly preferred that two secondary coils 16, 18, 20, 22 contacting the same receiving wire set 44a, 44b have different polarities. The different contacts allow the position of the target 25 in the area of ​​the secondary coil set 39 to be determined absolutely.

[0044] In the exemplary embodiment shown in Figures 3 and 4, the receive coil 42 preferably has a first receive wire set 44a and a second receive wire set 44b, each of the secondary coil sets having a first secondary coil 16, a second secondary coil 18, a third secondary coil 20, and a fourth secondary coil 22, with the first secondary coil 16 and the third secondary coil 20, respectively, being contacted by the first receive wire set 44a, and the second secondary coil 18 and the fourth secondary coil 22, respectively, being contacted by the second receive wire set 44b.

[0045] The contact is preferably made by means of the connecting conductor tracks 28. The first secondary coil 16 and the third secondary coil 20 can form a first receiver circuit together with the connecting conductor tracks 28 and the first set of receiver lines 44a arranged thereon. Correspondingly, the second secondary coil 18 and the fourth secondary coil 22 can form a second receiver circuit together with the connecting conductor tracks 28 and the first set of receiver lines 44a arranged thereon. The first secondary coil 16 and the third secondary coil 20 respectively have different polarities, and the second secondary coil 18 and the fourth secondary coil 22 respectively have different polarities. The first to fourth secondary coils 16, 18, 20, 22 are preferably arranged adjacent to one another in ascending order.

[0046] In particular, when no target 25 is located above the secondary coil assembly 15, the voltage induced in the first secondary coil 16 and the voltage induced in the third secondary coil 20 can be at least approximately the same in magnitude (see, in particular, FIG. 3 ). The same preferably applies to the voltages induced in the second secondary coil 18 and the fourth secondary coil 22. Due to the different polarities of the secondary coils 16, 18, 20, 22 located in the same receive line set 44 a, 44 b, at least little current preferably flows in the respective receive circuit unless a target 25 is present above the secondary coil assembly 15. When a target 25 is located at least partially above one of the secondary coils 16, 18, 20, 22, the voltage induced in this secondary coil can be different compared to the additional secondary coils 16, 18, 20, 22 located in the same receive line set 44 a, 44 b, thereby allowing current to flow in the corresponding receive circuit. Preferably, the target 25 is shaped so that it can completely cover at most one of the secondary coils 16, 18, 20, 22.

[0047] As shown in Figures 3 and 4, the through-holes 24 of the secondary coil assembly 15 or the receiver wire sets 44a, 44b are preferably not arranged within the modulation area 14. Particularly preferably, the primary coil 12 is arranged at a first conductor support level and the secondary coil assembly 15 is arranged at a second conductor support level. This eliminates the need for through-holes 24 when the primary coil 12 and the connecting conductor tracks 28 cross, as shown in Figures 3 and 4. The receiver wire sets 44a, 44b can also be arranged at the second conductor support level. In particular, if the receiver wire sets 44a, 44b are arranged outside the modulation area 14, the secondary coils 16, 18, 20, 22 can be contacted to the receiver wire sets 44a, 44b without the need for through-holes 24.

[0048] The primary coil 12 of the encoder system 10 may be formed in a toroidal shape, as shown in Figure 4, thereby forming the modulation region 14 in a circular shape. In the exemplary embodiment shown in Figure 5, the modulation region 14 is formed in a toroidal shape having an outer diameter 46 and an inner diameter 48, with the outer diameter 46 defined by the first primary coil 12a and the inner diameter 48 defined by the second primary coil 12b. Preferably, the direction of current flow 50 in the first primary coil 12a is opposite to the direction of current flow 50 in the second primary coil 12b.

[0049] 4, which preferably has four secondary coil sets 39, the exemplary embodiment shown in FIG. 5 can have 32 secondary coil sets 39. Accordingly, the encoder system shown in FIG. 5 can have a target 25 consisting of 32 sections. The large number of secondary coil sets 39 can significantly increase the resolution of the encoder system 10. In particular, such a high density of secondary coil sets 39 is possible because no through-holes 24 are located within the modulation region 14.

[0050] For clarity, a first portion of the exemplary embodiment shown in FIG. 6 is shown in FIG. 6a. A second portion is shown in FIG. 6b. As shown in FIGS. 6a and 6b, the encoder system 10 may have a third receive line set 44c and a fourth receive line set 44d in addition to a first receive line set 44a and a second receive line set 44b. Furthermore, at least one secondary coil set 39 may include a fifth secondary coil 16a, a sixth secondary coil 18a, a seventh secondary coil 20a, and an eighth secondary coil 22a. Preferably, the fifth secondary coil 16a and the seventh secondary coil 20a are in contact with the third receive line set 44c, and the sixth secondary coil 18a and the eighth secondary coil 22a are in contact with the fourth receive line set 44d. In this case, the first through eighth secondary coils 16a through 22a preferably each have a secondary coil contour 34 formed in a sine-cosine differential shape. In Figures 6-6b, this contour is shown as an oval for easier illustration.

[0051] Preferably, secondary coils contacted by the same receive wire set are arranged in different blocks and offset in the longitudinal direction 36. Thus, the first secondary coil 16 can be arranged in the first block 52, and the third secondary coil 20 can be arranged in the second block 54, with both the first secondary coil 16 and the third secondary coil 20 contacting the first receive wire set 44a and offset in the longitudinal direction 36. Correspondingly, the second secondary coil 18 can be arranged in the first block 52, and the fourth secondary coil 22 can be arranged in the second block 54, with both the first secondary coil 18 and the third secondary coil 20 contacting the second receive wire set 44b and offset in the longitudinal direction 36. Correspondingly, the fifth secondary coil 16a can be disposed in the first block 52, and the seventh secondary coil 20a can be disposed in the second block 54, with both the fifth secondary coil 16a and the seventh secondary coil 20a contacting the third receive wire set 44c and offset in the longitudinal direction 36. Correspondingly, the sixth secondary coil 18a can be disposed in the first block 52, and the eighth secondary coil 22a can be disposed in the second block 54, with both the sixth secondary coil 18a and the eighth secondary coil 22a contacting the fourth receive wire set 44d and offset in the longitudinal direction 36.

[0052] In this case, Figure 6a shows secondary coils 16, 18, 20, 22 in contact with a first set of receiver wires 44a and a second set of receiver wires 44b. Figure 6b shows secondary coils 16a, 18a, 20a, 22a in contact with a third set of receiver wires 44c and a fourth set of receiver wires 44d. In Figures 6-6b, secondary coil conductor tracks 23 arranged at the first wire support level are shown with solid lines. Secondary coil conductor tracks arranged at the second wire support level are shown with dashed lines.

[0053] In Figure 6, two parts of the encoder system 10 shown in Figures 6a and 6b are shown combined. It can be seen in particular from this illustration that adjacent secondary coils 16, 16a, 18, 18a and 20, 20a, 22, 22a can be arranged at different conductor support levels, with preferably no offset between adjacent secondary coils. In particular, adjacent sections of the secondary coil conductor tracks 23 can overlap one another. For reasons of illustration and for better recognition, these sections are shown partially juxtaposed in Figure 6.

[0054] The arrows partially positioned in the secondary coils in Figures 6-6a illustratively indicate the direction of current flow 56 induced in each coil when no target 25 is positioned above. When no target 25 is present, the resulting currents in the receiver wire sets 44a-44d are at least nearly canceled. When a target 25 is positioned at least partially above one of the secondary coils 16-22a, a voltage can be measured in each receiver wire set 44a-44d.

[0055] When the encoder system 10 has multiple consecutive secondary coil assemblies 15, the target 25 is preferably formed to have multiple target elements, as shown in Figure 6. The target elements are preferably spaced apart from one another so as to cover corresponding secondary coils 16, 16a, 18, 18a, 20, 20a, 22, 22a of two consecutive secondary coil assemblies 15. Thus, the target 25 can be formed as a grid, which allows the targets to be positioned simultaneously above corresponding secondary coils 16, 16a, 18, 18a, 20, 20a, 22, 22a.

[0056] The present invention may be configured such that the first and third receiver wire sets 44a and 44c are in conductive contact with each other, and the second and fourth receiver wire sets 44b and 44d are in conductive contact with each other, such that when using the encoder system 10, it may be sufficient to connect two of the receiver wire sets 44a, 44b, 44c, and 44d to an evaluation unit. Preferably, the first and third receiver wire sets 44a and 44c, and the second and fourth receiver wire sets 44b and 44d, are in contact with each other such that adjacent secondary coils 16, 16a, 18, 18a and 20, 20a, 22, 22a have different flow directions 56. [Explanation of symbols]

[0057] 10 Encoder System 12 Primary coil 12a First primary coil 12b Second primary coil 14 Modulation Region 15 Secondary coil assembly 16 First secondary coil 16a 5th secondary coil 18 Secondary Coil 18a 6th secondary coil 20 Third secondary coil 20a 7th secondary coil 22 Fourth secondary coil 22a No. 8 secondary coil 23 Secondary coil conductor track 24 through holes 25 Target 28 connecting conductor tracks 30 Assembly Contours 32 Secondary coil surface 34 Secondary coil outline 36 Longitudinal 38 Insulation gap 39 Secondary Coil Set 40 Upper boundary contour line 42 receiving coil 44a First receive line set 44b Second set of receiving lines 44c Third set of receiving lines 44d Fourth receiving line set 46 outer diameter 48 Inner diameter 50 Current direction 52 First Block 54 Second Block 56 Flow direction 110 Encoder System 112 Primary coil 114 Modulation Region 115 Secondary coil assembly 116 First secondary coil 118 Secondary Coil 120 Third secondary coil 122 Fourth secondary coil 123 Secondary coil conductor track 124 through hole 125 targets

Claims

1. A secondary coil assembly (15) for an inductive encoder system (10) having a plurality of secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a), each secondary coil (16, 16a, 18, 18a, 20, 20a, 22, 22a) having a secondary coil conductor track (23), A secondary coil assembly, characterized in that the secondary coil conductor tracks (23) are arranged on the conductor support without crossing each other in a top view in the direction of the secondary coil axis.

2. 2. The secondary coil assembly of claim 1, wherein each secondary coil (16, 16a, 18, 18a, 20, 20a, 22, 22a) has a secondary coil surface (32) including a secondary coil contour (34), said secondary coil contour (34) corresponding to a contour having a sine-cosine difference region between a sine function and a cosine function included in the interval between 45° and 225°.

3. 2. The secondary coil assembly of claim 1, wherein the secondary coil assembly has an assembly contour that corresponds at least in part to a contour having a surface formed by a plurality of sine-cosine difference regions arranged adjacent to one another.

4. 2. The secondary coil assembly according to claim 1, wherein the secondary coil assembly (15) is arranged in a linear, circular or annular configuration.

5. 2. The secondary coil assembly of claim 1, wherein the secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) are arranged adjacent to one another in a longitudinal direction (36) of the secondary coil assembly (15).

6. 6. The secondary coil assembly according to claim 5, wherein the secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) are arranged in a plurality of blocks (52, 54) arranged parallel to each other in the longitudinal direction (36).

7. 6. The secondary coil assembly of claim 5, wherein the wire support has at least one wire support level, and wherein the adjacent secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) are located on the same wire support level, or the adjacent secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) are located on different wire support levels.

8. 8. An inductive encoder system (10) comprising at least one primary coil (12, 12a, 12b) having a modulation region (14), and at least one receiver coil (42) having at least one receiver wire set (44a, 44b, 44c, 44d) and a secondary coil assembly (15) according to any one of claims 1 to 7, wherein the secondary coil assembly (15) is disposed within the modulation region (14).

9. 9. The inductive encoder system of claim 8, wherein the inductive encoder system has at least one secondary coil set (39) consisting of a plurality of secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a), the secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) of the at least one secondary coil set (39) being contacted by the at least one receiver wire set (44a, 44b, 44c, 44d) such that the secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) contacted by the same receiver wire set have different flow directions (56).

10. 10. The inductive encoder system of claim 9, wherein the at least one receiver coil has a first set of receiver wires and a second set of receiver wires; and the at least one secondary coil set has a first secondary coil, a second secondary coil, a third secondary coil, and a fourth secondary coil, the first secondary coil and the third secondary coil being in contact with the first set of receiver wires and the second secondary coil and the fourth secondary coil being in contact with the second set of receiver wires.

11. 11. The inductive encoder system of claim 10, wherein the at least one receiver coil comprises a third receiver wire set (44c) and a fourth receiver wire set (44d); and the at least one secondary coil set (39) comprises a fifth secondary coil (16a), a sixth secondary coil (18a), a seventh secondary coil (20a), and an eighth secondary coil (22a), the fifth secondary coil (16a) and the seventh secondary coil (20a) being in contact with the third receiver wire set (44c), and the sixth secondary coil (18a) and the eighth secondary coil (22a) being in contact with the fourth receiver wire set (44d).

12. 10. The inductive encoder system according to claim 8, comprising the secondary coil assembly according to claim 6, wherein the secondary coils (16, 16a, 18, 18a, 20, 20a, 22, 22a) contacted with the same set of receiving wires (44a, 44b, 44c, 44d) are arranged in different blocks (52, 54) offset in the longitudinal direction (36) of the secondary coil assembly (15).

13. 10. The inductive encoder system of claim 9, wherein the inductive encoder system (10) comprises a first receive coil (42) and a second receive coil (42), the first receive coil (42) having multiple secondary coil sets (39) and the second receive coil (42) having exactly one secondary coil set (39).

14. 9. The inductive encoder system of claim 8, wherein the at least one primary coil (12, 12a, 12b) is disposed at a first wire support level and the secondary coil assembly (15) is disposed at a second wire support level.

15. 9. The inductive encoder system according to claim 8, wherein the at least one primary coil (12, 12a, 12b) is formed in a circular ring shape.

16. 16. The inductive encoder system of claim 15, wherein the modulation region (14) is formed in a toroidal shape having an outer diameter (46) and an inner diameter (48), the outer diameter (46) being defined by a first primary coil (12a) and the inner diameter (48) being defined by a second primary coil (12b).

17. 17. The inductive encoder system of claim 16, wherein the direction of current flow in the first primary coil is opposite to the direction of current flow in the second primary coil.

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