Encoder systems for drives

Abstract

To achieve encoder system that is constructed in a space-saving manner, has a low inertia moment and high accuracy, and permits simple assembly.SOLUTION: An encoder system 1 for a drive is provided, comprising: a revolution counter having a Wiegand sensor 23 which is disposed on a stationary portion 13 of the encoder system 1, and at least two pairs of magnets which in a revolving direction 5 are disposed at different positions on a rotation portion 15 of the encoder system 1, wherein the pairs of magnets each comprises a revolution counter comprising a first magnet 35 and second magnet 37; and a position encoder having a magnetic field sensor 43 which is disposed in the stationary portion 13, and a magnetic strip 47 which is disposed in the rotation portion 15, wherein, in each pair of magnets, the first magnet 35, the magnetic strip 47 of the position encoder and the second magnet 37 in terms of a first direction are disposed in this sequence in the rotation portion 15.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an encoder system for a drive and an electric motor. [Background technology]

[0002] In the prior art, encoder systems are known that include a magnetic rotation counter (multi-turn encoder) and a magnetic position encoder (single-turn encoder). The rotation counter is typically specified to count the number of rotations of a motor shaft. The position encoder typically determines the angular position of the shaft. The magnetic circuits and magnetic sensors of the rotation counter and the position encoder are often spatially isolated from each other to avoid distortion of the magnetic field of the other encoder.

[0003] However, encoder systems known in the prior art require a large installation space, have a large diameter or a high moment of inertia, are low in accuracy, or are only located at the end of the shaft. Summary of the Invention [Problem to be solved by the invention]

[0004] It is an object of the present disclosure to provide an encoder system for a drive and an electric motor that is improved over the prior art, in particular an encoder system that is configured or installed in a particular space-saving manner, has a low moment of inertia, high accuracy, or allows for simple manufacture or assembly. [Means for solving the problem]

[0005] This object is achieved by an encoder system for a drive according to claim 1 and by an encoder system and an electric motor according to the corresponding claims.

[0006] According to one aspect, an encoder system for a drive device is defined, the encoder system comprising a Wiegand sensor arranged in a fixed portion of the encoder system and at least two magnet pairs arranged at different positions in the rotational direction on a rotating portion of the encoder system, each magnet pair comprising a first magnet and a second magnet; a magnetic field sensor arranged in the fixed portion and a position encoder having a magnetic strip arranged in the rotating portion, the first magnet, the magnetic strip of the position encoder, and the second magnet being arranged in that order on the rotating portion for each magnet pair.

[0007] According to a further aspect, an electric motor having a shaft and an encoder system according to an embodiment is provided.

[0008] A further aspect relates to an encoder system for a drive comprising: a revolution counter having a first sensor disposed on a first sensor board of the encoder system; a position encoder having a second sensor disposed on a second sensor board of the encoder system; and a motherboard designed for connection to a drive enclosure, wherein the first sensor board and the second sensor board are directly connected to the motherboard.

[0009] A typical embodiment of the encoder system is defined as a drive, in particular an electric machine, for example an electric motor or a gearbox.

[0010] In a typical embodiment, the encoder system comprises a revolution counter and a position encoder. In a typical embodiment, the revolution counter and the position encoder are each based on a magnetic measurement principle. The revolution counter is specifically embodied as a magnetic revolution counter. The revolution counter is typically defined to count the number of revolutions of a shaft of a drive device. Here, "revolution" should be understood to mean, for example, a full revolution, a half revolution, a quarter revolution, or an eighth revolution. The revolution counter may also be defined to count the number of revolutions in a specific direction of rotation.

[0011] A rotation counter typically includes a Wiegand sensor. A Wiegand sensor, also known as a pulse wire sensor, typically includes a Wiegand wire and a Wiegand coil. The Wiegand coil can be disposed around the Wiegand wire, for example. The Wiegand wire typically has parallel soft and hard magnetic regions. Wiegand wires typically have a hysteresis curve with two distinct reversal points. Specifically, when the magnetic field in or around a Wiegand wire changes, a type of macroscopic Barkhausen effect, commonly known as the Wiegand effect, occurs. A sudden change in the magnetization of the Wiegand wire can induce a voltage pulse in the Wiegand coil, the size and shape of which are not a function of how rapidly the external magnetic field changes. Wiegand sensors are typically specified to count the number of shaft revolutions under voltage or in the absence of voltage. As the drive shaft rotates, a magnet or magnet pair connected to the shaft in a rotatably fixed manner can generate a variable magnetic field on the Wiegand sensor fixed in a fixed manner. For example, the generated voltage pulses indicate at least a partial rotation of the shaft, particularly a half rotation, a quarter rotation, or an eighth rotation. In an embodiment, the voltage pulses can be used to store the rotations in a non-volatile memory.

[0012] In a typical embodiment, the Wiegand sensor is disposed in a fixed portion of the encoder system. The fixed portion of the encoder system is typically defined to be rotatably connected to the housing of the drive device or is rotatably connected to the housing. The fixed portion specifically does not rotate in conjunction with the shaft of the drive device. For example, the Wiegand sensor can be disposed on or above a first sensor board of the encoder system.

[0013] The rotation counter typically includes at least two magnet pairs. The magnet pairs are typically arranged on a rotating part of the encoder system. The rotating part of the encoder system is typically provided for connection to the shaft of the drive device in a rotatably fixed manner or is connected to the shaft in a rotatably fixed manner. The rotating part of the encoder system is typically rotatable about an axis of rotation of the encoder system. The axis of rotation may in particular at least substantially correspond to the axis of the shaft of the drive device.

[0014] In a typical embodiment, at least two magnet pairs are arranged at different positions within the rotation direction. For example, two magnet pairs can be arranged opposite each other. A rotation counter typically includes two, four, or eight magnet pairs. Specifically, the magnet pairs can be arranged uniformly within the rotation direction or at equidistant positions within the rotation direction.

[0015] In typical embodiments, the magnet pairs each include a first magnet and a second magnet. The first magnet of the magnet pair and the second magnet of the magnet pair are typically positioned at least substantially in the same position within the rotational direction. The first magnetic dipole moment of the first magnet is typically aligned at least substantially antiparallel to the second magnetic dipole moment of the second magnet. In further embodiments, the dipole moments of the first magnet and the second magnet can be aligned at other angular positions to generate a magnetic circuit with the first magnetic flux lines.

[0016] The first and second magnetic dipole moments are typically aligned to be at least substantially perpendicular to the connection axis between the first and second magnets, where at least substantially perpendicular, at least substantially parallel, and at least substantially anti-parallel should be understood in particular to be exactly perpendicular, parallel, or anti-parallel alignment, or within a displacement of at most 15°, in particular at most 10°, or at most 5° from exactly perpendicular, parallel, or anti-parallel alignment.

[0017] The first and second magnets in the rotational direction are typically arranged with alternating polarities. As the shaft rotates, the magnet pair generates opposing magnetic fields at the Wiegand sensor location, specifically in an alternating fashion. The first and second magnets are typically permanent magnets, specifically permanent magnets with high energy density and residual magnetic flux density, such as neodymium, particularly neodymium-iron-boron magnets. The first and second magnets are typically embodied as block magnets.

[0018] A typical encoder system includes a position encoder, in particular a magnetic position encoder. The position encoder is typically specified to determine the absolute position of a shaft, for example the angular alignment of the shaft. The position encoder typically comprises a magnetic field sensor. The magnetic field sensor is typically arranged on a fixed part of the encoder system, for example on a second sensor board of the encoder system. In a typical embodiment, the magnetic field sensor is embodied as a Hall sensor, or as a Hall sensor array having, for example, four Hall sensors or eight Hall sensors, or any other number of Hall sensors, or as a sensor coil, or as an MR (Magnetoresistive) sensor, or as a GMR (Giant Magnetoresistive) sensor array.

[0019] In a typical embodiment, the position encoder includes a magnetic strip. The magnetic strip is typically embodied so as to surround a shaft or a rotating part of the encoder system. The gap between the magnetic strip and the magnetic field sensor is typically at most 1 mm, in particular at most 0.7 mm, or at most 0.5 mm, or at least 0.1 mm, in particular at least 0.2 mm. A small gap between the magnetic strip and the magnetic field sensor can enable particularly accurate determination of the magnetic field of the magnetic strip by the magnetic field sensor.

[0020] In a typical embodiment, the magnetic strip includes at least two magnetic tracks, for example, exactly two or exactly three magnetic tracks. The magnetic tracks in the rotation direction typically have magnetic portions with alternating polarity in each case. The magnetic tracks are typically magnetized to have weak magnetization. For example, the magnetic portions of the magnetic tracks can be made of ferrite, especially hard ferrite, or ferrite.

[0021] The magnetic strip in the rotational direction typically has a code, particularly a magnetic code. The code is typically suitable for determining the absolute position of the magnetic embodiment of the scale, particularly the shaft. The magnetic strip, particularly the at least two magnetic tracks, can have, for example, a Nonius code (Vernier code) or a Gray code. For example, the magnetic strip can have two magnetic tracks divided according to the Nonius principle. For example, the magnetic strip can have two magnetic tracks with a difference of one in the number of pole pairs. For example, the first magnetic track can have 63 pole pairs, and the second magnetic track can have 64 pole pairs. The absolute or angular position of the shaft is typically determined by an algorithm, such as a Nonius algorithm, based on the ambiguous phase relationship of the magnetic fields measured on each magnetic track. In other embodiments, the magnetic strip can have three or more tracks.

[0022] In a typical embodiment, in each magnet pair, the first magnet, the magnetic strip of the position encoder, and the second magnet are arranged in this order on the rotating part in a first direction. Specifically, in the first direction, the magnetic strip is arranged between the first magnet of the magnet pair and the second magnet of the magnet pair. For example, the first direction for each magnetic pair can be oriented along an axis connecting the first magnet and the second magnet. The first direction is typically oriented in an axial or radial direction. The arrangement of the magnetic strip between the first magnet and the second magnet can particularly provide the advantage that the encoder system can be made in a particularly compact manner.

[0023] In a typical embodiment, the encoder system includes at least one first discharge element, made of a magnetically conductive material, disposed between the first magnet and the magnetic strip or between the second magnet and the magnetic strip. Specifically, in the first direction, at least one first discharge element in each magnet pair is disposed between the first magnet and the magnetic strip or between the second magnet and the magnetic strip. Specifically, two first discharge elements in each magnet pair are disposed between the first magnet and the magnetic strip and between the second magnet and the magnetic strip.

[0024] The at least one first discharge element is typically arranged on the rotating part. For example, the first discharge elements in the rotational direction may be arranged at the positions of the magnet pairs, respectively. Specifically, the first discharge elements can be embodied in the same way in both cases or can be arranged in the same way with respect to the magnet pairs in both cases. In a further exemplary embodiment, the at least one first discharge element is arranged to surround the rotating part of the encoder system. The at least one first discharge element can typically be configured to be at least substantially ring-shaped or as a disk. Specifically, the at least one first discharge element can be arranged to be coaxial with the rotation axis of the encoder system.

[0025] The at least one first discharge element typically includes or is made of a magnetically conductive material. The magnetically conductive material here should be understood to be, in particular, a ferromagnetic or ferrimagnetic material. The at least one first discharge element in each magnet pair is typically configured to emit a stray magnetic field of the first magnet or the second magnet. For example, the at least one first discharge element is configured to emit a stray magnetic field in a second direction, and the second direction is aligned to be at least substantially perpendicular to the first direction. Specifically, the at least one first discharge element is configured to emit a stray magnetic field such that the stray magnetic field is reduced at the location of the magnetic strip or the location of the magnetic field sensor.

[0026] In a typical embodiment, the encoder system is made of a magnetically conductive material and includes a second discharge element disposed on the fixed portion. A magnetic field sensor of the position encoder is typically disposed between the magnetic strip and the second discharge element in a second direction aligned at least substantially perpendicular to the first direction. The second direction specifically exists within a cross section extending along the axis of rotation through the magnetic field sensor. The second discharge element is typically embodied as a block or plate. In an embodiment, the second discharge element includes or is composed of a ferrite, such as a soft magnetic ferrite. The second discharge element can be disposed on a second sensor board. In an embodiment, the second discharge element is connected to the second sensor board. For example, the second discharge element can be adhesively or soldered to the second sensor board.

[0027] In a typical embodiment, the second discharge element extends in the first direction over at least a region of the magnetic strip, specifically over a region between at least two first discharge elements. When the first direction is aligned axially, the "region" in this description should be understood specifically as an axial region; when the first direction is aligned radially, it should be understood specifically as a radial region. The second discharge element is typically defined around the magnetic field sensor of the position encoder, specifically such that the stray magnetic field is oriented substantially parallel to at least the first direction.

[0028] The rotating part typically includes a carrier made of a magnetically conductive material, with the magnetic strip and at least two magnet pairs disposed on the carrier. The carrier is typically defined so that a stray magnetic field is oriented around the magnetic field sensor or magnetic strip, specifically at least substantially parallel to the first direction. In an embodiment, the magnetic strip carrier is disposed between the magnetic strip and the carrier. The magnetic strip carrier can be made of a magnetically conductive material.

[0029] In a typical embodiment, the magnetic field sensor of the position encoder is shielded from interfering magnetic fields by a shielding system of the encoder system. The shielding system typically includes at least one of a group including at least one first discharge element, a second discharge element, and a carrier. For example, the shielding system may include at least one first discharge element between the first magnet of the magnet pair and the magnetic strip, a second discharge element between the second magnet of the magnet pair and the magnetic strip, and a carrier. For example, the shielding system may be configured to interlace the weak magnetic circuit of the position encoder and the ferromagnetic circuit of the revolution counter. Interfering magnetic fields related to the magnetic field sensor of the position encoder can be specifically radiated. Interfering magnetic fields may include, for example, stray magnetic fields of the magnet pair or external interfering magnetic fields. External interfering magnetic fields may emanate, for example, from the operation of a drive device, specifically an electric motor, or from external electromagnetic radiation. Shielding the magnetic field sensor according to this embodiment can have the advantage of being able to determine the absolute position of the shaft with high precision. In particular, high precision can be achieved while the structural volume of the encoder system is small.

[0030] The ratio of the first remanent magnetic induction of the magnetic strip to the second remanent magnetic induction of the first magnet of the magnet pair or the second magnet of the magnet pair is typically at least 1:15, particularly at least 1:10, or at least 1:8, or at most 1:2, particularly at most 1:3, or at most 1:4. This ratio may specifically be between 1:10 and 1:3. For example, the first remanent magnetic induction of the magnetic strip may be between 0.1 T and 0.4 T. The second remanent magnetic induction of the first magnet or the second magnet may be between 0.8 T and 1.5 T.

[0031] In a typical embodiment, the Wiegand sensor and the magnetic field sensor in the direction of rotation are positioned to be offset from each other about the axis of rotation of the rotating part. The Wiegand sensor and the magnetic field sensor are typically positioned to be offset from each other by at least half the angular spacing between two adjacent magnet pairs in the direction of rotation. For example, in an embodiment with eight magnet pairs, the Wiegand sensor and the magnetic field sensor are positioned to be offset from each other by at least 22.5°, and in the case of four magnet pairs, this offset is at least 45°. Severe distortion of the magnetic field of the magnet pair at the location of the Wiegand sensor by a second discharge element on the magnetic field sensor can be avoided, for example, by a minimal offset in the direction of rotation.

[0032] In a typical embodiment, the first direction is aligned to be the axial direction. In each magnet pair, the first magnet, the magnetic strip, and the second magnet are specifically arranged in this order on the rotating part in the axial direction. In each magnet pair, the first magnet and the second magnet are typically arranged to be in a plane that includes the axis of rotation. In the axial direction, the first magnet and the second magnet are typically arranged to be offset from each other. The axial configuration can have the advantage, for example, that the encoder system can be installed with a particularly short diameter, or that the encoder system will not be destroyed if axial displacement of the shaft occurs.

[0033] In a typical embodiment, at least one first discharge element in each magnet pair is arranged axially between the first magnet and the magnetic strip or between the second magnet and the magnetic strip. In a typical embodiment, the second discharge element is arranged radially outward of the magnetic field sensor. In a typical embodiment, the second discharge element is arranged radially outward of the magnetic field sensor, specifically the fixed portion. For example, the order from radially inner to radially outer is magnetic strip, magnetic field sensor, second discharge element. The terms "radial," "tangential," and "axial" used herein typically refer to the axis of rotation.

[0034] In a typical embodiment, the carrier is embodied as a sleeve, and the sleeve is provided to be connected to the shaft of the drive device in a rotatably fixed manner. In the radial direction, the sleeve is typically arranged so as to be at least partially inside the magnet pairs or inside the magnetic strip. In the radial direction, the sleeve is typically arranged so as to be at least partially inside the magnet pairs and inside the magnetic strip.

[0035] In typical embodiments, the sleeve is embodied as one member. In other embodiments, the sleeve is embodied as two members. Specifically, at least one or all of the elements of the group including the first discharge element, the magnets of the magnet pair, and the track of the magnetic strip may be respectively disposed in both members of the sleeve.

[0036] In a further exemplary embodiment of the encoder system, the first direction is aligned to be the radial direction. In each magnet pair, the first magnet and the second magnet are arranged to be offset from each other in the radial direction. In the radial direction, the magnetic strip in each magnet pair is specifically arranged between the first magnet and the second magnet. The radial embodiment may specifically allow for a particularly flat configuration in the axial direction.

[0037] In a typical embodiment, at least one first discharge element in each magnet pair is disposed radially between the first magnet and the magnetic strip or between the second magnet and the magnetic strip, and in a typical embodiment, the second discharge element, the magnetic field sensor, and the magnetic strip are disposed axially in this order.

[0038] In a typical embodiment, the carrier is embodied as a disk, which is provided to be rotatably connected to a shaft, the disk typically being arranged coaxially with the axis of rotation of the encoder system.

[0039] A typical embodiment includes an electric motor having a shaft and an encoder system according to the present invention. The fixed part of the encoder system is typically connected in a rotatably fixed manner to the housing of the electric motor. The rotating part of the encoder system is typically connected in a rotatably fixed manner to the shaft of the electric motor. The shaft of the electric motor may be provided with a further permanent magnet, for example a further permanent magnet of the rotor of the electric motor.

[0040] In a typical embodiment, the shaft of the electric motor is embodied as a hollow shaft, in particular as a continuous hollow shaft. A hollow shaft can offer the advantage that, for example, cables can be routed through the hollow shaft to save space. In a further typical embodiment, the shaft is embodied as a solid shaft.

[0041] An exemplary embodiment that can be specifically combined with the exemplary encoder system described herein relates to an encoder system having a revolution counter. The revolution counter includes a first sensor, which is disposed on a first sensor board of the encoder system. The first sensor is typically a magnetic sensor, such as a Wiegand sensor. The Wiegand sensor can be embodied, for example, as an SMD component. The encoder system typically includes a position encoder with a second sensor, which is disposed on a second sensor board of the encoder system. The second sensor is typically a magnetic sensor, such as the magnetic field sensor according to the present embodiment. The second sensor board can hold additional electrical auxiliary components, such as resistors, capacitors, or memory chips. The second sensor board can specifically hold a second discharge element according to the present embodiment. The second discharge element is typically connected to the second sensor board, for example, by soldering or adhesive bonding.

[0042] A typical encoder system comprises a motherboard defined to be connected to the housing of the drive device. In an embodiment, the motherboard provides an electrical connection between the first sensor board and the second sensor board by conductor tracks on the motherboard. The motherboard typically comprises various electrical components, for example, electrical protection circuits or voltage regulators. In a typical embodiment, the motherboard provides an electrical interface, for example, a board plug, for supplying power to the encoder system or for communication between the motherboard and an electronic evaluation device of the encoder system.

[0043] The first and second sensor boards are typically directly connected to the motherboard. The first and second sensor boards are not specifically releasable from the motherboard in a non-destructive manner. The first or second sensor board can be connected to the motherboard by, for example, a plug connection, an adhesive connection, or a soldered connection. The electrical connection between the first or second sensor board and the motherboard can be provided by a soldered connection or a cable connection. In a further embodiment, the first and second sensor boards and the motherboard can be embodied as rigid / flexible circuit boards.

[0044] In typical embodiments, the first sensor board or the second sensor board, in particular both, are aligned, in particular at least substantially axially, and in particular at least substantially axially tangentially at a point of each sensor and at least substantially tangentially at the axis of rotation of the encoder system. The motherboard is typically aligned at least substantially perpendicular to the axis of rotation. "At least substantially" should be understood, in particular, to mean a deviation of up to 20°, in particular up to 10°, or up to 5° from exact axial, tangential, or radial alignment. In typical embodiments, the first sensor board or the second sensor board, in particular both, are aligned at least substantially perpendicular to the motherboard.

[0045] Compared to the prior art, exemplary embodiments of the encoder system may in particular offer the advantage that a compact construction is provided. In particular, the embodiments may have a short diameter or a short axial thickness. Furthermore, the embodiments may offer the advantage that the absolute position can be determined with high accuracy. A further advantage of exemplary embodiments may be that the magnetic field sensor is shielded against interfering magnetic fields, in particular against stray magnetic fields of a rotation counter or external interfering magnetic fields. [Brief explanation of the drawings]

[0046] Further advantages and features of preferred embodiments of the present invention are explained below with reference to the accompanying drawings. [Figure 1] 1 shows a schematic cross-sectional view of a typical encoder system. [Figure 2] FIG. 2 is a schematic cross-sectional view of a typical encoder system, specifically showing cross section A in FIG. 1. [Figure 3] FIG. 2 is a schematic cross-sectional view of a typical encoder system, specifically showing cross section B in FIG. 1. [Figure 4] 1 shows a schematic cross-sectional view of a further exemplary encoder system; DETAILED DESCRIPTION OF THE INVENTION

[0047] Although typical embodiments will be described below with reference to the drawings, the present invention is not limited to these exemplary embodiments, and the scope of the present invention is determined by the claims.

[0048] In the description of the drawings, identical or corresponding parts are given the same reference numerals, and features already described in other figures may not be described again for the sake of clarity.

[0049] FIG. 1 is a schematic cross-sectional view of a typical encoder system 1, showing a schematic cross-section along a rotation axis 3 of the encoder system 1. The encoder system 1 comprises a fixed part 13 and a rotating part 15. The fixed part 13 is defined to be connected to a housing of a drive device in a rotatably fixed manner. The rotating part 15 is connected to a shaft 11 of the drive device. The shaft 11 and the rotating part 15 are rotatable about the rotation axis 3. The embodiment shown in FIGS. 1 to 4 is a specific embodiment of an encoder system aligned such that a first direction of the encoder system is axial.

[0050] The encoder system 1 comprises a revolution counter, which will be explained below with particular reference to Figures 1 and 2. Figure 2 specifically shows section A of Figure 1. In Figure 2 the revolution counter is generally designated by the reference numeral 21. The revolution counter comprises a Wiegand sensor 23 arranged on the fixed part 13, in particular on a first sensor board 29. The Wiegand sensor 23 comprises a Wiegand wire 25 and a Wiegand coil 27. The Wiegand coil 27 is wound around the Wiegand wire 25.

[0051] The rotation counter comprises magnet pairs arranged on the rotating part 15. The magnet pairs are arranged in particular on a carrier 55 of the encoder system 1, which in FIG. 1 is embodied in an exemplary manner as a sleeve. The carrier 55 is made of a magnetically conductive material, in particular a ferromagnetic material. In the exemplary embodiment of FIGS. 1 and 2, four magnet pairs are arranged on the rotating part 15. The magnet pairs in particular comprise, in FIGS. 1 and 2, a first magnet pair 32 arranged close to the magnetic field sensor 43, a second magnet pair 33 arranged close to the Wiegand sensor 23, and two further magnet pairs 34, which are arranged between the first magnet pair 32 and the second magnet pair 33 and are in each case arranged opposite each other (FIG. 2). The magnet pairs are arranged uniformly in the direction of rotation 5, with an angular spacing of 90° between adjacent magnet pairs in the direction of rotation 5.

[0052] Each magnet pair includes a first magnet 35 and a second magnet 37. In each magnet pair, the first magnet 35 and the second magnet 37 have antiparallel magnetic dipole moments. The magnet pairs within the rotational direction 5 have alternating polarities. For example, as shown in FIG. 2, the first magnets 35 within the rotational direction 5 have alternating polarities. Specifically, the first magnets 35 are aligned so that alternating north or south poles of the first magnets 35 in the direction of rotation 5 face radially outward. The second magnets 37 in the direction of rotation 5 also have alternating polarities.

[0053] In each magnet pair, the first magnet 35 and the second magnet 37 form a magnetic circuit with a first magnetic flux line 39. The magnetic circuit generated by the magnet pair when rotating the magnet pair toward the position of the Wiegand sensor 23 is suitable for reversing the polarity of the Wiegand wire 25. The reversal of the polarity of the Wiegand wire 25 can induce a voltage pulse in the Wiegand coil 27. The voltage pulse can be used as a count signal for counting rotations, for example, to detect a quarter rotation in FIG. 1. In a voltage-free encoder system state, the voltage pulse can also serve to store a count signal or a count result in the non-volatile memory of the encoder system 1.

[0054] The encoder system 1 comprises a position encoder, as particularly shown in Figures 1 and 3. Figure 3 is a diagram specifically showing section B of Figure 1. In Figure 3, the position encoder is generally designated by the reference numeral 41. The position encoder comprises a magnetic field sensor 43, for example a Hall sensor array. The magnetic field sensor 43 is arranged on the fixed part 13 of the encoder system 1, in particular on a second sensor board 45 of the encoder system 1. The magnetic field sensor 43 is shown to be arranged 180° offset in the direction of rotation 5 relative to the Wiegand sensor 23.

[0055] In a further embodiment, the magnetic field sensors are positioned at less than 180° in the direction of rotation.

[0056] The position encoder includes a magnetic strip 47 disposed on the rotating part 15. The magnetic strip 47 is specifically disposed on a magnetic strip carrier 49. The magnetic strip carrier 49 is rotatably fixed to the carrier 55 and is axially coaxially connected thereto. In FIGS. 1 and 3, the magnetic strip 47 has two magnetic tracks with a Nonius code (Vernier code). The magnetic tracks with alternating polarity portions are specifically shown in the cross-sectional view of FIG. 3. In the exemplary embodiment of FIG. 3, the magnetic tracks have, for example, 63 pairs of poles, although a smaller number is shown for simplicity. The other magnetic tracks, not shown, have, for example, 64 pairs of poles. The magnetic field sensor 43 is defined to measure the magnetic field of the magnetic strip 47, for example, the second magnetic flux lines 57 of the two magnetic tracks of the magnetic strip 47 shown schematically in Figures 1 and 3.

[0057] The position encoder typically includes a magnetic strip with a nonius code, which determines the phase of each magnetic track based on the magnetic field measurement of a magnetic field sensor. The phase indicates, for example, the angular position of the pole of the magnetic strip near or adjacent to the magnetic field sensor. Due to the heterogeneity of the magnetic tracks according to the nonius principle, there is an ambiguous phase relationship between the phases of the magnetic strip, from which the absolute position of the shaft can be calculated based on the phase of the magnetic track. In a further embodiment, the absolute position can be calculated based on the Gray code of the magnetic strip.

[0058] In each magnet pair in FIG. 1, a first magnet 35, a magnetic strip 47, and a second magnet 37 are arranged in this order in a first direction, that is, the axial direction in FIG. The magnetic strip 47 in each magnet pair is positioned axially, specifically between the first magnet 35 and the second magnet 37 .

[0059] The first discharge elements 51 are disposed on the rotating portion 15 between the first magnet 35 and the magnetic strip 47, and between the second magnet 37 and the magnetic strip 47. Specifically, the first discharge elements 51 are disposed on a carrier 55. In FIGS. 1 and 2, the first discharge elements 51 are embodied as annular disks around the carrier 55. The first discharge elements 51 are configured to emit stray magnetic fields, such as stray lines 40, emitted from the magnet pair, specifically in a second direction oriented perpendicular to the first direction. This allows the stray magnetic fields having stray lines 40 to be short-circuited, for example, via the first discharge elements 51 and the carrier 55, and specifically, to be isolated from the magnetic field sensor 43 and the magnetic strip 47.

[0060] The encoder system 1 includes a second discharge element 53. The second discharge element 53 is disposed on the fixed portion 13 of the encoder system 1, and specifically, is fixedly connected to the second sensor board 45, for example, by adhesive bonding. The second discharge element 53 is disposed radially outward of the magnetic field sensor 43. Specifically, the magnetic field sensor 43 is disposed between the second discharge element 53 and the magnetic strip 47 in the second direction, which is the radial direction. The second discharge element 53 in FIG. 1 is embodied as a ferrite block. The second discharge element 53 in FIG. 1 extends beyond the axial region between the two first discharge elements 51 on both axial sides.

[0061] In FIG. 1, the first discharge element 51, the second discharge element 53 and the carrier 55 form a shielding system for shielding or discharging in an interfering magnetic field. The magnetic strip 47 and the magnetic field sensor 43 can be shielded from interfering magnetic fields, specifically the stray magnetic field of the magnet pair, by discharging them. For example, a precise determination of the absolute position can be made possible by the shielding. Specifically, the shielding system guides the magnetic circuit generated by the magnet pair around the magnetic field sensor 43 to the position of the magnetic field sensor 43. The further stray magnetic field of the magnet pair in the direction of the magnetic field sensor 43 is specifically discharged in a second direction by the first discharge element 51. This shielding system makes it possible to handle encoder systems in which the weak magnetic circuit of the position encoder (second magnetic flux line 57) and the ferromagnetic circuit of the revolution counter (first magnetic flux line 39) intersect. In particular, the weak magnetic circuit and the ferromagnetic circuit can be appropriately decoupled from each other to determine the absolute position. For example, a particularly space-saving encoder system can be provided.

[0062] Figure 4 shows a schematic cross-sectional view of an encoder system 61. A rotating portion 65 of the encoder system 61 is shown in Figure 4 in a simplified manner for clarity. The encoder system 61 comprises a fixed part 63 having a motherboard 81 defined for rotatably and fixedly connecting to the housing of the drive device. The motherboard 81 in particular has fastening holes 83 defined for fastening the motherboard 81 to the housing of the drive device, for example by fastening screws.

[0063] The encoder system 61 includes a revolution counter with a first sensor 67, which in FIG. 4 for example comprises a Wiegand sensor in one of the present embodiments. The first sensor 67 is arranged on a first sensor board 69. The first sensor board 69 is mechanically connected to a motherboard 81 via a first plug connection 71. The first plug connection 71 is provided by a cam on the first sensor board 69 that engages in an opening in the motherboard 81. In addition, electrical contacts on the first sensor board 69 and the motherboard 81 are soldered to each other.

[0064] The encoder system 61 of Figure 4 includes a position encoder having a second sensor 77, e.g., a magnetic field sensor in one of the present embodiments. The second sensor 77 is disposed on a second sensor board 79. In the exemplary embodiment of Figure 4, a second discharge element 85 is disposed radially outward of the second sensor 77 on the second sensor board 79. The second sensor board 79 is mechanically connected to the motherboard 81 via a second plug connection 87. The second plug connection 87 is provided by a cam on the second sensor board 79 that engages with an opening in the motherboard 81. The electrical contacts on the second sensor board 79 and the motherboard 81 are soldered together.

[0065] The first sensor board 69 and the second sensor board 79 are each aligned perpendicular to the motherboard 81. Specifically, the first sensor board 69 at a point of the first sensor 67 is aligned so as to be approximately tangential to the rotation axis of the encoder system 61. The second sensor board 79 at a point of the second sensor 77 is aligned so as to be approximately tangential to the rotation axis.

[0066] Encoder systems according to embodiments may, for example, be easily assembled, flexibly adapted to various drive arrangements, or manufactured in a cost-effective manner.

[0067] The features of the exemplary embodiments of Figures 1 to 4 can be combined with each other, and the encoder system having the substrate assembly according to the exemplary embodiment of Figure 4 can specifically use features described in other encoder systems disclosed in this specification.

Claims

1. An encoder system (1) for a drive device, comprising: a Wiegand sensor (23) arranged on the fixed part (13) of the encoder system (1); and The encoder system (1) has at least two magnet pairs arranged at different positions in the direction of rotation (5) on the rotating part (15), a rotation counter, each of said magnet pairs comprising a first magnet (35) and a second magnet (37); a position encoder having a magnetic field sensor (43) arranged on the fixed part (13) and a magnetic strip (47) arranged on the rotating part (15); Equipped with An encoder system (1) in which, for each of the magnet pairs, the first magnet (35), the magnetic strip (47) of the position encoder, and the second magnet (37) are arranged on the rotating part (15) in this order in a first direction.

2. The encoder system (1) according to claim 1, wherein the Wiegand sensor (23) and the magnetic field sensor (43) are arranged offset from each other with respect to the axis of rotation (3) of the rotating part (15).

3. The encoder system (1) according to claim 1 or claim 2, wherein the magnetic strip (47) comprises at least two magnetic tracks.

4. 4. The encoder system (1) according to claim 1, wherein the ratio of the residual magnetic induction of the magnetic strip (47) to the residual magnetic induction of the first magnet (35) of the magnet pair or the second magnet (37) of the magnet pair is at least 1:15 and at most 1:

2.

5. At least one first discharge element (51) made of a magnetically conductive material and arranged between the first magnet (35) and the magnetic strip (47) and / or between the second magnet (37) and the magnetic strip (47), a second discharge element (53) made of a magnetically conductive material and arranged on said fixed part (13); the magnetic field sensor (43), aligned at least substantially perpendicular to the first direction, is disposed between the magnetic strip (47) and the second discharge element (53) in a second direction; the rotating part (15) comprises a carrier (55) made of a magnetically conductive material, the magnetic strip (47) and the at least two magnet pairs being arranged on the carrier (55); 2. The encoder system (1) of claim 1, wherein the magnetic field sensor (43) is shielded from interfering magnetic fields by a shielding system of the encoder system (1), the shielding system comprising at least one of the group consisting of at least one of the first discharge element (51), the second discharge element (53), and the carrier (55).

6. The encoder system (1) according to any one of claims 1 to 4, wherein the first direction is axially aligned.

7. The rotating part (15) comprises a carrier (55) made of a magnetically conductive material, the magnetic strip (47) and the at least two magnet pairs are arranged on the carrier (55), 7. The encoder system (1) according to claim 6, wherein the carrier (55) is embodied as a sleeve, the sleeve being provided to be connected in a rotatably fixed manner to the shaft (11) of the drive device.

8. The encoder system (1) according to any one of claims 1 to 4, wherein the first direction is radially aligned.

9. The rotating part (15) comprises a carrier (55) made of a magnetically conductive material, the magnetic strip (47) and the at least two magnet pairs are arranged on the carrier (55), 9. The encoder system (1) according to claim 8, wherein the carrier (55) is embodied as a disk, the disk being provided to be connected in a rotatably fixed manner to the shaft (11) of the drive device.

10. A shaft (11), An encoder system (1) according to any one of claims 1 to 6 and claim 8; An electric motor having

11. 11. Electric motor according to claim 10, wherein the shaft (11) is embodied as a hollow shaft.

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