Drive with magnetic absolute coding

Abstract

A magnetic drive (1) comprising an absolute encoder for determining the absolute position of a first body (2) of the magnetic drive (1), which is adjustable to a second body (3) of the magnetic drive (1) and moves by a position, in particular a length position, to the latter, wherein the first body (2) has sensor elements (4) for determining the absolute position from a scale (5) of the absolute encoder, and wherein the second body (3) has magnetic drive elements (9) arranged equidistantly from one another in a track plane (6) along a track direction (7), in particular equidistantly, in relation to a magnetic track (8), characterized in that the scale (5) is formed by the respective arrangement of the drive elements (9) in the track plane (6).

Description

[0001] The present invention relates to the field of magnetic absolute encoders for determining an absolute position with respect to a position, in particular a length position, of two bodies that are adjustable relative to each other. The invention is particularly applicable to linear motors, which, when using permanent magnets, constitute a special class of brushless servo motors. The linear motor does not generate a rotary motion in the driven body, but rather moves it in a straight line or along a curved path. Linear motors are therefore particularly suitable for applications requiring direct translational motion. Applications for rotary motors are also possible.

[0002] In a linear motor, the energized part of the motor can move translationally, while the electrically passive, i.e., unenergized, part remains stationary, provided the magnetic field of the stationary part is generated by a series of permanent magnets. The reaction forces exerted by the moving active part on the stationary passive part must be absorbed by the machine bed or the system. Because linear motors achieve very high accelerations and travel speeds, they are particularly well-suited for use in machine tools and positioning systems.

[0003] In general, absolute encoders are used particularly as linear or angular encoders on machine tools, in automation technology and on measuring and testing equipment.

[0004] Absolute encoders typically output the absolute position as a digital numerical value. Since this numerical value is unique across the entire measuring length or range of the absolute encoder, no initial reference run, as required for incremental encoders, is necessary. In contrast, incremental encoders measure a relative change in position based on an increment change, where an increment can be considered a basic structure of code elements belonging to a so-called measure embodiment. In this context, the measure embodiment is the representation of increment information using scannable code elements.

[0005] Incremental encoders typically count a number of increments traversed when the position changes. The relative position is only known in relation to a position at the start of the measurement, or it can be determined as absolute information through a reference run, e.g., to a stop or a reference position.

[0006] In addition to optical absolute encoders, where multiple code tracks of a scale are scanned in parallel using optoelectronic sensors, magnetic absolute encoders are often used in environments prone to contamination. With these, encoding is achieved either by evaluating the position of a rotating magnet or by evaluating a magnetic field modulated by a scale according to the vernier principle.

[0007] Furthermore, magnetic absolute encoders are known that operate according to the code principle. Here, the code elements are designed as magnetic dipoles, whereby, depending on the orientation of a respective code element in the scale, a north pole or a south pole is scanned, thus defining a binary code. At each angular or longitudinal position of the absolute encoder, several code elements are scanned simultaneously, with the encoding along the scale being chosen such that each bit pattern scanned at a specific position is unique.

[0008] German patent application DE 10 2018 118 477 A1 describes a magnetic absolute encoder for determining the absolute position of two bodies mounted to be displaceable or rotatable relative to each other by a linear or angular position. The application discloses a scale defining the absolute track, which comprises a plurality of magnetic code elements. A magnetic field sensor arrangement scans the magnetic scale formed by the code elements. DE 10 2018 118 477 A1 proposes the absolute encoding in which each of the first code elements of the scale is offset by a respective encoding offset from a virtual reference position assigned to that first code element, wherein the reference position is equidistant and without offset along the absolute track. This means that the code elements are arranged offset in or against the direction of movement of the bodies.Patent EP 2 404 142 B1 alternatively proposes the use of notches to form a physical embodiment, which are positioned parallel to each other in the direction of movement of a body moving over the physical embodiment and which differ in their notch depth or notch width and can thus encode a position of the moving body.

[0009] The principle of the proposed encodings is based on the fact that the physical embodiment generates a magnetic stray field or influences a stray field of an externally generated magnetic field.

[0010] The absolute track is arranged in the direction of an adjustment direction, or the direction of movement of a body, i.e., circularly or linearly. The coding offset of the coding elements proposed in DE 10 2018 118 477 A1 occurs exclusively in the direction of the absolute track, i.e., along the linear or circular direction of movement of the body or perpendicular to it, i.e., into or out of the plane of movement of the body. In one embodiment, the coding elements are offset into or out of the plane of movement of the body, or shifted downwards or upwards relative to it. In contrast, DE 10 2018 118 477 A1 teaches an arrangement of the coding elements without offset transversely to the direction of movement of the body, i.e., an equidistant and uniform arrangement of the coding elements transversely to the track direction. Instead, the coding elements are offset into or out of the plane of movement.

[0011] Both the absolute track described in EP 2 404 142 B1 and the one described in DE 10 2018 118 477A1 constitute an additional track to the drive track of a drive. This means that the absolute track and its code elements must be attached to a corresponding drive along with the sensors. This attachment requires additional effort and, in particular, additional space for the encoder's physical dimensions during the drive's manufacture. Furthermore, it increases the drive's cost. Consequently, attaching the absolute encoder to a finished drive involves a complex modification.

[0012] It is therefore an object of the invention to provide a magnetic drive with an absolute encoder, wherein the encoder requires only a small additional space in the drive and, in particular, no additional measuring instrument is required to determine the absolute position of the moving body.

[0013] The problem is solved by the magnetic drive with an absolute encoder according to claim 1. Further embodiments are the subject of the dependent claims.

[0014] The magnetic drive according to the invention has an absolute encoder for determining an absolute position of a first body of the magnetic drive, which is adjustable to a second body of the magnetic drive and is moved by a position, in particular a length position, wherein the first body has sensor elements to determine the absolute position from a dimension of the absolute encoder and wherein the second body has magnetic drive elements arranged equidistantly from one another in a track plane along a track direction, characterized in that the dimension is formed by the respective arrangement of the drive elements, in particular transverse to a track direction, in the track plane.

[0015] The measuring instrument is designed in particular by arranging the drive elements in the track plane of the magnetic track, at least partially offset from one another perpendicular to a track direction. This creates coding areas that exhibit distinguishable field strengths or signal strengths when detected by sensor elements of the first body. The measured signal or field strengths are transmitted to an evaluation unit and converted into absolute position data. The evaluation unit can also convert measured field strengths into incremental position data.

[0016] Since the arrangement of the drive elements, particularly perpendicular to the track direction in the track plane, forms the standard dimension, the absolute encoder of the magnetic drive does not require an additional standard dimension, i.e., no standard dimension designed as a separate component. This advantageously reduces the space required for the encoder to determine the absolute position. Furthermore, the manufacturing process of the drive with the absolute encoder is simplified, as no additional coding elements are needed. Instead, by arranging the drive elements in the plane of the magnetic track, perpendicular to the track direction (i.e., in a direction essentially perpendicular to the track direction), coding areas are formed as coding elements, for example, at the edge of the magnetic track. These coding areas together constitute the standard dimension.Thus, the absolute value encoding of the absolute encoder can be implemented with minimal technical effort simply by arranging the drive elements. The arrangement could, for example, result solely from the manufacturing tolerances in the arrangement and positioning of the drive elements. Preferably, an incremental dimensioning, in addition to an absolute one, can be implemented by the arrangement of the drive elements themselves, particularly an equidistant one, along the magnetic track.

[0017] In this context, a track plane is understood to be the plane resulting from the arrangement of the drive elements of the second body, along or within which the first body essentially moves. In the case of a linear drive, this plane can essentially be a surface, i.e., a planar, flat geometric surface. Alternatively, in the case of a rotary drive, the plane can be the lateral surface of a cylinder, on which the first body essentially rotates around the second body.

[0018] In this context, the term "track direction" refers to the direction in which the drive elements are aligned to form the track plane or magnetic track. Thus, the track direction corresponds to the direction in which the first body moves relative to the second body. With a linear drive, the track direction is essentially straight, while with a rotary drive, the track direction can be circular, for example, running around the track plane, which is defined as a lateral surface.

[0019] In this context, an arrangement essentially refers to the positioning of the drive elements relative to a magnetic track. The drive elements are arranged along the track direction relative to a track plane, preferably parallel and particularly preferably equidistant from one another, so that the magnetic interaction of the drive elements with elements of the first body moves the latter along the magnetic track. The arrangement can have an offset between the drive elements, thereby forming coding areas of the scale.

[0020] In this context, a dimensional representation refers to the components of the absolute encoder that allow the precise position or value of a measured parameter to be encoded. In a linear absolute encoder, the position is measured along a straight line. The dimensional representation can be, for example, a ruler or a measuring tape marked with markings or codes that uniquely identify the position. In a rotary absolute encoder, the angular position is measured. The dimensional representation can be a circular coding strip or a ring mounted on the encoder's pivot point, displaying absolute values ​​for various positions. In this case, the dimensional representation is formed by the arrangement of the drive elements. Depending on the arrangement and design of these drive elements, coding areas are created at the edge or within the drive elements or the magnetic track.The encoding areas are thus part of the magnetic track, and the entirety of the encoding areas can form one or more scales. For example, one scale can be formed at the edge and another in a central area of ​​the magnetic track by the arrangement and design of the drive elements, particularly if the drive elements are partially designed as multi-part drive elements.

[0021] In a particularly preferred embodiment of the magnetic drive, the drive elements are arranged in the track plane of the magnetic track, transverse to the track direction, in particular parallel to each other, at least partially by a respective offset from each other, so that the respective offset forms a respective coding area of ​​the drive element of the magnetic track and the drive elements are arranged in the magnetic track in such a way that the coding areas form the scale at the edge of the magnetic track.

[0022] By arranging the drive elements at least partially offset from one another, a first and a complementary second scale are formed, particularly on two sides of the magnetic track, especially with rectangular drive elements. This has the advantage that the accuracy of the absolute position is higher through the combined evaluation of both position data than with only one scale.

[0023] The drive elements are preferably displaced or offset from other drive elements in the track plane, either transversely or perpendicularly to the track direction, with respect to a virtual reference position, i.e., with respect to an imaginary line along the track direction. This reference position can be defined by the track direction. The respective offset is preferably the same for all displaced or shifted drive elements with respect to the reference position; that is, displaced drive elements are arranged offset from each other by an amount equal to that of a reference position. This offset creates coding areas. If the offset is the same for all drive elements, the coding areas are essentially the same size.On the one hand, the offset leads directly to the formation of a coding area in the drive element that is offset; on the other hand, the offset also makes areas of non-offset or offset drive elements coding areas of the dimension that forms as a result of the offset in the magnetic track along the track direction.

[0024] A drive element can be offset relative to a reference position from, for example, an adjacent drive element such that the coding area of ​​the offset drive element is formed by an edge or end section of the drive element. The coding area of ​​the unoffset drive element is then represented, or formed, by an area immediately adjacent to the edge or end section of the drive element. This corresponds to an area in which essentially no part or section of the drive element is located. That is, this coding area lies essentially outside of a drive element. Thus, the coding area of ​​the offset drive element exhibits a certain field strength that essentially corresponds to that of the drive element, while the coding area of ​​the unoffset drive element, in comparison, exhibits only a low field strength, which is essentially defined by the area outside the edge, i.e.,the outer area of ​​the drive element. Digital values, i.e., 0 or 1, can be assigned to the resulting different field strengths of adjacent coding areas. The coding areas form a coding along an edge of the magnetic track, acting as a physical measure. The offset can also be configured in steps such that more than just two digital values, i.e., -1 0 1 or 0 1 2, can be assigned to the resulting field strengths of adjacent coding areas.

[0025] A drive element has at least one coding area. The coding area of ​​a drive element can be located in an area around the drive element.

[0026] In this context, a coding area is understood to be the area of ​​a drive element that acts like a coding element of a physical dimension and thus forms a respective part of that dimension. A drive element can have multiple coding areas. A coding area can correspond to the central area of, for example, a rectangular drive element, or to the edge area or an end section of the drive element. A coding area can also lie outside the end section of the drive element.

[0027] The resulting different coding areas are distinguishable by their magnetic field strength. The coding areas are distinguishable in such a way that a digital value of 0 or 1 can be uniquely assigned to them when a sensor element measures the field strength of the coding area. In a drive element consisting of two or more parts, coding areas are created in the spaces between the respective parts of the drive element. In these intermediate spaces, the magnetic flux is lower than in the remaining, undivided areas of the drive element. A coding area can, in principle, be formed by any area of ​​a drive element, as long as the area can be distinguished from the magnetic flux or field strength of another area. For example, the edge area, i.e.,A first coding area with a lower field strength is formed in a region essentially outside the end section of a drive element, and a second coding area is formed through the center of the same drive element. Since a higher field strength is present in the center of the drive element, the two coding areas are distinguishable from each other.

[0028] In a particularly preferred embodiment of the magnetic drive, the drive elements in the track plane of the magnetic track have a respective length as an offset, transverse to the track direction, such that the respective length forms a respective coding area of ​​the drive element of the magnetic track and the drive elements are arranged relative to each other in the magnetic track in such a way that the coding areas form the dimension at the edge of the magnetic track.

[0029] In this embodiment, the drive elements are offset by being at least partially shorter or longer than other drive elements of the magnetic track. Thus, the different lengths of the drive elements, for example in the case of rectangular drive elements, result in a scale only at one edge of the magnetic track. The opposite edge of the magnetic track can advantageously be used as an incremental scale.

[0030] In a particularly preferred embodiment of the magnetic drive, the drive elements in the track plane of the magnetic track are formed in multiple parts and the respective parts have an offset transverse to the track direction, so that the offsets of the respective parts form respective coding areas of the drive element and the drive elements are arranged relative to each other in the magnetic track in such a way that several scales are formed in the magnetic track by the coding areas.

[0031] Since the individual parts of the drive elements are offset from or spaced apart from each other, the field strength is lower in the areas between the parts than in the other areas. Thus, the areas between the parts are digitally distinguishable from the other areas, meaning that a value of 1 for a high field strength or 0 for a measurably lower field strength can be uniquely assigned to each area. This results in coding areas in the spaces between the parts and the other areas. In this embodiment, particularly with rectangular drive elements, several physical dimensions can advantageously form within the magnetic track due to the spacing between the parts of a drive element. This increases the accuracy of the position determination.

[0032] In a particularly preferred embodiment of the magnetic drive, the drive elements are formed in two parts in the track plane of the magnetic track, and the first part of the drive element has a distance, i.e. an offset, to the second part transversely to the track direction, so that a coding area is formed in the drive element by the offset, and the drive elements are arranged to each other in the magnetic track in such a way that two complementary scales are formed in the magnetic track by the coding areas.

[0033] In this particularly preferred embodiment, especially with rectangular drive elements, a first and a second complementary scale are formed, which run within the magnetic track and not at its edge. This has the advantage that the accuracy of the absolute position is higher through the combined evaluation of both position data than with only one scale. Furthermore, the edges of the magnetic track can be used as additional incremental scales.

[0034] In a preferred embodiment of the magnetic drive, the first body has at least N sensor elements whose arrangement in the track plane along the track direction is adapted to the arrangement of the drive elements, so that in positions of the first body a sensor element of the N sensor elements is arranged over the coding area of ​​a respective drive element of the drive elements.

[0035] In this context, "aligned" means that the respective sensor elements of the N sensor elements do not have to be arranged exactly above the coding area of ​​a respective drive element in the multiple positions of the first body, i.e., they do not have to be equidistant from each other, but can have a distance that varies from sensor element to sensor element.

[0036] In a particularly preferred embodiment of the magnetic drive, the first body has at least 2N sensor elements whose arrangement in the track plane along the track direction is aligned with the arrangement of the drive elements, so that in positions of the first body two sensor elements of the 2N sensor elements are arranged above the coding area of ​​a respective drive element of the drive elements.

[0037] In a particularly preferred embodiment of the magnetic drive, the first body has at least 2N sensor elements whose arrangement in the track plane along the track direction is adapted to the arrangement of the drive elements, so that in positions of the first body one sensor element of the 2N sensor elements is arranged over one of the coding areas of a respective drive element of the drive elements.

[0038] This can improve the accuracy of the position determination, as the doubled number of position data points allows, for example, averaging.

[0039] In a particularly preferred embodiment of the magnetic drive, the first body has at least 4N sensor elements whose arrangement in the track plane along the track direction is adapted to the arrangement of the drive elements, so that in positions of the first body two sensor elements of the 4N sensor elements are arranged over each of the coding areas of a respective drive element of the drive elements.

[0040] This improves the accuracy of position determination. Firstly, because doubling the number of position data points allows for averaging, for example. Secondly, because position data from different units of measurement can be used for position determination, especially position data from complementary units of measurement.

[0041] In a preferred embodiment of the magnetic drive, N successive coding areas each form a respective codeword of the scale and each codeword along the magnetic track is unique and represents an absolute position.

[0042] In this context, with respect to a binary encoding, R = 2 defines the binary states 0 or 1. The maximum size of a spatial encoding offset is limited by the distance between two immediately adjacent relative positions. A number N of code elements can be simultaneously detected by the sensor elements as a codeword, such that R N Various positional information can be evaluated by the absolute encoder to determine the absolute position. N, for example, can have a value, i.e., a bit depth of 7, 8, 10, or 11 characters.

[0043] In a preferred embodiment of the magnetic drive, the entirety of the character string encoded by the coding areas of the scale is designed as a pseudo-random binary sequence code (PRBS code).

[0044] In a particularly preferred embodiment of the magnetic drive, the drive elements are designed as permanent magnets and / or as magnetic coils.

[0045] In a particularly preferred embodiment of the magnetic drive, the drive is designed as a linear drive and includes an evaluation unit which is configured to read and process sensor data from the sensor elements in order to calculate the absolute position of the first body from the sensor data, wherein the magnetic drive elements of the second body interact magnetically with magnetic drive elements of the first body to drive the first body. Fig. Figure 1 shows a schematic representation of an embodiment of the magnetic drive according to the invention with a first and second body, wherein the first body moves along a magnetic track of the second body. Fig. Figure 2a shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention with sensor elements for scanning the coding areas. Fig. Figure 2b shows a schematic view of a section of the magnetic track with four drive elements shown in different arrangements. Fig. Figure 3 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention, with two sensor elements each for scanning the coding areas. Fig. Figure 4 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention with two sensor elements for scanning the coding areas and two adjacent scales. Fig. Figure 5 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention, wherein an offset of the drive elements results from the fact that the drive elements have partially different lengths. Fig. Figure 6 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention, wherein the coding areas are formed by two-part drive elements within the magnetic track. Fig. Figure 7 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention, wherein the coding areas are partly formed by two-part drive elements within the magnetic track and partly by drive elements that have different lengths. Fig. Figure 8 shows a schematic representation of an embodiment of the magnetic track of the magnetic drive according to the invention, wherein the coding areas are partly formed by two-part drive elements within the magnetic track and partly additionally arranged offset from each other.

[0046] In Fig. Figure 1 is a schematic representation of an embodiment of the magnetic drive 1 according to the invention, comprising a first body 2 and a second body 3, wherein the first body 2 moves along a magnetic track 8 of the second body 3 in the track direction 7. The magnetic track 8 is formed in the track plane 6. The magnetic track 8 has several drive elements 9 arranged parallel to one another. The drive elements are displaced section by section in a direction 13 transverse to the track direction 7, so that an offset 11 is formed at the respective edges 15 of the magnetic track 8. The offset 11 results in coding areas 12 at the two edges 15 of the magnetic track 8. The coding areas 12 form a respective dimension 5 at a respective edge 15 of the magnetic track 8. The edge 15 appears frayed due to the offset 11 of the drive elements 9 at the edges 15.The coding areas 12 resulting from the offset 11 are characterized by the fact that they are formed by an end section or an edge of a rectangular drive element 9, or by the fact that there is no longer a drive element 9 in the coding area 12, i.e., the coding area 12 is essentially located outside the drive element 9. The coding areas 12 therefore correspond to areas that differ by a high field strength and a correspondingly lower field strength, so that when the field strength in a coding area 12 is measured by a sensor element 4 of the first body 2, at least one first or one second field strength is obtained, and this can be uniquely assigned to a digital value. Thus, the coding areas 12 act as code elements of the physical embodiment 5 of the drive 1. Fig. The first body 2 comprises a total of four sensor elements 4, which are designed to measure the field strength in a respective coding area 12 when the body 2 is moving or when the body 2 is stationary. The sensor elements 4 are arranged in Fig. The sensor elements 4 are spaced apart from each other such that each sensor element 4 can be positioned over a respective coding area 12 of a drive element 9 in order to measure its field strength. The offset 11 occurs in the plane of the track direction 7 in a substantially perpendicular direction, or in a direction transverse to the track direction 7.

[0047] In Fig. Figure 2a shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, with six sensor elements 4 for scanning the coding areas 12. The embodiment of the magnetic track 8 corresponds to a top view of the Fig. 1. Magnetic track 8 shown. At an edge region 15 of the magnetic track 8, the six sensor elements 4 of the first body 2 (not shown) are positioned such that the sensor elements 4 are arranged over a respective coding area 12 of the drive elements 9. The coding areas 12 result from the parallel offset 11 of the drive elements to each other and transversely to the track direction 7. The coding is achieved by the fact that only certain drive elements 9 move to a virtual reference position, which is defined by the Fig. 2a, the indicated track direction 7 can actually be offset, and the resulting field strength modulation at the edge 15 of the magnetic track 8 corresponds to the desired encoding. It can be specified that a encoding area 12 with a low field strength, as in Fig. 2a indicates that a digital value of 0 corresponds to a coding area with a correspondingly higher field strength corresponds to a digital value of 1. This results in the following: Fig. 2. The bit pattern 010010, which corresponds to an absolute position of the scale 5, is shown when reading the six sensor elements 4 arranged over the coding areas 12. The polarization or the “N”, “S” direction of the magnetic fields of the drive elements 9 is shown out of or into the plane of the drawing, so that only the “S” or “N” polarization is visible for each drive element 9 in this representation.

[0048] In Fig. Figure 2b shows a schematic view of a section of the magnetic track 8 with four drive elements 9. The drive elements 9 are shown in four different arrangements in the track plane 6. By offsetting them 11, a total of two scale dimensions 5 are obtained, each indicated by dashed lines.

[0049] The first drive element 9 on the left has no offset 11. The second and fourth drive elements 9 from the left are offset from the reference track 17, which corresponds to the track direction 7, by the offset 11. Due to the offset 11, two coding areas 12 are formed outside the drive elements 9 at the edge 15 of the magnetic track 8, each indicated by dashed circles. As a result, the edge areas or end sections 18 of the drive elements 9 not offset from the reference position 17, i.e., the first and third drive elements 9 from the left, also act as coding areas 12. In other words, the offset 11 of a drive element 9 leads to the formation of a coding area 12 of the drive element 9 and to the formation of coding areas 12 of other drive elements, so that a dimension 5 results from the number of formed coding areas 12. For example, the in Fig. 2b from the left, the third drive element is divided into a first 16a and a second 16b part. The parts 16a and 16b are offset from each other by the offset 11, thus forming a coding area 12 between the first 16a and second 16b part. This defines the further in Fig. 2b drawn coding areas 12 of the first, second and fourth drive elements 9 from the left, so that from the coding area 12 of one drive element 9 created by the offset 11 and the resulting coding areas 12 of the other drive elements 9 a dimension 5 results which runs in the middle area of ​​the magnetic track 8.

[0050] In Fig. Figure 3 shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, in which the coding areas 12 are scanned by two sensor elements 4 each. This allows the accuracy of the position determination to be increased, for example, by averaging. In this case, the first body 2 comprises 2N sensor elements compared to the one in Figure 3. Fig. 1 and Fig. 2. The embodiment of the first body shown is shown in section 2. For further description, see reference to... Fig. 2 referred to. The drive elements 9 are preferably equidistant from each other in the track direction 7.

[0051] In Fig. Figure 4 is a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, with two sensor elements 4 each for scanning the coding areas 12 and two mutually adjacent scales 5. Due to the offset 11 in a direction 13 transverse to the track direction 7, two mutually complementary scales 5 are formed at the edges 15 of the magnetic track 8. Accordingly, the first body 2 has four N sensor elements for scanning the coding areas 12 formed by the offset 11 at each edge 15 of the magnetic track 8. The scanning is thus carried out with two sensor elements 4 per scale. A complementary scale 5 allows for a more precise determination of the absolute position. The sensor elements can, for example, be designed as Hall sensors for determining the magnetic field strength of a coding area 12.

[0052] In Fig. Figure 5 shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, in which an offset 11 of the drive elements 9 results from the fact that the drive elements 9 differ in their length 14. Due to the different lengths 14 of the drive elements 9, one edge 15 of the magnetic track 8 is flush, while the dimensional representation 5 is formed on the opposite edge 15 by the coding areas 12. The in Fig. The 5 inscribed sensor elements 4 of the first body 2 are positioned over the coding areas 12 and detect the indicated bit sequence 010010. The flush-mounted edge 15 can be used as an incremental track in this embodiment.

[0053] In Fig. Figure 6 shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, wherein the coding areas 12 are formed by two-part drive elements 9 within the magnetic track 8. In this embodiment, the offset 11 results from the distance between a first 16a and a second 16b part of a drive element 9. The respective parts 16a, 16b are offset transversely to the track direction 7, which is indicated by a dashed arrow 13. Fig. 6 is indicated. Due to the distances between the respective parts 16a, 16b of the drive elements 9, two scales 5 are formed within the magnetic track 8 when the drive elements 9 are as shown. Fig. 6, for example, can be arranged section by section, alternating between them, i.e., each section rotated by 180° relative to the other, successively to form a magnetic track 8. This has the advantage that, through the rotation or the point symmetry of two drive elements 9 relative to each other, a first and a second, complementary dimension 5 are formed. In this embodiment, the flush-fitting edges 15 of the magnetic track 8 can additionally be used as incremental dimension 5. Of the in Fig. In the 6 inscribed 24 sensor elements 4 of the first body 2, 2 sensor elements are each positioned over a coding area 12 of a respective dimension 5 and detect the indicated bit sequence 010010, or the complementary bit sequence 101101. The flush-mounted edge 15 can be used as an incremental track in this embodiment.

[0054] In Fig. Figure 7 shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, wherein the coding areas 12 are formed partly by two-part drive elements 9 within the magnetic track 8 and partly by drive elements 9 having different lengths 14. The respective parts 16a, 16b are offset transversely to the track direction 7, which is indicated by a dashed arrow 13 in Fig. 7 is indicated. In this embodiment, the partially two-part construction of the drive elements 9, with a first 16a and second 16b part, results in a first dimension 5 essentially in the middle of the magnetic track 8. The additional, partially differing length 14 of the drive elements 9 results in a further dimension 5 at an edge 15, complementary to the first. The opposite, flush-mounted edge 15 can be used as an incremental dimension. The sensor elements 4 of the first body 2, positioned over the respective coding areas 12, would therefore define the dimensions in the Fig. 7. Measure the first bit sequence shown, 101101, or the complementary bit sequence 010010.

[0055] In Fig. Figure 8 shows a schematic representation of an embodiment of the magnetic track 8 of the magnetic drive 1 according to the invention, wherein the coding areas 12 are partially formed within the magnetic track 8 by two-part drive elements 9 16a, 16b and are additionally arranged partially offset from one another 11. In this embodiment, the respective arrangements of the drive elements 9, i.e., the offset 11 between a first 16a and second 16b part of a drive element, create a first dimension 5, which runs essentially in the middle of the magnetic track 8. Two further dimension 5 result from the partial offset 11 of the drive elements 9 from one another at the respective edges 15 of the magnetic track 8. The sensor elements 4 of the first body 2 are arranged over the respective coding areas 12 of the respective dimension 5, so that a bit sequence of M measured at the first edge 15 is generated. R1This would result in 010010. A bit sequence of M measured at the opposite edge, 15 in total. R2 101101 and the following bit sequence in the medium scale 5M M 010010. The bit sequences M R1 and M R2 The respective edges 15 are complementary bit sequences to each other, thus increasing the accuracy of the position measurement. The offset 11 between the drive elements, or between the first 16a and second 16b parts of the drive elements 9, is offset perpendicular to the track direction 7 and is indicated by a dashed arrow 13. Fig. 8 indicated. List of reference symbols 1 Magnetic drive 2 First body 3 Second Body 4 sensor elements 5. Embodiment of measurement 6 lane level 7 lane direction 8 magnetic track 9 drive elements Section 10 11 Offset 12 Coding area 13 Direction perpendicular to the lane direction 14 Length 15 Rand 16a first part of a drive element 16b second part of a drive element 17 Reference position 18 End section of a drive element QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 118 477 A1 [0008, 0010, 0011] EP 2 404 142 B1 [0008, 0011]

Claims

[1] Magnetic drive (1) comprising an absolute value encoder for determining an absolute position of a first body (2) of the magnetic drive (1), which is adjustable relative to a second body (3) of the magnetic drive (1) by a position, in particular a length position, relative to the latter, wherein the first body (2) comprises sensor elements (4) for determining the absolute position from a measuring embodiment (5) of the absolute value encoder, and wherein the second body (3) comprises magnetic drive elements (9) arranged in a track plane (6) along a track direction (7), in particular equidistantly, spaced from one another to form a magnetic track (8), characterized by that the measuring embodiment (5) is formed by the respective arrangement of the drive elements (9) in the track plane (6). [2] Magnetic drive according to claim 1, characterized bythat the drive elements (9) are arranged in the track plane (6) of the magnetic track (8), transversely (13) to the track direction (7), in particular parallel to one another, at least partially by a respective offset (11) to one another, so that the respective offset (11) forms a respective coding region (12) of the drive element (9) of the magnetic track (8) and the drive elements (9) are arranged relative to one another in the magnetic track (8) such that the measuring embodiment (5) is formed on an edge (15) of the magnetic track (8) by the coding regions (12). [3] Magnetic drive according to claim 1 or 2, characterized bythat the drive elements (9) in the track plane (6) of the magnetic track (8), transversely (13) to the track direction (7), have a respective length (14) as an offset (11), so that the respective length (14) forms a respective coding region (12) of the drive element (9) of the magnetic track (8) and the drive elements (9) are arranged relative to one another in the magnetic track (8) such that the measuring embodiment (5) is formed on an edge (15) of the magnetic track (8) by the coding regions (12). [4] Magnetic drive according to one of claims 1 to 3, characterized bythat the drive elements (9) are designed in several parts in the track plane (6) of the magnetic track (8) and the respective parts (16a, 16b) have an offset (11) transversely (13) to the track direction (7), so that the offsets of the respective parts (16a, 16b) form respective coding areas (12) of the drive element (9) and the drive elements (9) are arranged relative to one another in the magnetic track (8) such that a plurality of measuring embodiments (5) are formed in the magnetic track (8) by the coding areas (12). [5] Magnetic drive according to claim 1, characterized bythat the drive elements (9) are designed in two parts in the track plane (6) of the magnetic track (8) and the first part (16a) has an offset (11) to the second part (16b) transversely (13) to the track direction (7), so that a coding area (12) is formed in the drive element (9) by the offset (11) and the drive elements (9) are arranged relative to one another in the magnetic track (8) such that two complementary measuring embodiments (5) are formed in the magnetic track (8) by the coding areas (12). [6] Magnetic drive according to one of claims 2 to 5, characterized by that the first body (2) has at least N sensor elements (4), the arrangement of which in the track plane (6) along the track direction (7) is adapted to the arrangement of the drive elements (9), so that in positions of the first body (2) one sensor element (4) of the N sensor elements (4) is arranged above the coding area (12) of a respective drive element (9) of the drive elements (9). [7] Magnetic drive according to one of claims 2 to 5, characterized by that the first body (2) has at least 2N sensor elements (4), the arrangement of which in the track plane (6) along the track direction (7) is adapted to the arrangement of the drive elements (9), so that in positions of the first body (2) two sensor elements (4) of the 2N sensor elements (4) are arranged above the coding area (12) of a respective drive element (9) of the drive elements (9). [8] Magnetic drive according to one of claims 2 to 5 characterized by that the first body (2) has at least 2N sensor elements (4), the arrangement of which in the track plane (6) along the track direction (7) is adapted to the arrangement of the drive elements (9), so that in positions of the first body (2) one sensor element (4) of the 2N sensor elements (4) is arranged above one of the coding areas (12) of a respective drive element (9) of the drive elements (9). [9] Magnetic drive according to one of claims 2 to 5 characterized by that the first body (2) has at least 4N sensor elements (4), the arrangement of which in the track plane (6) along the track direction (7) is adapted to the arrangement of the drive elements (9), so that in positions of the first body (2) two sensor elements (4) of the 4N sensor elements (4) are arranged above one of the coding areas (12) of a respective drive element (9) of the drive elements (9). [10] Magnetic drive according to one of the preceding claims, characterized by that R successive coding areas (12) form a respective code word of the measuring embodiment (5) and each code word along the magnetic track (8) is unique and represents an absolute position. [11] Magnetic drive according to one of the preceding claims, characterized bythat the entirety of the character sequence encoded by the coding areas (12) of the measuring embodiment (5) is designed as a pseudo-random binary sequence code (PRBS code). [12] Magnetic drive according to one of the preceding claims, characterized by that the drive elements (9) are designed as permanent magnets and / or as magnetic coils. [13] Magnetic drive according to one of claims 1 to 12, characterized by that the drive (1) is designed as a linear drive and comprises an evaluation unit which is set up to read out and process sensor data of the sensor elements (4) in order to calculate the absolute position of the first body (2) from the sensor data, wherein the magnetic drive elements (9) of the second body (3) magnetically interact with magnetic drive elements (9) of the first body (2) for driving the first body (2).

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