POSITION MEASURING DEVICE WITH PERMANENT MAGNETS

Description

FIELD OF TECHNOLOGY

[0001] The invention relates to a position measuring device for measuring a relative angular or linear position between a detection and scale element using permanent magnets according to claim 1. STATE OF THE ART

[0002] Patent EP 2 053 362 A2 discloses a position measuring device comprising one absolute and two incremental graduation tracks. Magnetoresistive sensors enable the determination of position information, particularly by using three stacked bias elements with differentiating polarization directions. A disadvantage of the prior art position measuring device is the higher material and assembly costs due to the use of three bias elements. SUMMARY OF THE INVENTION

[0003] The invention is based on the object of creating a position measuring device which combines high measuring accuracy and economical production.

[0004] This object is achieved according to the invention by the features of claim 1. Advantageous embodiments and further developments are specified in the respective dependent claims.

[0005] The position measuring device according to the invention comprises a detection element, such as a scanning head of an angle or length measuring device, and a scale element movable relative to the detection element along a first direction (x), for example a magnetic graduation drum or measuring tape of an angle or length measuring device. The scale element has a first and a second graduation track, both of which are absolute, as well as a third incremental graduation track, wherein the three graduation tracks run or are arranged parallel to one another and spaced apart in a second direction (y). The detection element comprises at least one first sensor field, which is arranged offset in a third direction (z) relative to the first graduation track, such that a third air gap is formed between the first sensor field and the first graduation track.The detection element further comprises a second sensor field, which is arranged offset in the third direction (z) with respect to the second graduation track. The third air gap is formed between the second sensor field and the second graduation track. The detection element further comprises a third sensor field, which is arranged offset in the third direction (z) with respect to the third graduation track, such that the third air gap is also formed between the third sensor field and the third graduation track. The magnetically sensitive sensor fields are designed and arranged such that at least the magnetically designed graduation track opposite the respective sensor field in the third direction (z) can be scanned. In addition, the detection element comprises a first permanent magnet, for example in the form of a cuboid bar magnet.The first permanent magnet is arranged opposite the first graduation track and offset therefrom in the third direction (z) such that the first sensor field is arranged between the first permanent magnet and the first graduation track. A second air gap can be formed between the first sensor field and the first permanent magnet. A second permanent magnet, for example in the form of a cuboid bar magnet, is arranged opposite the second graduation track and offset therefrom in the third direction (z). The second permanent magnet is also arranged offset in the third direction (z) such that the second sensor field lies between the second graduation track and the second permanent magnet. The second air gap can also be formed between the second sensor field and the second permanent magnet. In addition, a first air gap can be formed in the second direction (y) between the first and second permanent magnet.

[0006] The sensor fields are therefore arranged offset in a third direction (z) to the respective graduation track to be scanned and are arranged opposite to the respective graduation track to be scanned.

[0007] The first and second graduation tracks are absolute, meaning that the detection element always determines the current absolute position value as soon as the position measuring device is in operation. In addition, the detection element scans the third incremental graduation track, thereby determining a comparatively fine incremental position. To increase resolution and measurement accuracy, the absolute position value is linked to the incremental position. The three graduation tracks run parallel to each other along the first direction (x) and are spaced apart from each other in a second direction (y).

[0008] In this way, the position measuring device according to the invention achieves a high measuring accuracy, in particular by minimizing measurement deviations such as interpolation or reversal errors.

[0009] An air gap is the space or distance between two opposing surfaces capable of conducting a magnetic flux. In addition to air, the air gap can also contain any other solid, gas, gas mixture, or combination thereof that interacts almost non-ferromagnetically, such as an aluminum alloy. The first, second, and third air gaps can also be made of different materials. For example, the first and second air gaps can be made of an aluminum alloy, and the third air gap can be made of air.

[0010] The sensor fields used in the position-measuring device according to the invention are designed as magnetically sensitive structures applied to one and the same flat substrate (e.g., a glass substrate). Alternatively, a separate flat substrate can be provided for each sensor field. These sensor fields can consist of several ferromagnetic metal strips, for example, made of permalloy. The magnetic fields of the scale element influence the magnetization of the metal strips, thereby changing the electrical resistance (magnetoresistive effect). These position-dependent resistance values ​​are output as position information after electronic processing of the sensor signals generated by the sensor fields in an evaluation electronics.

[0011] Due to the magnetic field B of the two permanent magnets, the sensor fields experience a defined pre-magnetization, which counteracts the formation of magnetic domains in the metal strips.

[0012] The coordinate system described here is a Cartesian coordinate system, ie the first direction (x) is orthogonal to the second direction (y) and the third direction (z) is in turn oriented orthogonally to the other two directions (x and y).

[0013] According to an advantageous development of the invention, the third graduation track can be arranged between the first graduation track and the second graduation track with respect to the second direction (y). This is advantageous because the two permanent magnets, which are offset from the first and second graduation tracks in the third direction (z), can exert a premagnetization with respect to all sensor fields used in the detection element. An additional permanent magnet above the third graduation track or the third sensor field is not required.

[0014] According to the invention, the scale element is formed by a method in which a magnetic material is applied into or onto the surface of a support element, for example, a metal support element with a rectangular cross-sectional shape. The graduation tracks can then be generated by local magnetization according to a predetermined, precise pattern.

[0015] Advantageously, the position measuring device is configured such that the magnetization direction of the two permanent magnets is identical, which can lead to the formation of a magnetic field with a homogeneous component in at least one plane of the first and second direction (x,y planes) above and / or below and / or between the two permanent magnets, for example with an offset of the permanent magnets in the second direction (y).

[0016] The magnetization direction of the two permanent magnets can be configured such that the north pole of the first permanent magnet and the south pole of the second permanent magnet are opposite each other. Alternatively, the south pole of the first permanent magnet and the north pole of the second permanent magnet can also be opposite each other.

[0017] A homogeneous region is understood to be at least a partial region of a magnetic field in which the field lines in at least one plane (for example the x,y plane) all run parallel and in the same direction (for example in the y direction).

[0018] Alternatively and according to a third embodiment, the third sensor field can be arranged such that it still lies in a homogeneous region of the magnetic field B between the first and second permanent magnets, but without lying in a plane (x,y plane) with the first and second sensor fields.

[0019] The two permanent magnets can be arranged parallel to each other so that the pole orientation of the permanent magnets (direction of the connecting line between the north and south poles) each has a directional component perpendicular to the measuring direction (x-direction). In particular, the longitudinal edges of the two permanent magnets can run along the measuring direction (x-direction). The sensor fields can also be arranged parallel to each other in the measuring direction (x-direction) so that their longitudinal edges run along the measuring direction (x-direction). Advantageously, the secondary edges, which define the height of the permanent magnets or sensor fields, run parallel to the third direction (z). The secondary edges, which define the width of the permanent magnets or sensor fields, can run parallel to the second direction (y).

[0020] In a further embodiment, the first permanent magnet can be offset from the first graduation track in the third direction (z) such that the first sensor field lies between the first graduation track and the first permanent magnet with respect to the third direction (z). Additionally or alternatively, the second permanent magnet can be offset from the second graduation track in the third direction (z) such that the second sensor field lies between the first graduation track and the second permanent magnet with respect to the third direction (z). Advantageously, one permanent magnet is positioned centrally above each sensor field.

[0021] According to a further embodiment, a second air gap can be formed between the first permanent magnet and the first sensor field in the third direction (z). Additionally or alternatively, a second air gap can be formed between the second permanent magnet and the second sensor field in the third direction (z). The first permanent magnet and the second permanent magnet can lie in one plane (x,y plane). The first sensor field and the second sensor field can also lie in a further plane (x,y plane), so that the second air gap in the third direction (z) is identical between the first sensor field and the first permanent magnet and between the second sensor field and the second permanent magnet.

[0022] In a further embodiment of the invention, the first permanent magnet can be arranged on the back of the substrate above the first sensor field. Similarly, the second permanent magnet can be arranged on the back of the substrate above the second sensor field. In this embodiment, there is therefore no second air gap between the substrate of the first sensor field and the first permanent magnet, and additionally or alternatively between the substrate of the second sensor and the second permanent magnet. Nevertheless, a detachable or fixed connection, for example, an adhesive connection, can be provided between a permanent magnet and the substrate.

[0023] The back side of the substrate is understood to mean the part of the substrate surface which lies opposite the surface in the third direction (z) which faces the division tracks.

[0024] In a further embodiment of the invention, at least one of the two permanent magnets can be designed as a bar magnet. In the case of a permanent magnet with a rectangular cross-section, the longitudinal edges can define the length X PM , and the secondary edges can define the width Y PM and the height Z PM .

[0025] A permanent magnet is a magnet made of a semi-hard or hard magnetic material, such as an alloy of iron, cobalt, nickel, or certain ferrites. The magnetic field of a permanent magnet is a static magnetic field. A permanent magnet has one or more north and south poles on its surface.

[0026] Analogous to permanent magnets, the sensor fields can also be approximately described as cuboids, with the longitudinal edges defining the length XS and the secondary edges defining the width YS and the height ZS. Here, ZS « XS and ZS « YS .

[0027] In a further embodiment of the invention, the two permanent magnets can be dimensioned in length, width, and height, and alternatively or additionally, the first air gap can be dimensioned in the second direction (y) and alternatively or additionally, the second air gap can be dimensioned in the third direction (z), such that at least in the region of the sensor fields, the magnetic field forms homogeneous regions at least in one plane of the first and second directions (x,y plane). It is advantageous here that the homogeneous regions of the magnetic field can lead to a pre-magnetization of the sensor fields in the second direction, which counteracts the formation of magnetic domains in the metal strips of the sensor fields.

[0028] The geometries of the individual permanent magnets, the choice of the energy product of the individual permanent magnets as well as the first and, additionally or alternatively, the second air gap can be used as control variables for influencing the local position of the homogeneous areas.

[0029] In a further embodiment of the invention, the first permanent magnet can be dimensioned, particularly in the first direction (x) and additionally or alternatively in the second direction (y), such that it extends beyond the dimensions of the first sensor field. Similarly, the second permanent magnet can be dimensioned, particularly in the first direction (x) and in the second direction (y), such that it extends beyond the dimensions of the second sensor field.

[0030] The dimensions of a sensor field refer to those edges that define the length and width of the sensor field. Otherwise, they refer to the edge(s) of the orthogonal projection (in the third direction z) of the sensor field area onto the plane (x,y plane) in which the permanent magnet is located.

[0031] In a further embodiment, the first permanent magnet can be dimensioned such that only its dimension in the second direction (y) is larger than the dimensions of the first sensor field in the second direction (y). Similarly, the second permanent magnet can also be dimensioned such that only its dimension in the second direction (y) is larger than the dimensions of the second sensor field in the second direction (y).

[0032] According to a further embodiment, the two permanent magnets can be geometrically identical, ie the design, the cross-sectional shape and the edge length of the first permanent magnet and the second permanent magnet are the same.

[0033] According to a further embodiment of the invention, the two permanent magnets can have an identical energy product, ie the energy product of the first permanent magnet and the energy product of the second permanent magnet have the same amount.

[0034] The energy product of a permanent magnet is the maximum product of magnetic flux density and magnetic field strength that can be present simultaneously in the material of a permanent magnet.

[0035] In a further embodiment of the invention, the dimension of the first air gap in the second direction (y) is dimensioned such that it corresponds at least to the dimension of the third sensor field in the second direction (y).

[0036] In a further embodiment of the invention, the scale element can have at least one further graduation track which is designed to be incremental. The further graduation track can also be arranged between the first and second graduation tracks, so that the first, second, third and further graduation tracks are arranged parallel and spaced apart in a second direction (y). At least one further sensor field can also be arranged opposite the further graduation track in the third direction (z). The sensor fields in the detection element are designed such that the graduation tracks can be scanned by them. The first permanent magnet is arranged offset from the first graduation track in the third direction (z) such that the first sensor field lies between the first graduation track and the first permanent magnet.Additionally or alternatively, the second permanent magnet is arranged offset from the second graduation track in the third direction (z) such that the second sensor field lies between the first graduation track and the second permanent magnet. The magnetic field between the first and second permanent magnets is designed such that at least the third sensor field and the further sensor field lie in a region of the magnetic field with homogeneous field line components with respect to at least one plane of the first and second directions (x,y planes) and can be penetrated by the formed magnetic field. The first sensor field, the second sensor field, the third sensor field and the further sensor field can lie in one plane (x,y plane). Alternatively, the first and second sensor fields lie in a first plane (x,y plane) and the third and further sensor fields lie in a second plane (x,y plane).The first plane differs from the second plane in terms of its position in the third direction (z).

[0037] The invention is explained in more detail below with regard to further features and advantages based on the description of exemplary embodiments and with reference to the accompanying schematic drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Fig. 1 is a side view of a position measuring device configured as an angle measuring device; Fig. 2 is a sectional view of the position measuring device according to a first embodiment; Fig. 3 is a plan view of a scale element; Figs. 4a, 4b are representations of the magnetization directions of the permanent magnets with schematic identification of the magnetic field; Fig. 5 is a plan view of a position measuring device according to the first embodiment; Fig. 6 is a front view of the detection element according to the first embodiment; Fig. 7a is a perspective view of the first permanent magnet; Fig. 7b is a perspective view of the first sensor field in a simplified representation; Fig. 8 is a plan view of a position measuring device according to a second embodiment; Fig. 9 is a sectional view of a position measuring device according to a third embodiment. DESCRIPTION OF THE EMBODIMENTS

[0039] Some specific embodiments of the present invention will be described in more detail below with reference to the drawings.

[0040] This shows Fig. 1 a position measuring device according to the invention, designed as an angle measuring device, comprising a scale element 1 and a detection element 2. The two main components of the position measuring device (scale element 1 and detection element 2) are arranged at a distance from one another in a third direction z and are, for example, mechanically coupled to two machine elements which can move relative to one another in a rotational manner along a first direction x, wherein their relative or absolute position (angular position or linear position) is detected.

[0041] According to a first embodiment in Fig. 2The position measuring device comprises a scale element 1 with a first graduation track 1.1, a second graduation track 1.2, and a third graduation track 1.3. Furthermore, the position measuring device comprises a detection element 2, which comprises at least one first sensor field 2.1, at least one second sensor field 2.2, and at least one third sensor field 2.3. The sensor fields 2.1, 2.2, 2.3 can be designed as magnetically sensitive structures applied to one and the same flat substrate 4 (for example, a glass substrate). Furthermore, the detection element 2 comprises a first permanent magnet 2.10 and a second permanent magnet 2.20, as well as evaluation electronics (not shown).

[0042] In the presented embodiment, the three sensor fields 2.1, 2.2, 2.3 function according to the magnetoresistive principle, with a layer sensitive to magnetic fields facing the scale element 1. The three sensor fields 2.1, 2.2, 2.3 are arranged offset in the third direction z with respect to the graduation tracks 1.1, 1.2, 1.3, so that a third air gap L 3 is formed. In a linear scale element 1, the sensor fields 2.1, 2.2, 2.3 are advantageously arranged such that the third air gap L 3 is formed across the surface of the magnetically sensitive layer with an approximately constant dimension in the third direction z. In the case of a drum-shaped scale element 1, the dimensions of the third air gap L 3 can vary between the individual sensor surfaces and the graduation tracks below.

[0043] The first permanent magnet 2.10 is offset from the first graduation track 1.1 in the third direction z, so that it is arranged in the region of the first sensor field 2.1 opposite the back of the substrate 4. A second air gap L2 can be formed between the first sensor field 2.1 and the first permanent magnet 2.10. Analogously, the second permanent magnet 2.20 is offset from the second graduation track 1.2 in the third direction z, so that it is arranged opposite the back of the second sensor field 2.2. The second air gap L2 can also be formed between the second sensor field 2.2 and the second permanent magnet 2.20. A first air gap L1 is located in the second direction y between the first permanent magnet 2.10 and the second permanent magnet.

[0044] How Fig. 3As can be seen, the scale element 1 according to a first embodiment of the invention comprises three graduation tracks 1.1, 1.2, 1.3, of which two are absolute and one is incremental. The scale element 1 is advantageously designed such that the third graduation track 1.3 is arranged between the first graduation track 1.1 and the second graduation track. The first and second graduation tracks 1.1, 1.2 of the scale element 1 each have at least one absolute magnetic code graduation, which can be designed, for example, such that it has areas with a magnetic north pole and areas with a magnetic south pole at irregular intervals, which individually or combined form predefined position information, e.g. in the form of a pseudo-random sequence. The third graduation track 1.3 of the scale element 1 has at least one relatively fine incremental magnetic code division, which can be formed, for example, by means of alternating north and south poles at regular intervals from one another.

[0045] The code divisions of the division tracks 1.1, 1.2, 1.3 in Fig. 3 are simplified and therefore only shown schematically.

[0046] The Figures 4a, 4bshow the magnetization directions of the permanent magnets 2.10, 2.20 of the position measuring device according to the invention. The permanent magnets 2.10, 2.20 are arranged such that the magnetization direction of the two permanent magnets is identical and the resulting magnetic field B is formed at least in partial areas with a homogeneous component with respect to at least one plane of the first and second directions (x,y planes) and in the second direction (y direction). This means that either the pole side with north N of the first permanent magnet 2.10 is opposite the pole side with south S of the second permanent magnet 2.20 (see Fig. 4a ) or that the pole side facing south S of the first permanent magnet 2.10 is arranged opposite the pole side facing north N of the second permanent magnet 2.20 (see Fig. 4b ).

[0047] Fig. 5shows the position measuring device according to the invention according to the first exemplary embodiment in a top view. The first permanent magnet 2.10 is arranged centrally in the first direction x and centrally in the second direction y with respect to the first sensor field 2.1 (shown in dashed lines), and the second permanent magnet 2.20 is similarly arranged centrally in the first direction x and centrally in the second direction y with respect to the second sensor field 2.2 (shown in dashed lines).

[0048] The two permanent magnets 2.10, 2.20 are dimensioned such that they protrude over the sensor fields 2.1, 2.2, i.e. in particular the outer dimensions of the permanent magnets 2.10, 2.20 in length X PM and width Y PM are greater than the length XS and width YS of the underlying sensor fields 2.1, 2.2. Alternatively, the two permanent magnets 2.10, 2.20 can be designed such that only one of the dimensions (length X PM , width Y PM ) is greater than the corresponding dimension of the sensor field arranged below (length XS , width YS ). The remaining dimension can be either identical or smaller than that of the sensor field arranged below the case is.

[0049] The two permanent magnets 2.10, 2.20 and the sensor fields 2.1, 2.2, 2.3 arranged underneath are aligned so that their longitudinal edges (length X PM or XS ) run parallel along the first direction x and the secondary edges (height Z PM or ZS ) run parallel to the third direction z.

[0050] The code divisions of the division tracks 1.1, 1.2, 1.3 in Fig. 5 are simplified and therefore only shown schematically.

[0051] As in Fig. 6As shown schematically, a magnetic field B with characteristic field line paths, indicated by magnetic field vectors, forms between the first and second permanent magnets 2.10, 2.20. In particular, above, below, and between the two permanent magnets, the magnetic field forms approximately homogeneous regions in at least one plane of the first and second directions (x,y planes), characterized by magnetic field vectors extending in the second direction y. The sensor fields 2.1, 2.2, 2.3 are advantageously arranged relative to the permanent magnets such that they lie within the effective range of the magnetic field B.

[0052] According to the first embodiment, the first permanent magnet 2.10 is arranged offset in the third direction z relative to the first sensor field 2.1, such that it lies in a region of at least one plane of the first and second directions (x,y planes) of the magnetic field B with an approximately homogeneous field line pattern with a direction vector in the second direction y (y direction). Analogously, the second permanent magnet 2.20 is arranged offset in the third direction z relative to the second sensor field 2.2, such that it also lies in a region of at least one plane of the first and second directions (x,y planes) of the magnetic field B with an approximately homogeneous field line pattern with a direction vector in the second direction y (y direction). The third sensor field 2.3 is arranged such that it lies in a plane with the first and second sensor fields 2.1, 2.2 and is arranged between them, so that it also lies in a region of at least one plane of the first and second directions x, y (x, y planes) of the magnetic field B with an approximately homogeneous field line path with a direction vector in the second direction y (y direction). The geometries of the individual permanent magnets 2.10, 2, 20, the choice of the energy product of the individual permanent magnets 2.10, 2, 20, the first air gap L 1 and, additionally or alternatively, the second air gap L 2 can be used as control variables for influencing the local position of the homogeneous regions.

[0053] How Fig. 7aAs can be seen, the first permanent magnet 2.10 can be shaped as a bar magnet with a rectangular cross-section, wherein the longitudinal edges define the length X PM and the secondary edges the width Y PM and the height Z PM . Analogously, the second permanent magnet 2.20 can be designed identically to the first permanent magnet 2.10, wherein the longitudinal edges also define the length X PM and the secondary edges the width Y PM and the height Z PM of the second permanent magnet 2.20.

[0054] The sensor fields 1.1, 1.2, 1.3 can be used according to the Figure 7b can be approximately described as a cuboid, where the long edges define the length XS and the side edges define the width YS and the height ZS. Here, ZS « XS and ZS « YS .

[0055] Fig. 8shows a second embodiment of the position measuring device according to the invention, which provides at least one further graduation track 1.4 between the first graduation track 1.1 and the second graduation track 1.2, as well as next to the third graduation track 1.3, which is designed incrementally and wherein at least one further sensor field 2.4 is arranged in the third direction z opposite the at least one further graduation track 1.4. The magnetic field B between the first and second permanent magnets 2.10, 2.20 is designed such that both the third sensor field 2.3 and the further sensor field 2.4 lie in a region of at least one plane of the first and second directions x, y (x, y planes) of the magnetic field B with a homogeneous field line course with a directional vector in the second direction y (y direction) and can be penetrated by the formed magnetic field B. The first sensor field 2.1, the second sensor field 2.2, the third sensor field 2.3 and the further sensor field 2.4 lie in one plane (x,y plane).

[0056] The code divisions of the division tracks 1.1, 1.2, 1.3, 1.4 in Fig. 8 are simplified and therefore only shown schematically.

[0057] According to a third embodiment in Fig. 9the sensor fields 2.1, 2.2 can be arranged relative to one another in the third direction z, such that the first sensor field 2.1 is arranged between the first graduation track 1.1 and the first permanent magnet 2.10, and the second sensor field 2.2 is arranged between the second graduation track 1.2 and the second permanent magnet 2.20, wherein the first and second sensor fields 2.1, 2.2 lie in one plane (x,y plane). The sensor fields 2.1, 2.2, 2.3 are designed as magnet-sensitive structures, wherein a separate flat substrate 4 is used for each sensor field 2.1, 2.2, 2.3. Alternatively, the same substrate 4 can be provided for the first and second sensor fields 2.1, 2.2, which then extends flatly in one plane (x,y plane) (not shown).

[0058] A third air gap L 3 is formed between the first graduation track 1.1 and the first sensor field 2.1 and additionally or alternatively between the second graduation track 1.2 and the second sensor field 2.2. The third sensor field 2.3 is arranged offset in the third direction z to the third graduation track 1.3, but is not in the same plane (x,y plane) as the first and second sensor fields 2.1, 2.2. The third air gap L' 3 is formed between the third graduation track 1.3 and the third sensor field 2.3. The third sensor field 2.3 is advantageously arranged such that it lies in a homogeneous region of at least one plane of the first and second directions x, y (x,y planes) of the magnetic field B between the first and second permanent magnets 2.10, 2.20 with a direction vector in the second direction y (y direction).

Claims

1. Position measuring device comprising a detection element (2) and a scale element (1) which is movable relative to the detection element (2) along a first direction (x), wherein the scale element (1) has a first graduation track (1.1) and a second graduation track (12), both of which are designed for absolute values, and a third graduation track (1.3), which is designed for incremental values, wherein the three graduation tracks (1.1; 1.2; 1.3) are arranged parallel to each other and spaced apart from each other in a second direction (y), wherein the second direction (y) is oriented orthogonally to the first direction (x), and the detection element (2) comprises a first sensor array (2.1) which is arranged opposite the first graduation track (1.1) in a third direction (z), comprises a second sensor array (2.2) which is arranged opposite the second graduation track (1.2) in the third direction (z), and comprises a third sensor array (2.3) which is arranged opposite the third graduation track (1.3) in the third direction (z), wherein the third direction (z) is oriented orthogonally to the second direction (y) and orthogonally to the first direction (x), and the magnet-sensitive sensor arrays (2.1; 2.2; 2.3) are configured such that the magnetic graduation tracks (1.1; 1.2; 1.3) can be scanned by these magnet-sensitive sensor arrays, wherein the detection element (2) additionally comprises: a first permanent magnet (2.10), which is arranged offset in the third direction (z) with respect to the first sensor array (2.1), and a second permanent magnet (2.20), which is arranged offset in the third direction (z) with respect to the second sensor array (2.2), wherein a first air gap (L1) is located between the first and the second permanent magnet in the second direction (y).

2. Position measuring device according to Claim 1, wherein the third graduation track (1.3) is arranged between the first graduation track (1.1) and the second graduation track (1.2).

3. Position measuring device according to either of the preceding claims, wherein the magnetization direction of the two permanent magnets (2.10; 2.20) is identical.

4. Position measuring device according to any of the preceding claims, wherein the longitudinal edges (XS) of the sensor arrays (1.1; 1.2; 1.3) have a directional component parallel to the first direction (x) and / or the pole orientation of the permanent magnets (2.10; 2.20) has a directional component perpendicular to the first direction (x).

5. Position measuring device according to any of the preceding claims, wherein the first permanent magnet (2.10) is arranged offset in the third direction (z) with respect to the first graduation track (1.1) in such a way that the first sensor array (2.1) lies between the first graduation track (1.1) and the first permanent magnet (2.20), and / or the second permanent magnet (2.20) is arranged offset in the third direction (z) with respect to the second graduation track (1.2) in such a way that the second sensor array (2.2) lies between the second graduation track (1.2) and the second permanent magnet (2.20).

6. Position measuring device according to any of the preceding claims, wherein a second air gap (L2) is formed between the first permanent magnet (2.10) and the first sensor array (2.1) in the third direction (z), and / or a second air gap (L2) is formed between the second permanent magnet (2.20) and the second sensor array (2.2) in the third direction (z).

7. Position measuring device according to any of the preceding claims, wherein the first permanent magnet (2.10) is arranged on the rear side of the first sensor array (2.1), and / or the second permanent magnet (2.20) is arranged on the rear side of the second sensor array (2.2).

8. Position measuring device according to any of the preceding claims, wherein at least one of the two permanent magnets (2.10; 2.20) is in the form of a bar magnet.

9. Position measuring device according to any of the preceding claims, wherein the two permanent magnets (2.10; 2.20) are dimensioned in length (XPM), width (YPM) and height (ZPM) in such a way and / or the first air gap (L1) is dimensioned in the second direction (y) in such a way and / or the second air gap (L2) is dimensioned in the third direction (z) in such a way that the magnetic field (B) is homogeneous at least according to the second direction (y direction) at least in the region of the sensor arrays (2.1; 2.2; 2.3).

10. Position measuring device according to any of the preceding claims, wherein the first permanent magnet (2.10) is dimensioned such that it exceeds the dimensions of the first sensor array (1.1), and / or the second permanent magnet (2.20) is dimensioned such that it exceeds the dimensions of the second sensor array (2.20).

11. Position measuring device according to Claim 10, wherein the first permanent magnet (2.10) is dimensioned such that only the dimension of the first permanent magnet in the second direction (y) is greater than the dimension of the first sensor array (1.1) in the second direction (y), and / or the second permanent magnet (2.20) is dimensioned such that only the dimension of the second permanent magnet in the second direction (y) is greater than the dimension of the second sensor array (1.2) in the second direction (y).

12. Position measuring device according to any of the preceding claims, wherein the two permanent magnets (2.10; 2.20) are geometrically identical.

13. Position measuring device according to any of the preceding claims, wherein the two permanent magnets (2.10; 2.20) have an identical energy product.

14. Position measuring device according to any of the preceding claims, wherein the dimension of the first air gap (L1) in the second direction (y) corresponds at least to the dimension of the third sensor array (2.3) in the second direction (y).

15. Position measuring device according to any of the preceding claims, wherein the scale element (1) has at least one further graduation track (1.4), which is designed for incremental values and is arranged between the first graduation track (1.1) and the second graduation track (1.2), wherein at least one further sensor array (2.4) is arranged opposite the at least one further graduation track (1.4) in the third direction (z).