WO2009083043A2

WO2009083043A2 - Method and apparatus for generating a material measure for position measuring systems, and material measure

Info

Publication number: WO2009083043A2
Application number: PCT/EP2008/007233
Authority: WO
Inventors: Michael Schneider
Original assignee: Baumer Holding Ag
Priority date: 2007-12-21
Filing date: 2008-09-04
Publication date: 2009-07-09
Also published as: WO2009083043A3; CH700456B1; DE102007063006A1

Abstract

The invention relates to a method and an apparatus for generating material measures (1) as well as a material measure. In order to precisely design the boundaries (6) between the poles (N, S) that are magnetized into the material measure (1) and obtain symmetrical magnetization on both sides of the pole boundaries (6), at least some sections of at least one track of the material measure are magnetized by means of a coarse magnetizing field (13) that has a first field direction (FG) oriented relative to the surface (8) of the material measure, and poles (N, S) having a different polarity are alternately generated. In the area between the poles generated by the coarse magnetizing field (13), at least some sections of the track are magnetized by means of a fine magnetizing field (15) that has a second field direction (FF) extending substantially perpendicular to the field direction (FG) of the coarse magnetizing field (13). In the obtained material measure, the track is magnetically less saturated at the pole boundary (6) than in the adjoining sections of the pole boundary (6) in the direction of the track (SR).

Description

Method and device for producing a material measure for position measuring systems and material measure

The invention relates to a method for producing a material measure for position measuring systems in which at least one track of the material measure is magnetized at least in sections with a coarse magnetization field having a first field direction oriented relative to the surface of the material measure and poles of different polarity are generated alternately. The invention further relates to a magnetizing device for magnetizing measuring graduations for position measuring devices, having a receptacle for at least one measuring graduation and having at least one coarse magnetizing head, by which a coarse magnetizing field acting on the material measure can be generated with a first field direction during operation.

Finally, the invention also relates to a material measure produced by this method and apparatus. In particular, the material measure may have at least one track of tracked, magnetically saturated and alternately polarized poles.

Such magnetic measuring graduations are used in translational or rotary position measuring systems for determining an absolute or relative position, speed or acceleration. The arrangement of the poles along the track takes place according to a predetermined scheme, so that the pole sequence is a representative measure of the change in position of a magnetic sensor moving along the track relative to the material measure.

The more accurately the sequence of poles in the lane corresponds to the predetermined pattern, that is to say its setpoint position, the more accurate the position measuring system operates. As the demands on the accuracy of the position measuring systems increasingly increase, in the prior art, some documents deal with ways to produce material scales with a precise sequence of poles.

JP-A-09 055 317, for example, describes a method and a system for magnetizing a material measure for rotary position measuring systems, in which a sensor detects the actual magnetization of the material measure. The detected magnetization is compared with a signal of an encoder, so that it can be determined whether the actual position of the poles corresponds to their desired position. In the event of a deviation, a re-magnetization depending on the detected error with the same magnetization head as performed in the original magnetization.

A similar process is described in DE-A-10 2005 049 559. There, too, a magnetizable layer of the material measure is first coded and then the realized accuracy of this coding is checked. Subsequently, the deviation of the actual positions of the pole boundaries at which adjacent poles of opposite polarity abut each other and the field strength of the magnetized magnetic field in the track direction has a zero crossing is determined from their target positions. Depending on this deviation, a correction value is calculated and a further coding is carried out as a function of this correction value. This procedure can be carried out until the deviations of the actual position or the size of the correction values fall below predetermined limits.

EP-A-1 006 342 shows a marking method of measuring tracks in which a writing head is guided over the carrier of the measuring track in a marking step. The write head applies magnetic north and south poles at predetermined positions of the carrier. To determine the actual positions of the markings, a read head is provided in addition to the write head. The actual positions of the markings are measured against a reference point and then compared with the nominal positions. In the event of deviations of the actual positions from the nominal positions, markings corrected for the same track are applied whose positions are changed by values which depend on the deviation. The correction of the magnetized track takes place in the form of a renewed correction run of the write head, so that the magnetizations are superimposed.

In DE-A-102 17 983 it is described that the direction of the intrinsic magnetization can be set in one or more layer components by heating the subareas to be magnetized and applying a magnetic field to them.

Magnetizing heads with which material measures are magnetized are described, for example, in DE-A-44 42 682, WO-A-00/54 293 and US-A-2001/0030533.

With regard to the configuration of the tracks and the sequence of poles in position measuring systems, reference is made to DE-A-42 08 918 and the prior art mentioned therein. The accuracy of a material measure is determined not only by the exact position of the pole boundaries, ie by the exact position of the transition between the alternating sections of opposite polarity. It is also essential that the transition between these sections is precisely defined and that the boundary between the sections is sharp. The smaller the extent of this transition region, the more reliably the position of the pole boundary can be determined. In particular, the need for expensive, because very fine-working sensor heads in the position measuring devices must be omitted.

In the previous systems, it is still problematic that the extent of the transition regions containing the pole boundaries is large, which makes exact determination of the position of the pole boundary in the transition region difficult and leads to measurement inaccuracies. In addition, in the case of the known production methods and devices, the course of the magnetic field magnetized into the material measure along the track varies greatly in the transition region. This leads in position measuring systems, in which a sensor often detects several poles of a track at once, to a signal quality changing along the track and ultimately also to measurement errors.

The invention therefore has as its object to improve the known methods and apparatus for the production of magnetic measuring standards so that the expansion of the transition region between adjacent poles is reduced and the magnetization of the transition region along the track is made uniform.

According to the invention, this object is achieved for the aforementioned method in that the track in the region between the poles generated by the coarse magnetizing field is at least partially magnetized with a fine magnetizing field with a second field direction substantially perpendicular to the field direction of the coarse magnetizing field.

For the aforementioned magnetization device, this object is achieved according to the invention in that the successive poles of a track in the track direction are each separated by a magnetically non-saturated transition region.

According to the invention, the material measure produced by this method or apparatus is characterized in that the magnetic saturation of the track at the pole boundary is reduced compared with the sections adjacent in the track direction. Surprisingly, can be produced by this method or this device Maßverkörperungen in which the pole boundaries are defined more clearly than in the previous method. The orientation of the fine magnetization field transversely to the coarse magnetization field allows the transition regions to be magnetized more accurately and uniformly than in the conventional methods. In particular, it is thus possible to adapt the direction of the fine magnetization effect to the measuring direction of the sensor in the position-measuring device and to further adapt the magnetic field of the finished material measure to the measuring method or the field component measured by the sensor. This results in an increased accuracy in the reading of the material measure in position measuring systems.

The method and the device for producing the material measure as well as the material measure itself can be further improved by the following independent developments.

Thus, in a first development, for example, the coarse magnetization field with a higher field strength act on the track than the fine magnetization field. As a result, large-magnetization poles can also be used to rapidly magnetize poles of great extent, while the effect of the fine magnetization field preferably remains local.

Further, the speed of the manufacturing process can be increased without sacrificing accuracy if the portions magnetized by the fine magnetizing field have a smaller extension in the tracking direction than the portions magnetized by the rough magnetizing field. In particular, the fine magnetization field can be magnetized only in the transition region between the poles which includes the pole boundaries.

On the one hand, the fine magnetization field can be controlled on the basis of previously determined empirical data in which the average errors of an ensemble of results of the coarse magnetizations are taken into account. In this method, a very high accuracy can already be achieved without much effort, since the systematic errors due to the magnetization device, the geometry of the material measure and the material of the track to be magnetized are taken into account.

However, the fine magnetization can also be carried out after a comparison of the actual position of at least a part of the pole boundaries generated in the coarse magnetization step with the desired position of these pole boundaries, wherein after the action of the fine magnetization tion field, the deviation of the actual position of the finely magnetized pole boundaries is reduced from the desired position. This method with a control measurement of the result of the respective coarse magnetization is time-consuming, but allows highest accuracies.

In order to detect the actual position of the poles generated by the coarse magnetizing field, the magnetizing device may comprise a sensor and a control device. By the control device, the actual position of the pole boundaries detected by the sensor can be compared with its desired position and the deviation of the actual position from the desired position can be determined. By the control device, the polarity of the fine magnetization field in dependence on the actual position or its deviation from the desired position can be switched.

The problem with the previous methods and devices for the magnetization of material measures that although the magnetized track is adapted to an ideal pole sequence with exact positioning of the poles, this ideal pole sequence does not lead to ideal, harmonic-free measurement signals in the sensors actually used. These harmonics ultimately affect the positioning accuracy. With the invention, it is possible to adapt the course of the magnetic field, in particular in the transition region, to a sensor such that it delivers a signal with improved signal quality, as explained in more detail below.

In one embodiment, the coarse magnetizing field and the fine magnetizing field are preferably matched to one another such that a substantially harmonic-free measuring signal is produced at the sensor in the position-measuring device. The tuning of the magnetized magnetic field takes place in such a way that a harmonic-free, sinusoidal measurement signal is generated by a sensor head, which is installed in the position measuring device at a predetermined distance from the spurt. This can be influenced according to the invention by an adaptation of the magnetization curve in the transition region.

In particular, the coarse magnetizing field and the fine magnetizing field can be controlled on the basis of a computer model which calculates the measuring behavior of the sensor and the measuring signal supplied by the sensor of the position-measuring device. In this case, in one variant, only the fine magnetization field can be calculated and controlled as a function of the coarse magnetization field always generated in the same way. In order to be able to adapt the fine magnetization field as exactly as possible to the errors of the pole sequence generated by the coarse magnetization field, it is advantageous if, in the control measurement, the components of the magnetic field impressed by the coarse magnetizing field in the direction of comparison of the actual position with the desired position of the fine magnetization field. Consequently, in this embodiment, the measurement already detects that component of the magnetic field in which the fine magnetization field acts on the material measure.

In order to keep the hysteresis and memory effects of the magnetic field impressed by the coarse magnetization field as small as possible, in a further advantageous embodiment of the method in the coarse magnetization step gaps between the poles can not be magnetized or demagnetized. In this case, therefore, no pole boundaries between the poles are generated by the coarse magnetization field, since the poles of a track are magnetized apart in track direction from one another.

Since, with regard to the fine magnetization field in the case of the coarse magnetization, the accuracy of the pole boundaries and the extent of the transition region are limited, a large number of poles can be generated simultaneously in order to accelerate the method in the coarse magnetization step.

In this case, the magnetization device preferably has a multiplicity of coarse magnetization heads whose arrangement in the tracking direction corresponds to the arrangement of the poles to be magnetized. The coarse magnetization heads may have permanent magnets.

The result of the magnetization by the fine magnetization field can be improved if the coarse magnetizing field is generated with a field direction perpendicular to the surface of the material measure. It follows according to the invention that the fine magnetization field is tangential to the surface of the material measure, but in particular aligned in the track direction runs. The at least one fine magnetization head of the magnetization device can in this case be provided with two pole regions of different, preferably reversible, polarity spaced apart in the track direction.

In particular, if the fine magnetization field has a field direction parallel to the track direction, the extent of the transition region can be reduced and a uniform magnetization of the transition regions can be achieved along the track. In this embodiment, the course of the magnetization in the transition region from the course of the Fine Magnetisierungsfeldes in Feinmagnetisierungskopf determined and remains virtually unchanged along the track. The transition region has, in particular in this embodiment, a high symmetry with respect to the pole boundary, which leads to a particularly high signal quality during scanning in the position measuring system.

The magnetization device may also have a plurality of fine magnetization heads whose position is assigned to the positions of the transition regions between the poles to be magnetized by the coarse magnetization heads or the pole boundaries. Although the fine magnetization step is accelerated by this measure in order to uniformly magnetize over the transition regions, the fine magnetization heads must be carefully calibrated.

The coarse magnetization heads and / or the fine magnetization heads may be arranged in the magnetization device such that the receptacle for the at least one measuring scale and the fine or coarse magnetizing heads are movable relative to one another in the track direction.

The magnetization device can also have at least one magnetization head in which the coarse magnetization head and the fine magnetization head are integrated and which can simultaneously or successively generate the fine magnetization field and the coarse magnetization field.

Furthermore, in the transition region in which the fine magnetization step has been carried out and the fine magnetization field has acted on the track, the material measure may have at least one subregion with sections which have a residual polarity opposing the polarity of the environment. Furthermore, in the transition region, at least one subregion with non-magnetized sections or with sections which have a random distribution of the magnetic field may be present if a non-magnetized or demagnetized gap has been created or left from the coarse magnetization field between the poles. This refinement has the advantage that the fine magnetizing field directly determines the course of the magnetic field magnetized in the transition region and does not interact with an already existing, uneven coarse magnetizing field.

Finally, a material measure is claimed, which is produced by the method in one of the embodiments described above. The claimed magnetizing device is basically suitable for carrying out such a method. The invention is explained in more detail below by way of example with reference to exemplary embodiments with reference to the drawings. The combination of features in the examples given below is for illustrative purposes only and may be varied in accordance with the above embodiments and the advantages associated with these embodiments. For elements of the same function and / or same structure, the same reference numerals will be used in the following for the sake of clarity.

Show it:

Fig. 1 is a schematic plan view of a rotary measuring scale;

FIG. 2 shows a sectional view along the line M-II of the rotary measuring graduation of FIG. 1; FIG.

3 is a schematic plan view of a translational material measure;

4 shows a schematic sectional view along the line IV-IV of the translational measuring graduation of FIG. 3;

5 is a schematic representation of the course of the magnetization intensity M in the track direction SR of a material measure;

FIG. 6 shows a schematic representation of the sequence of the method according to the invention for the magnetization of material measures; FIG.

7 is a schematic representation of a first embodiment of a magnetization device according to the invention;

8 shows the profile of the magnetization intensity M in the track direction SR according to a first embodiment of the method;

Fig. 9, the magnetization intensity M in the track direction SR according to another

Embodiment of the method;

10 shows a schematic side view of a further embodiment of a magnetization device according to the invention;

11 shows a schematic side view of a further embodiment of the magnetization device according to the invention; Fig. 12 is a schematic view along the line XII-XII of Fig. 11;

Fig. 13 is a schematic representation of the course of the degree of saturation R in

Track direction SR in a material measure according to the invention;

14 is a schematic sectional view in the region of the detail XIV of FIG. 1 or FIG. 3.

First, the structure of a material measure 1 will be explained with reference to the schematic representations of FIGS. 1 to 4.

The measuring graduation of FIGS. 1 and 2 is used to detect rotary rotational movements and is constructed substantially annular. The material measure 1 is alternately provided with magnetic markings N, S, which form magnetic north poles N and magnetic south poles S, for example. The markings N, S follow one another in a track direction SR and thus form a track 2. The track 2 extends annularly and preferably coaxially to the annular dimensional standard 1 about a pivot O of the rotational movement to be monitored.

The track 2 can be scanned by a sensor, not shown in FIG. 1 for the sake of simplicity, of a position measuring device which moves relative to the material measure. The sequence of markings N, S detected by the sensor makes it possible to draw conclusions about the relative position of the material measure and the sensor, the relative speed of the material measure and sensor, and / or the relative acceleration of the material measure and sensor. In the case of the rotary measuring graduation of FIGS. 1 and 2, the variables detected by the position measuring device are, for example, the angular position, speed and acceleration.

The material measure may in addition to the track 2 also have more tracks 3, which run concentrically to the track 2 and is also provided with marks N, S. These tracks 3 can each other sensors (not shown) may be assigned in the position measuring device.

The extent of the markings N, S in the track direction SR depends on the specific application. For incremental encoders, in which the change of the angular position with respect to the previous angular position is detected in incremental steps, the extents of the markings N, S in the track direction SR can be equal in each case, so that they are equiangular are distributed over the circumference. The extent of the poles N, S determines the resolution of the material measure and the accuracy with which the rotational movement can be resolved.

In the case of absolute encoders in which the angular position is conventionally encoded in a plurality of tracks 2, 3 as an absolute position value relative to a starting position, the dimensions of the marks N, S in the track direction SR can be of different sizes.

2 shows schematically the construction of the material measure of FIG. 1 in a sectional view along the line M-II. Accordingly, the material measure may consist of a mechanically stable carrier 4, which preferably has a low thermal expansion and forms the magnetic yoke.

On the end face and / or the outer and / or inner circumferential surface of the carrier 4, a layer 5 of hard magnetic material is applied. The layer 5 can be produced by a coating process on the carrier 4, for example by applying a liquid mass on the one end face of the carrier 4. Alternatively, finished layers 5 in the form of rings, ribbons or foils can be attached to the support 4. The layer 5 can also be an integral part of the carrier 4.

The translational measuring graduations 1, one of which is shown schematically in FIG. 3 in a plan view and in FIG. 4 in a sectional view along the line IV-IV of FIG. 3, have in principle the same structure as the rotary measuring graduation 1 of FIG 1 and 2. They differed only in that the track direction SR is linear and the measuring scale 1 is designed as a straight-line scale. The relative movement between a sensor of the positioning device and the material measure 1 is in this case a rectilinear movement.

The sensor K moves at a predetermined distance D from the surface. At this distance, the sensor K detects the magnetic field I generated by the material measure 1 and forms a signal Z. The invention strives to improve the quality and accuracy of the signal Z.

Of course, with appropriate guidance of the track 2, 3 scanning sensor, the track 2, 3 have an arbitrarily curved course.

FIG. 5 schematically shows the ideal profile of the magnetization intensity M of a track 2, 3 in the track direction SR. In track direction, the sections N, S alternate in different polarity, ie north and south poles. Ideally, the magnetic material is the layer 5 to the pole boundary 6, the zero crossing between the sections of different polarity, saturated and the transitions between north and south pole take place abruptly. The sensor moving along the track detects, as a measured value, primarily the switching from one polarity to the other polarity than the signal representative of the movement to be detected. Thus, the pole boundaries 6 are determining for the motion monitoring.

In practice, the pole boundaries 6 are not as sharp as shown in Fig. 5, but have a measurable extent in the track direction SR. In addition, the pole boundaries 6 smear to a transition region U, shown schematically in FIG. Thus, the position of the pole boundary 6 can no longer be determined exactly and the accuracy of the position determination is reduced.

The object of the invention is to provide dimensional scales 1 with sharply defined and exactly positioned pole boundaries 6, in which the transitional areas along the track have a uniform and symmetrical magnetization profile and the position of the pole boundaries can be determined more accurately and easily.

This is achieved according to the invention by the method steps shown schematically in FIG.

According to the invention, in a first method step, the coarse magnetization step 7, the basic pattern of the pole sequence N, S is magnetized into the material measure 1. In this case, a magnetizing coarse magnetizing field, whose field direction has a first orientation relative to the surface 8 (FIGS. 2, 4) of the material measure 1, acts on the material measure 1.

Subsequently, a fine magnetization step 9 is performed in order to purposefully reduce the extent of the transition regions generated in the coarse magnetization step 7 and the degree of saturation in the transition regions. As a result, the magnetic influence of the saturated regions of the poles N, S on the pole boundary 6 is reduced and the course of the pole boundary 6 can be detected more easily by measurement.

In the fine magnetization step 9, a fine magnetization field acts on the material measure 1, the orientation of which runs perpendicular to the orientation of the coarse magnetization field. Preferably, the field direction of the coarse magnetization field is perpendicular to the surface 8. The field direction of the fine magnetization field is then tangent to the Surface 8, preferably in the track direction SR. In particular, with an orientation of the fine magnetization field in the track direction, it is possible to produce a uniform and symmetrical course of the pole boundaries over the track since the field magnetized in the track direction substantially follows the course of the fine magnetization field.

The coarse magnetization step 7 and the fine magnetization step 9 can also be carried out simultaneously in which the fine and the coarse magnetization field are simultaneously generated by one or more magnetic heads.

As indicated by the dot-dash lines in FIG. 6, a step 10 may be interposed between the coarse magnetization step 7 and the fine magnetization step 9 in the form of a control measurement. In step 10, the actual positions of the pole boundaries 6 generated in the coarse magnetization step 7 in the track 2, 3 are measured and compared with the predetermined desired positions of the pole boundaries 6. The fine magnetization step 9 is then carried out as a function of this comparison so that after the fine magnetization step 9, the deviation of the actual positions from the desired positions of the pole boundaries 6 is reduced. For this purpose, in step 10, a sensor is guided along the coarse-magnetized track 2, 3 and the position of the sensor is monitored with a reference scale. The sensor preferably measures the components of the magnetic field magnetized in the material measure 1 in the coarse magnetization step in the direction of the fine magnetization field still to be applied, preferably thus tangentially in the track direction.

With the aid of step 10, the accuracy of the material measure 1 can be increased. However, the effort is not inconsiderable. A sufficient for many applications, compared to the conventional measuring standards significantly improved accuracy can be achieved if the Feinmagnetisierungsschritt 9 the Feinmagnetisierungsfeld without a control measurement after each coarse magnetization is always applied the same and positioning the Feinmagnetisierungsfeldes from an empirical or analytical examination of the systematic error sources of Groblmagne- tisierungsschrittes and Feinmagnetisierungsschritt.es results. Thus, the largest systematic errors in the magnetization of the material measure 1 can already be eliminated, without an expensive measurement method and complex control and traversing devices for setting the fine magnetization field are necessary.

Alternatively, the magnetic field resulting from fine and coarse magnetization can also be calculated at the location of a sensor of the position-measuring device and the coarse and fine magnetization field, in particular only the fine magnetization field can be adjusted so that a desired magnetic field arises at the location of the sensor. In this step, the measurement behavior of the sensor, that is, the measuring field generated by the sensor as a function of the magnetic field can also be calculated. In this case, fine and coarse magnetizations or, if the coarse magnetization remains the same, only the fine magnetization is controlled such that the sensor delivers a desired, harmonic-free, and preferably sinusoidal measurement signal. This procedure leads to a particularly high signal quality and measurement accuracy.

Alternatively, a measurement of the entire track 2, 3 does not have to be performed in step 10, but a predetermined number of empirically previously determined reference points can be measured whose errors are representative of predetermined error categories. In this case, the fine magnetization step 9 is performed depending on the detected error category.

FIG. 7 shows a first embodiment of a magnetization device 11. The magnetization device 11 has at least one coarse magnetization head 12, with which the coarse magnetization field 13 can be generated in operation with a field direction F _G , at least one fine magnetization head 14, with which the fine magnetization field 15 is operated with a field direction F perpendicular to the field direction F _{G of} the coarse magnetization field 13 _F can be generated, and optionally at least one sensor 16, with which the position of the pole boundaries 6 and the course of the magnetization M in the transition region U between the pole sequence N, S, see. Fig. 5, can be detected. In dashed lines, another, optional coarse magnetization head 17 is indicated in FIG. Of course, at least one further fine magnetization head 14 (not shown for simplicity) may also be provided. The coarse magnetization head 12 and the fine magnetization head 14 can also be structurally integrated.

The magnetization device 11 may further include a driver 18 and a sensor 19. The drive 18 generates a relative movement between the at least one coarse magnetization head 12 and / or the fine magnetization head 14 on one side and the material measure 1 on the other side. The sensor 19 serves as a reference scale and determines with high precision the relative position of the material measure 1 and of the at least one coarse magnetization head 12 or fine magnetization head 14. The material measure 1 is held in a receptacle H. Finally, the magnetization device 11 may have a control device 20, which is signal-transmitting connected to the at least one coarse magnetization head 12, the at least one fine magnetization head 14, the at least one sensor 16, the drive 18 and the sensor 19.

The control device 20, the signals from the sensor 16 and the sensor 19 are supplied. The control device 20 can also have a memory 21 in which representative values for the desired positions of the pole boundaries 6 are stored. The control device 20 controls the drive 18 and the fine magnetization head 14 as a function of the actual position of the pole boundaries 6 detected by the sensor 16 in the fine magnetization step 14. In addition, the control device 20 controls the actuation of the coarse magnetization head 12 and the drive 18 in the coarse magnetization step 7 as a function of the Sensor 19 received signals.

FIGS. 8 and 9 show two different embodiments of an idealized pole sequence after the coarse magnetization step 7 in the tracking direction SR along a track 2, 3.

According to the embodiment of FIG. 8, regions between the poles N, S remain unmagnetized by the coarse magnetizing field 13. These areas can also be demagnetized in the coarse magnetization step. The poles are thus separated by gaps 22 having a predetermined extent in track direction SR. The transition region U, in which the fine magnetization step 9 is carried out with the aid of the fine magnetization field 15, accordingly contains the gap 22, which takes the place of the pole boundaries 6. In this embodiment, the pole boundaries 6 are magnetized only in the fine magnetization step 9. Since the fine magnetizing field 15 in this embodiment does not have to compensate for an already magnetized coarse magnetizing field 13, the accuracy of the fine magnetization of the transitional region U is markedly increased.

In the embodiment of FIG. 9, the inverted polarized portions N, S generated by the coarse magnetizing field 13 directly adjoin each other to form the pole boundaries 6. The transition region U in which the fine magnetization step 9 is carried out contains the pole boundaries 6. In addition to the sharp definition of the pole boundary 6, in the fine magnetization step its actual position I is adapted to the predetermined desired positions P in the track direction, as indicated by the arrows 23 , As shown in FIGS. 8 and 9, in the track direction SR, the extension W _{G of} the poles N, S generated by the coarse magnetizing field 13 is larger than the extent W _F of the regions magnetized in the fine magnetizing field 15.

Another embodiment of the magnetization device 11 is shown in FIG. This embodiment has a plurality of coarse magnetization heads 12 stationarily disposed at the positions corresponding to the positions of the reverse polarized portions N, S in the track 2. As shown in FIG. The embodiment of FIG. 10 has the advantage that all the poles N, S are generated simultaneously during the coarse magnetization step 7. The coarse magnetization heads 12 are thus arranged along the track 2 in likewise alternating polarity. Preferably, permanent magnets can be used as coarse magnetization heads 12.

The coarse magnetization heads 12 can, if the material measure 1 has only a single track 2, also extend in the manner of a spider in the circumferential direction about the outer circumference of the material measure 1. Of course, in a linear measuring scale, the coarse magnetizing heads 12 are arranged in series next to each other along the track.

A corresponding variant of the magnetization device 11 is shown in FIGS. 11 and 12.

In the schematic side view of FIG. 11 of the magnetization device 11 it is shown that a plurality of dimensional standards 1 are mounted side by side on a mandrel 24 as a receptacle H of the measuring graduations 1 in the axial direction A. Groove magnetization heads 12, in particular permanent magnets, which are arranged next to one another in the circumferential direction, surround a passage opening 25, whose inside width is only slightly larger than the outside diameter of the measuring graduations 1. The mandrel 24 with the dimensional standards 1 is pulled through the opening 25 in the axial direction A, see FIG that in one step, the entire track 2 is roughly magnetized.

In the fine magnetization step 9, the at least one fine magnetization head 14 and the material measure 1 are moved relative to one another, so that, viewed from the track 2, the fine magnetization head 14 moves over the track 2 in the tracking direction SR. The control device 20 actuates the fine magnetization head 14 as a function of the measured deviation of the actual position I of the pole boundaries 6 from their desired position P (FIG. 9). The polarity of the fine magnetization field 15 is thereby determined by the control unit. 20 switched that the polarity of the Feinmagnetisierungsfeldes coincides with the polarity of the opposite pole of the track. Consequently, in the case of the fine magnetization head 14 with a field direction F _F pointing in the track direction SR, the sections of the same polarity of the fine magnetization head 14 and the track 2 are superimposed. The gap of the fine magnetization head, in which the fine magnetization field 15 is formed, approximately corresponds in position and extent to the transition region after the fine-magnetization step 9.

The control device 20 turns off the magnetic field of the fine magnetization head 14 when the gap of the fine magnetization head has reached the target position P of the pole boundary 6. After the fine magnetization step, a course of the magnetic saturation R of the track 2 in the track direction SR, as shown schematically in FIG. 13 and explained below, is thus obtained. The magnetized magnetic field has a high symmetry with respect to the pole boundary. In particular, when always the same fine magnetization head is used, the transition regions have only a few deviations from one another.

In the region of the pole marks N, S, as produced by the coarse magnetization step 7, the saturation limit G in the magnetic material of the material measure 1 is reached. In the transition region U, in which the pole boundary 6 is generated, initially the saturation R decreases in the direction of the pole boundary 6. Saturated poles N, S are thus present on both sides of the transitional region U and the pole boundary 6 is sharply defined. The sharpness of the transition between the alternating polarities depends on the size of the gap in which the fine magnetization field 15 forms. The smaller this gap, the sharper the pole boundary can be magnetized.

If the cross section of the material measure 1 is considered more precisely in a section in the track direction SR, the image shown schematically in FIG. 14 results. FIG. 14 shows the detail XIV of a rotary measuring graduation (FIG. 1) or translational material measure (FIG. 3) in the region of a pole boundary 6 which was moved closer to the nominal position P from its original position 6 'in the course of the fine magnetization step 9 ,

In the region of the saturated poles N, S, outside the transition region U, there are almost no subsections which have a polarization reversed to the pole.

If the coarse magnetization was carried out in the variant illustrated in FIG. 9, the region between the pole boundary 6 'from the coarse magnetization step 7 and the pole magnetization was border 6 after the Feinmagnetisierungsschritt 9 previously almost uniformly reversed polarity. Thus, in the transition region U due to the non-linear properties in the polarity reversal of the material of the material measure 1 are still partial areas which uniformly have the original polarity as residual polarity, which is inversely directed to the vast majority of their environment.

In the case of the variant of the coarse magnetization step 7 of FIG. 8, these subregions 26 have pronounced anisotropy since they were not previously polarized.

Claims

claims

1. A method for producing a material measure (1) for position measuring systems, wherein at least one track (2.3) of the material measure at least partially with a coarse magnetizing field (13) with a first relative to the surface (8) of the measuring graduation oriented field direction (F _G ) is magnetized and alternately poles (N, S) of different polarity are generated, characterized in that the track (2,3) in the region (U) between the Grobmagnetisierungsfeld (13) generated poles (N, S) at least partially with a fine magnetization - Field (15) with a second, the field direction (F _G ) of the coarse magnetizing field (13) substantially perpendicular field directions (F _F ) is magnetized.

2. The method according to claim 1, characterized in that the coarse magnetizing field (15) with a higher field strength on the track (2,3) acts as the fine magnetization field (15).

3. The method according to claim 1 or 2, characterized in that the fine magnetization of the field (15) magnetized portions of the track (2,3) have a smaller extension (W _F , W _G ), as in the coarse magnetization step (7) magnetized sections.

4. The method according to any one of claims 1 to 3, characterized in that the fine magnetization field (15) and the coarse magnetizing field (13) are calculated and generated in dependence on a magnetic field generated at the location of a sensor of the position measuring device of the material measure (1).

5. The method according to claim 4, characterized in that the measurement behavior of the sensor of the position measuring device is taken into account.

6. The method according to any one of claims 1 to 5, characterized in that in the coarse magnetization step (7) between the poles (N, S) lying gaps (22) are not magnetized or demagnetized.

7. The method according to any one of claims 1 to 6, characterized in that in the coarse magnetization step (7) a plurality of poles (N, S) are generated simultaneously.

8. The method according to any one of claims 1 to 7, characterized in that the coarse magnetizing field (13) with a field direction (F _G ) perpendicular to the surface (8) of the material measure (1) is generated.

9. Measuring standard (1) for position measuring systems, produced by the method according to one of claims 1 to 8.

10. Measuring standard (1) for position measuring systems, which has at least one track (2,3) in the track direction (SR) consecutive, magnetically saturated and alternately polarized poles (N, S), characterized in that the successive poles (N, S ) of a track (2, 3) in the track direction (SR) are each separated by a magnetically unsaturated transition region (U).

11. Measurement scale according to claim 10, characterized in that the saturated portions of the track (2, 3) in the tracking direction (SR) are larger than the unsaturated portions.

12. Measuring standard according to claim 10 or 11, characterized in that in transition areas (U) between the poles (N, S) there is at least one partial area (26) with sections which have a polarity opposite to the polarity (N, S) of the surroundings.

13. Measuring standard according to one of claims 10 to 12, characterized in that in the transition region (U) at least a portion (26) is provided with non-magnetized sections.

14. magnetization device for carrying out the method according to one of claims 1 to 8.

15. Magnetizing device (11) for magnetizing measuring graduations (1) for position measuring devices, with a receptacle (H, 24) for at least one measuring graduation (1) and with at least one coarse magnetizing head (12), by the operation acting on the material measure coarse magnetizing field (13) can be produced with a first field direction (F _G ), characterized by at least one fine magnetization head (15), by which a switchable fine magnetization field (15) with a field direction (F _F ) perpendicular to the coarse magnetizing field (13) can be generated during operation.

16. magnetization device (11) according to claim 15, characterized by a sensor (16) through which an actual position (I) of the Grobmagnetisierungsfeld (13) generated poles (N, S) can be detected, and a control device (20), by the detected by the sensor (16) actual position (I) of the poles (N, S) with a desired position (P) comparable and the polarity of the fine magnetizing field (15) in dependence on the actual position (I) switchable is.

17. magnetization device (11) according to claim 15 or 16, characterized in that a plurality of coarse magnetization heads (12) is present, the arrangement in the track direction (SR) of the arrangement of the poles to be magnetized (N, S) in the track direction (SR) ,

18. magnetization device (11) according to any one of claims 15 to 17, characterized in that a plurality of fine magnetization heads (14) is present whose position is assigned to the transition regions (U) between the at least one coarse magnetizing head to be magnetized poles.

19. magnetization device (11) according to any one of claims 15 to 18, characterized in that the at least one fine magnetization head (15) in the track direction (SR) spaced apart poles (N, S) is formed.

20. magnetization device (11) according to one of claims 15 to 19, characterized in that the coarse magnetization head (12) has a permanent magnet.

21. magnetization device (1) according to one of claims 15 to 20, characterized in that the coarse magnetization head (12) and fine magnetization head (15) are integrated.