DE102008059667A1 - Position measuring device for measuring position of movable carriage of machine with respect to machine bed, has scale carrier supported at hinge that pivots carrier around tilting axis, which runs parallel to neutral axis of rotation - Google Patents

Abstract

The device has a scale carrier (4) with a scale structure (40) running along a measuring direction. A movable object (2) i.e. movable carriage is movably guided along the measuring direction at a retainer (1). The scale carrier is supported at a hinge (5) e.g. single-piece solid hinge, that permits pivoting of the scale carrier around a tilting axis with respect to the retainer. A neutral axis of rotation is clamped in the measuring direction, and the tilting axis runs parallel to the neutral axis of rotation. The scale carrier is connected with the movable object by the hinge.

Description

The The invention relates to a position measuring device for determination the position of two mutually movable objects, namely a receptacle and a movable object guided movably thereon, according to the preamble of claim 1.

A such position measuring device comprises a graduation carrier, the at least one graduation structure running along a measuring direction (measuring graduation) which, for position measurement by means of an associated Scanning unit is scanned, and a recording in which the Division carrier is stored.

Of the Division carrier is z. B. as a longitudinally extended Scale formed and can also have two or more partition structures have, each extending along the measuring direction and the spaced apart and juxtaposed transversely to the measuring direction are arranged, for example, an incremental graduation on the one hand as well as an absolutely coded track or a reference mark track on the other hand.

Such arrangements are for example in the Fachbuch Digitale Längen- und Winkelmesstechnik: Position measuring systems for mechanical engineering and the electrical industry by Alfons Ernst (Landsberg / Lech: 1998; 3rd ed.) described.

As in 1a shown are the division carrier 4 and the scanning unit serving for scanning the division structure provided on the graduation carrier 3 in each case on one of the two mutually movable objects 1 . 2 arranged, which is for example a bed 1 and a sled 2 a machine (machine tool) can act. In the example of 1 is the division bearer 4 at the bed 1 attached; the scanning unit 3 will be with the sled 2 relative to the division carrier 4 emotional.

According to 1b can be compromised in such a position measuring device, the measurement accuracy when the serving as a recording of the object object is subjected to a bending load. If the recording is, for example, the machine bed 1 , such bending loads may occur when the associated carriage 2 is moved along the machine bed. Is the division carrier 4 not on the so-called neutral fiber of the machine bed 1 arranged, which usually within the machine bed 1 is located, it comes with a bending of the bed to a compression or elongation of the graduation carrier 4 which acts on the measuring graduation provided on the division graduation and thus impairs the measurement accuracy.

Of the Invention is based on the problem, a position measuring device of the type mentioned above with regard to their insensitivity opposite bends of a receptacle at which the graduation carrier the position measuring device is mounted to improve.

This Problem is inventively by the creation a position measuring device with the features of claim 1 solved.

After that is the graduation carrier over at least one joint (For example, on the movable object) stored, the pivoting of the graduation carrier concerning the admission allows a tilting axis, which lies in a plane that through the measuring direction and a neutral axis of rotation of the position-measuring device is clamped, and which thereby parallel to the neutral axis of rotation runs.

Position-measuring devices with a graduation carrier and a scanning unit an imaginary neutral pivot around which the graduation carrier and can tilt the scanning unit against each other, without that this influences a position measurement. More precise is the neutral one Fulcrum characterized by an infinitesimal tilting of the graduation carrier with respect to the scanning unit around the neutral fulcrum no influence on the result of a Position measurement has, while finite, but how before small tilting movements have a minimal impact on the result of a Position measurement (compared to a tilt around other pivot points) entail. In this context, it should be noted that that in position measuring devices of the type considered here anyway only extremely small tilting of the articulated stored graduation carrier occur.

There In this case, only such tilting play a role, the one perpendicular to the measuring direction and parallel to the plane of the graduation structures lying axis, here is such an axis, which also contains the neutral pivot, as a neutral axis of rotation designated.

The neutral axis of rotation is usually centered in the scanning field of the scanner and in the scanning gap between graduation carrier and scanning unit. According to the above definition, the neutral rotation axis is perpendicular to the measuring direction and together with this creates a plane, which should also be referred to as a neutral level.

To determine the neutral pivot point or the neutral axis of rotation of a position measuring system can proceed as follows:
First, graduation carrier and scanning unit by a defined (small) amount with respect to ei Nes predetermined pivot point slightly tilted to each other, and preferably about an axis passing through that pivot axis, which for the present application is perpendicular to the measuring direction and thereby substantially parallel to the plane of the measurement graduation. Such a tilting movement of the graduation carrier relative to the scanning unit will generally influence the result of a current position measurement; unless the given pivot point is already the neutral pivot point. In the latter case, no further steps to determine the neutral pivot point would be required.

Becomes however, due to the tilting movement of the scale relative to the scanning unit about the given pivot point (not negligible) Influence on the result of the position measurement detected, so the graduation carrier is subsequently (in the tilted State) with respect to the scanning unit (in particular along the measuring direction) shifted until the position measuring device again the position measured value determined before tilting (initial value) displays.

The above-described pivoting movement of the graduation carrier with respect the scanning unit about a predetermined pivot point and the subsequent (linear) shift of the graduation carrier can be (especially for small swivel angles and small displacements) geometrically attributed to a single rotation. The pivot point of the resulting "virtual rotation" is the sought neutral fulcrum, with respect to the graduation carrier and the scanning unit can be tilted towards each other, without - at least with very small tilt angles - the Position measurement would be influenced.

The determination and relevance of the neutral pivot point of a position-measuring device is known in principle to a person skilled in the art, so that in this respect supplementary to the DE 195 11 068 A1 , the DE 199 23 505 A1 , the DE 101 44 659 A1 and the DE 10 2007 035 345 A1 can be referenced.

By the articulated mounting of the dividing structure having graduation carrier a force acting on the recording bending force is converted into a Pivoting movement of the graduation carrier, so that the latter is not exposed to bending forces and that at the graduation carrier planned division structure is not affected.

There the tilting axis of the joint runs parallel to the neutral axis of rotation and is in the neutral plane, a pivotal movement affects of the graduation carrier at small angles not on the result the position measurement.

By an education of the joint to the effect that this translational movements of the graduation carrier relative to the movable object along counteracts the measuring direction, longitudinal movements of the graduation carrier along the measuring direction prevented. Such longitudinal movements could the measurement result distort.

to Forming such a joint is a solid-state joint, For example, a leaf spring, which advantageously parallel to the plane extends through the measuring direction and through the neutral Spindle of the position measuring device is clamped, or a Film hinge.

by virtue of the pivotal mounting by means of a joint should be for the storage of the graduation carrier at least one more, additional warehouse, z. B. in the form of a joint or in Form of a supporting warehouse, such as rollers, Air bearing or plain bearing, be provided, which in particular is designed such that there are a plurality of degrees of freedom of movement of the graduation carrier, and about which of the division carrier z. B. at one together with the moveable object along the recording movable slider is supported. Even such a second camp can as Joint in turn be realized by a leaf spring, however in this case is to be arranged so that the measuring direction is a normal is on the level of this leaf spring.

Prefers lies after the so-called Abbé condition the tilt axis of the first joint also in the so - called working plane, in which the Operation, such. B. the machining of a workpiece or measuring an object, which is done using the data generated by the position measuring device are controlled should. The working plane and the neutral plane defined above fall then together.

is the position-measuring device is associated with a machine tool, for example, edited with a surface of a workpiece is, the working level of the position measuring device is defined as the plane in which the surface to be worked of the workpiece is. The same applies if by means of the position measuring device an object is to be measured.

By the arrangement of the joint, over which the graduation carrier is hinged, or more precisely one defined thereby Tilting or pivoting axis in the working plane is avoided the tilting of the graduation carrier about its pivot axis leads to significant measurement errors.

Furthermore, the joint, over which the graduation carrier is articulated, depending on the boundary conditions in the individual case, be provided at different locations of the graduation carrier, in particular at one end of the graduation carrier or in the central region of the graduation carrier - each considered along the measuring direction.

at Partitioning structures of large extent, which a corresponding require large graduation carrier, due to its weight and its size (lever arm) at articulated bearing tends to vibration can tends a distribution of the division structure on two or more graduation carriers be provided, which are arranged one behind the other along the measuring direction are. To such an arrangement in the transition area to allow positional measurements between the graduation carriers Optionally, multiple scanning units may be used for scanning the graduation carrier can be used.

Further Details and advantages of the invention will become apparent in the following Description of exemplary embodiments with reference to the figures become clear.

It demonstrate:

1a a schematic representation of a position measuring system for determining the position of a movable object in the form of a movable carriage of a machine with respect to a stationary object in the form of a machine bed, wherein a graduation carrier of the position measuring device according to the prior art is mounted on the machine bed;

1b the arrangement 1a wherein during a movement of the carriage bending forces act on the machine bed;

2a a schematic representation of a position measuring system comprising a with its two ends on the one hand on the carriage and on the other hand on a jointly hereby movable slider articulated graduation carrier;

2 B the arrangement 2a during a movement of the carriage;

3 a more detailed illustration of a pivoting movement of the graduation carrier, triggered by bending forces acting during a movement of the carriage on the machine bed;

4a a variant of the arrangement 2a in that a joint associated with the graduation carrier is in the region of the center thereof;

4b a schematic plan view of the arrangement according to 4a ;

5 a variant of the arrangement 2a in that two graduation carriers are arranged one behind the other along the measuring direction;

6a a first detail of the arrangement 2a ;

6b a second detail of the arrangement 2a ;

7 a first modification of the arrangement 2a ;

8th a second modification of the arrangement 2a ;

9 a third modification of the arrangement 2a ;

In the already briefly explained above 1a and 1b represent the machine bed 1 and the sled 2 By way of example, two objects that are movable relative to one another along a direction R and whose position is to be determined by means of an associated position-measuring device. The exemplary embodiments of a position-measuring device described below by way of example for the position measurement on a first object in the form of a machine bed and a second object in the form of a slide can be realized in the same way also on other combinations of two mutually movable objects. The terms "machine bed" and "slide" are therefore to be understood hereinafter only as exemplary characterizations of two mutually movable objects. The statements about the position measuring system to be described in each case apply in the same way also to its application to other mutually movable objects.

To the position of the second object 2 in the form of a carriage relative to the first object 1 in the form of a machine bed for each relative position of these two objects to determine is these objects 1 . 2 a position measuring device 3 . 4 assigned to a graduation carrier 4 and an associated scanning unit 3 includes.

The graduation carrier 4 carries a pitch structure (measurement pitch) extending along the direction of travel R along the carriage 2 concerning the machine bed 1 is mobile. The measuring direction of the position measuring system thus coincides with the direction of movement R, along which the second object 2 in the form of a carriage relative to the first object 1 in the form of a machine nenbettes is movable.

At the graduation bearer 4 provided, along the movement and measurement direction R extending pitch structure may be, for example, an incremental pitch or alternatively an absolutely coded track. A combination of several graduation structures can also be provided, for example a combination of an incremental graduation with an absolutely coded track or with a reference mark track.

Should be the second object 2 in the form of a carriage along several spatial directions with respect to the first object 1 be movable in the form of a machine bed, it would be appropriate to provide appropriate means for position measurement for each direction of movement to be measured.

For a sample one at the graduation carrier 4 provided division structure by means of the scanning unit 3 Different physical measuring principles, such as inductive measuring principles, magnetic measuring principles or photoelectric measuring principles, are available.

Both with regard to the possible embodiments of at least one graduation structure on the graduation carrier 4 as well as with regard to the measuring principles used to scan the graduation structure using a suitable scanning unit 3 be on that Fachbuch Digitale Längen- und Winkelmesstechnik: Position measuring systems for mechanical engineering and the electrical industry by Alfons Ernst (Landsberg / Lech: 1998; 3rd ed.) directed. The embodiments of graduation structures on graduation carriers explained there and the measuring principles described there in the sampling of a graduation structure as well as still further types of graduation structures and measurement principles are generally known in the field of position measurement and can be used within the scope of the embodiments of position measuring devices described herein.

Which concrete embodiment of a division structure and which concrete measuring principle used for scanning the graduation structure is for the following description of the principle of the invention on the basis of several embodiments is not important.

Becomes the second object 2 in the form of a carriage according to the transition from 1a to 1b along its direction of movement R with respect to the first object 1 in the form of a machine bed, act on the first object 1 in the form of the machine bed bending forces, which a - in 1b exaggerated illustration - Bending of the machine bed 1 have as a consequence. As the division carrier 4 in the usual way on the first object 1 is fixed in the form of the machine bed, the graduation carrier - depending on the location of its attachment to the machine bed - stretched or compressed, with corresponding repercussions on the accuracy of the position measurement.

The following is based on the 2a to 9 be represented for different embodiments, as defined by a tiltable or pivotable mounting of the graduation carrier 4 a compression or elongation of the graduation carrier 4 despite a bending of the machine bed 1 avoid it.

According to the embodiment of the 2a and 2 B is the division bearer 4 over a solid-state joint 5 in the form of a leaf spring pivotally movable on the second object 2 articulated in the form of a carriage and thus indirectly on the fixed first object 1 stored in the form of a machine bed. Such a joint 5 allows pivoting movements of the graduation carrier 4 about a tilt axis perpendicular to the movement and measurement direction R, so that the resulting pivotal movement has a component perpendicular to that direction R. The leaf spring 5 is this parallel to the movement and measurement direction R and perpendicular to the plane of the 2a arranged. Alternatively, the joint 5 For example, be formed by a film hinge or a trained otherwise pivot axis.

Furthermore, the joint 5 , z. B. by its design as a leaf spring or as a film hinge, designed such that it translational movements of the graduation carrier 4 concerning the joint 5 and the sled 2 and thus with a resting sleigh 2 also regarding the machine bed 1 counteracts along the measuring direction R, so does not allow (and thus prevented) to a noticeable extent. That is, the joint 5 in particular has no substantial (elastic) deformability along the measuring direction R, ie it is essentially rigid in the measuring direction R.

Here is the graduation carrier 4 according to 2a not only in the area of its one end by means of the solid-state joint 5 in the form of a leaf spring pivoting on the carriage 2 hinged; but in the region of the - viewed along the movement and measuring direction R - the other end of the graduation carrier 4 another articulated bearing is provided, in the present example by way of another leaf spring 6 on a glider 20 who shared the sled 2 along the movement and measuring direction R movable on the first object 1 is arranged in the form of a machine bed. (The second bearing point or the second joint 6 is therefore along the movement and measuring direction R of the first bearing or the first joint 5 beab stands.) At the machine bed 1 is an extension 15 provided, which extends along the movement and measuring direction R and during a movement of the carriage 2 along the machine bed 1 the glider 20 leads, compare 2 B ,

Compared to the first joint 5 , which in particular pivotal movements of the graduation carrier 4 permitting an axis perpendicular to the direction of movement and measurement R extending axis, such that the resulting pivoting movement for small deflections of the graduation carrier 4 is substantially perpendicular to the movement and measuring direction R, the other joint 6 designed so that it mainly counteracts translational movements perpendicular to the movement and measurement direction R and allows compensation movements along the other degrees of freedom that with a pivoting movement at the first joint 5 accompanied. For this purpose, z. B. a second joint 6 forming leaf spring may be arranged so that it extends perpendicular to the movement and measurement direction R, ie that direction R a normal to the leaf spring 6 forms. Of course, the second joint can be realized by other elements than another leaf spring; However, the aim is such an embodiment, the translation movements of the graduation carrier 4 perpendicular to the direction of movement and measurement counteracts R, so preferably prevented.

The result is the division carrier 4 in this case via the joint 5 on the movable object 2 , here in the form of a carriage, pivotally mounted, so that the graduation carrier 4 at a bend of the machine bed 1 - Due to a hereby associated slight inclination of the carriage 2 - Slightly pivoted, but not compressed or stretched, in such a way that the resulting pivotal movement s, compare 2 B , a component perpendicular to the movement and measurement direction R has.

Due to the articulated arrangement of the graduation carrier 4 at the second object 2 in the form of the carriage and thus an indirectly tiltable storage of the graduation carrier 4 with respect to the first object 1 in the form of a machine bed bend the first object 1 not to upsets or strains of the graduation carrier 4 here in the form of a scale, but only to a tilting or pivoting movement, which has no effect on the structure of the graduation carrier 4 provided measuring graduation, so that the measurement accuracy of the position measuring device is not affected.

It should be noted that in practice only very small deflections of the first object 1 occur in the form of a machine bed (which in 2 B are exaggerated for better visualization). Accordingly, only very small deflections (tilting or pivoting movements) of the graduation carrier occur 4 on.

It should be added in terms of the arrangement and design of the two joints 5 . 6 on the 6a and 6b directed.

6a shows a schematic plan view of the articulated connection of the graduation carrier 4 on the sledge 2 via a joint formed by a leaf spring 5 , It is clear that in this embodiment, the leaf spring 5 extending in a plane that runs parallel to the plane in which the at the graduation carrier 4 provided and in 6a schematically indicated measuring graduation 40 lies.

6b shows for a more detailed illustration a front view of the arrangement of 2a in the area of the second joint 6 about which the division bearer 4 articulated (in the area of his sled 2 remote end) to a slider 20 tethered, being that joint 6 is designed such that there are translations of the graduation carrier 4 concerning the slider 20 in the plane perpendicular to the movement and measurement direction R, ie in the sheet plane of the 6b , counteracts.

Based on a synopsis of 2a with the 6a and 6b it becomes clear that the first joint 5 forming leaf spring and the second joint 6 forming leaf spring are oriented perpendicular to each other, namely the first joint 5 forming leaf spring parallel to the plane of the at least one division structure 40 and the second joint 6 forming leaf spring perpendicular to the plane of the division structure 40 ,

A possible arrangement of at least one division structure 40 at the graduation carrier 4 is doing in the 2a . 2 B as well as the associated detailed representations of 6a and 6b shown only as an example. A comparable arrangement of a division structure on the graduation carrier 4 can also be provided in the other embodiments. In principle, the arrangement of a dividing structure on a graduation carrier, be it an elongate scale or an annular dividing disk, is part of the specialist knowledge and therefore requires no further explanation.

In 3 is schematically the articulated linkage of the graduation carrier 4 on a sledge 2 about a joint 5 , shown here in the form of a leaf spring, whereby at one edge of the graduation carrier 4 a pivoting or tilting axis K is defined. If this is in the working level A of the position measuring device, then repercussions of a tilting or Pivoting movement of the graduation carrier 4 (corresponding to a transition of the graduation carrier in the with 4 * characterized position) is minimized to the result of a position measurement. The so-called Abbé condition is then met.

Is the work plane A ', as in 3 alternatively shown, on the other hand perpendicular to the movement and measurement direction R by an amount d of that tilt axis K spaced apart, so leads to a tilting of the graduation carrier 4 , as in 3 based on the transition to the tilted position 4 * shown, at a tilt angle α (for very small tilt angle) to a measurement error of size l = α · d (with sin α ≈ α for small α). The Abbé condition is then not met.

Should the graduation carrier provided with the at least one graduation structure 4 consist of a very thin material, so may for a pivotable mounting of the graduation carrier 4 its fixation on a thicker carrier body may be required to ensure the necessary inherent stability.

In the 7 to 9 is for a position measuring device in the 2a and 2 B shown type for different positions of the neutral axis of rotation x shown as the tilting or pivot axis K of the graduation carrier 4 each is to be arranged concrete.

It is in the 7 to 9 a working level A respectively identified by the fact that there is a processing facility 8th for processing one on the slide 2 arranged workpiece or for measuring one on the carriage 2 arranged object is shown. At the processing facility 8th For example, it may be a laser having a downstream lens for focusing a laser beam onto one on the carriage 2 lying, to be machined workpiece such. B. a sheet metal part act. But it can also be means for exposing a wafer or other work equipment, the processing of a on the slide 2 serve lying workpiece. The working plane A is then immediately above the surface of the carriage 2 on which the workpiece to be machined or the object to be measured is placed.

In the 7 to 9 Furthermore, in the working plane A, the neutral rotation axis x of the position-measuring device is also indicated as a cross in a circle, with respect to which there is a relative pivoting movement of graduation carriers 4 and scanning unit 3 does not lead to substantial measurement deviations. Both this neutral axis of rotation x and the working plane A, which coincides with the plane defined by the neutral axis of rotation x and the measuring direction R neutral plane, here perpendicular to the plane of the drawing 7 to 9 ,

In the 7 to 9 is in each case a first object 1 represented in the form of a machine bed on which a second object 2 is movably arranged in the form of a carriage along a direction of movement R.

At the sled 2 is each about a joint 5 (Solid-state hinge in the manner of a film hinge), which defines a tilting or pivoting axis K, a graduation carrier 4 articulated tiltably, the at least one division structure by means of an associated scanning unit 3 is palpable. This tilting axis K runs parallel to the neutral pivot axis x of the position-measuring device and lies in its neutral plane.

The scanning unit 3 is here before the first object 1 in the form of a machine bed side facing away from the graduation carrier 4 ; however, it is common with the machine bed 1 arranged stationary, so that by scanning the on the graduation carrier 4 provided division structure by means of the scanning unit 3 Position changes of the carriage 2 concerning the machine bed 1 are detectable.

The respective joint 5 about which the division bearer 4 tiltable on the movable second object 2 is articulated in the form of the carriage is in each case carried out so that it defines a perpendicular to the movement and measuring direction R extending tilting axis K and tilting movements of the graduation carrier 4 around that axis K - for small deflections from the into the 7 to 9 illustrated starting position of the graduation carrier 4 - take place in each case substantially perpendicular to that direction R.

The graduation carrier 4 is in the arrangements of the 7 to 9 in the area of one of the tilting joint 5 spaced end portion in each case additionally via a bearing 7 stored, as above on the basis of 2a and 2 B already described in detail. It is shown here a simple roller bearing; the use of other bearings is also possible, as mentioned above.

The arrangements of 7 to 9 differ in the position of the neutral axis of rotation x and thus the position of the neutral plane (which coincides with the working plane A) of the respective position measuring device, which in turn of the specific embodiment of the graduation carrier 4 , the dividing structure (s) provided thereon and the scanning unit 3 depends.

In the arrangement according to 7 is the neutral axis of rotation x in one of the scanning unit 3 to facing surface of the graduation carrier 4 ; in the arrangement according to 8th is the neutral axis of rotation x in the scanning unit 3 and in the arrangement according to 9 she lies in the graduation carrier 4 , In all three cases, the joint defining the tilting axis K is 5 each configured so that the pivot axis K is in the respective neutral plane and parallel to the axis of rotation x.

Thus, it is with a suitable arrangement and design of the articulated mounting of the graduation carrier 4 serving joint 5 as based on the 7 to 9 shown, readily possible to realize a desired arrangement of the respective tilt axis K in the working plane A and in the neutral plane of the position measuring device.

As based on the 4a and 4b becomes clear, which must be a tilting axis K defining first joint 5 about which the division bearer 4 articulated, by no means mandatory at one end of the graduation carrier 4 be provided. According to the 4a and 4b , in which 4b a plan view of the arrangement of 4a without the machine bed 1 represents, is said joint 5 rather in the middle area of the graduation carrier 4 intended. This is indicated by the second object 2 in the form of a carriage, a connecting element 22 which is the division carrier 4 overlaps and on which next to both sides of the graduation carrier 4 to form a joint in each case a leaf spring 5 is arranged, in turn, via each a carrier-side connecting element 42 with the graduation carrier 4 communicates.

According to 5 can be provided (to avoid the use of graduation carriers, for example in the form of a scale along the direction of movement and measurement R, which have a particularly large extent and would therefore be particularly sensitive to vibration in articulated storage), at least two graduation carriers 4a . 4b , each of which has a division structure extended along the movement and measurement direction R, to be arranged one behind the other along that direction R, that is to say as a result distributing a division structure over a plurality of division carriers.

The first graduation carrier 4a is then in the already using the 2a and 2 B way described above a first joint 5a pivotable on the movable second body (slide 2 ) and with its other end on another (second) joint 6a , which counteracts translational movements perpendicular to the movement and measurement direction R, with a slider 20a connected, as well as the sled 2 movable on the first body (machine bed 1 ) is guided.

At that glider 20a is according to 5 via an additional first joint 5b which as well as the above first joint 5a defines a pivot axis, the second graduation carrier 4b hinged, which in turn at the other end via a second joint 6b , which counteracts translations perpendicular to the movement and measurement direction R, hinged to a slider there 20b is connected.

In summary, so in the arrangement of 5 two graduation carriers 4a . 4b arranged in the form of two scales along the direction of movement and measurement R one behind the other and thereby each articulated in such a way that the respectively associated first joint 5a . 5b Translational movements of the respective graduation carrier 4a . 4b counteracts along the movement and measuring direction R, but in particular a pivoting movement of the respective graduation carrier 4a . 4b perpendicular to the movement and measurement direction R permits.

In addition, the two graduation carriers 4a . 4b at one of the respective first joint 5a . 5b along the movement and measuring direction R spaced location on a respective second joint 6a . 6b articulated, which translational movements of the respective graduation carrier 4a . 4b transversely to the direction of movement and measurement R counteracts to prevent them.

In such an arrangement, care must be taken to ensure that the transitional area between the two graduation carriers 4a . 4b a continuous position measurement is not hindered. That is, it must be ensured that a position measurement is possible even if one of the graduation carriers 4a . 4b associated scanning unit 3 in a scanning process, the transition region between the two graduation carriers 4a . 4b scans.

If it should not be possible to provide a dividing structure with sufficient accuracy in the transitional area, the division carriers can 4a . 4b two scanning units 3 are assigned, which are arranged one behind the other along the movement and measurement direction R. If, in a position determination, the one scanning unit in a scanning on the transition region between the two graduation carriers 4a . 4b then accesses the outputs of the other of the two scanning units 3 be used for a position determination.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19511068 A1 [0016]
• - DE 19923505 A1 [0016]
• - DE 10144659 A1 [0016]
• - DE 102007035345 A1 [0016]

Cited non-patent literature

• - Fachbuch Digitale Längen- und Winkelmesstechnik: Position measuring systems for mechanical engineering and the electrical industry by Alfons Ernst (Landsberg / Lech: 1998; 3rd ed.) [0004]
• - Fachbuch Digitale Längen- und Winkelmesstechnik: Position measuring systems for mechanical engineering and the electrical industry by Alfons Ernst (Landsberg / Lech: 1998; 3rd ed.) [0048]

Claims (16)

Position measuring device, with - a graduation carrier ( 4 . 4a . 4b ), the at least one along a measuring direction (R) extending graduation structure ( 40 ), which for position measurement by means of an associated scanning unit ( 3 ) is scannable, and - a recording ( 1 ), on which a movable object ( 2 ) is movably guided along the measuring direction (R), wherein the scanning unit ( 3 ) on the one hand and the graduation carrier ( 4 . 4a . 4b ) On the other hand, each one of the two components recording ( 1 ) and movable object ( 2 ), characterized in that the graduation carrier ( 4 . 4a . 4b ) via at least one joint ( 5 . 5a . 5b ), which pivoting the graduation carrier ( 4 . 4a . 4b ) concerning the recording ( 1 ) about a tilting axis (K), and that the tilting axis (K) lies in a plane which is spanned by the measuring direction (R) and a neutral rotation axis (x) of the position-measuring device, and the tilting axis (K) parallel to the neutral Rotary axis (x) runs. Position measuring device according to claim 1, characterized in that the graduation carrier ( 4 . 4a . 4b ) over the joint ( 5 . 5a . 5b ) with the movable object ( 2 ) connected is. Position measuring device according to claim 1 or 2, characterized in that the joint ( 5 . 5a . 5b ) Translational motions of the graduation carrier ( 4 . 4a . 4b ) with respect to the movable object ( 2 ) counteracts along the measuring direction (R). Position measuring device according to one of the preceding claims, characterized in that the joint ( 5 . 5a . 5b ) is formed as a one-piece solid-body joint. Position measuring device according to claim 4, characterized in that the joint ( 5 . 5a . 5b ) is formed by a leaf spring or a film hinge. Position measuring device according to one of the preceding claims, characterized in that the graduation carrier ( 4 . 4a . 4b ) additionally by means of a warehouse ( 6 . 6a . 6b . 7 ) supported along the measuring direction (R) of the joint ( 5 . 5a . 5b ) is spaced. Position measuring device according to claim 6, characterized in that the bearing ( 6 . 6a . 6b . 7 ) is designed such that it translational movements of the graduation carrier ( 4 . 4a . 4b ) counteracts perpendicular to the measuring direction (R). Position measuring device according to claim 6 or 7, characterized in that the graduation carrier ( 4 . 4a . 4b ) over the camp ( 6 . 6a . 6b ) at one together with the movable object ( 2 ) along the picture ( 1 ) movable slider ( 20 . 20a . 20b ) is supported. Position measuring device according to one of claims 6 to 8, characterized in that the bearing ( 6 . 6a . 6b ) is formed as another joint. Position measuring device according to claim 9, characterized in that the bearing ( 6 . 6a . 6b ) is formed by a solid-state joint, in particular in the form of a leaf spring. Position measuring device according to one of claims 6 to 8, characterized in that the bearing ( 7 ) is a plain bearing, a roller bearing or an air bearing. Position measuring device according to one of the preceding claims, characterized in that the plane spanned by the measuring direction (R) and the neutral axis of rotation (x) of the position measuring device, in which the joint ( 5 . 5a . 5b ) coincides with a working plane (A) in which a with the relative movement of the movable object ( 2 ) concerning the recording ( 1 ) associated machining process takes place, which by measuring the position of the movable object ( 2 ) concerning the recording ( 1 ) is controllable by means of the position measuring device. Position measuring device according to one of the preceding claims, characterized in that the joint ( 5 . 5a . 5b ) at an end portion of the graduation carrier ( 4 . 4a . 4b ) is arranged. Position measuring device according to one of claims 1 to 12, characterized in that the joint ( 5 ) in a central region of the graduation carrier ( 4 ) is arranged. Position measuring device according to one of the preceding claims, characterized in that in the position measuring device along the measuring direction (R) at least two graduation carriers ( 4a . 4b ) are arranged one behind the other, each on the movable object ( 2 ) or a jointly movable slider ( 20a ) via at least one joint ( 5a . 5b ), which pivoting the graduation carrier ( 4a . 4b ) concerning the recording ( 1 ) allows. Position measuring device according to one of the preceding claims, characterized in that the position measuring device as a Län measuring device and the division carrier ( 4 . 4a . 4b ) is formed as a scale.