DE102009023395A1 - Code disk for encoder of electric motor, has circular scan area, in which scale is formed by spiral and parallel bars, and spiral bars of scale are formed such that bars cut imaginary straight line - Google Patents

Abstract

The code disk (11) has a circular scan area (12), in which a scale is formed by spiral and parallel bars (13). The spiral bars of the scale are formed such that the bars cut an imaginary straight line (14). The tangents (16), bordered on the spiral bars in intersections (15), run perpendicular to the imaginary straight line and parallel to one another. An independent claim is also included for an encoder, particularly optical encoder and inductive encoder.

Description

The The present invention relates to a code disk for a Encoder with a circular scanning area, in which a scale of essentially spiral, is formed parallel lines.

Usually are code discs for encoder or encoder such designed to be the scale used by a sensor of the Encoder is scanned by running radially outward Dashes is formed. The strokes are not parallel to each other but run concentrically, the extension of the strokes passes through the center of the code disc. The strokes of the scale are thus as circle segments or wedge-shaped Segments formed. To a simple scan of the scale With a sensor to enable, are therefore code discs known, which have many strokes. In this case, converge the circle segments to almost parallel lines.

adversely on these code discs is that they only for very large or suitable for optical encoders. Small designs such code discs are not feasible.

It is also known to form encoder so that the sampling of Codewheiben not in the axial, but in the radial direction of the Code disc is done. However, the length of these encoders increases, The production becomes more complicated and therefore the costs increase.

Further There are encoders that have predistorted sensors, so the Sensors of the circular shape of the code disk or the strokes to be scanned consequences. However, these sensors have only a low flexibility can and therefore only for a code disk diameter be used.

It There are also smart sensors available, both can read out concentric circle segments as well as parallel lines. However, these sensors are relatively expensive.

In the US 5,017,776 An optical encoder is disclosed in which the scale of the code disc to be scanned is formed by helical windows and spokes of identical shape. The front edges and trailing edges of the windows, which are viewed in the direction of rotation of the disk, run essentially parallel to one another and are each designed as sections of an Archimedean spiral. If the radius of the Archimedean spirals is sufficiently large that the Archimedean spirals are almost tangential, the spirals are essentially equidistant from each other. However, especially in cramped conditions on the code disk, the course of the edges along the Archimedean spiral is not optimal. This is especially true with code disks having an inner radius which is close to the optical radius of the code disk. The optical radius k of the code disk is defected in this context as follows: k = at 2π . where a is the distance of the bars of the scale from one another and n is the number of bars of the scale. If the inner radius of the code disk is close to the optical radius, then the bars of the scale formed along the Archimedean spirals are no longer equidistant from each other and clear signals are no longer generated.

It Therefore, the object of the present invention is a code disk to provide that overcomes the disadvantages of the previously known code disks, so that reliable signals of good quality are provided can be.

For this is inventively provided that the spiral Dashes of the scale are designed such that they to cut an imaginary straight line in such a way that those in the intersections perpendicular to the spiral lines applied tangents to the imaginary line and parallel to each other.

Thereby, that the spiral lines, or the applied to them Tangents, in the region of the imaginary lines parallel to each other run and thus are equidistant from each other, can the rotational movements of the code disc in an equidistant Linear scale can be implemented. It can therefore be a linear sensor be used for scanning the code disk. By the straightforward Line can be so even at small radii of the code disc, d. H. at radii close to the optical radius of the code disk lie, even interpolation signals generated become. In addition, the code disk can be used with all types of encoders in which a scale is scanned locally. The code disk can therefore be used for inductive encoders, optical Encoder (reflective and transmissive) and capacitive encoder used become.

In an advantageous embodiment it can be provided that the imaginary straight line forms a circle tangent to a circle with the radius concentric with the annular scanning region k = at 2π where a is the distance between the bars of the scale and n is the number of bars of the scale. If the bars of the scale are trained as circle involutes, they fulfill this requirement. The linear sensor can then easily along a tangent z. B. is applied to the inner edge of the annular scanning area, aligned.

gebildet sind, mit k = a·n2π , wobei a der Abstand zwischen den Strichen des Maßstabs, n die Anzahl der Striche des Maßstabs und C eine Konstante ist. Durch diese Gleichung wird eine bevorzugte Form der als Kreisevolventen ausgebildeten spiralförmigen Striche des Maßstabs beschrieben. Der Radius r der Codescheibe darf dabei nicht kleiner als k werden, da sonst der Radikand negativ wird. Dabei entspricht k dem optischen Radius der Codescheibe. Auf diese Weise können die spiralförmigen Striche einfach in der gewünschten Kurvenform erzeugt werden.In a preferred embodiment of the invention it is provided that the helical bars of the scale according to the equation

are formed with k = at 2π . where a is the distance between the bars of the scale, n is the number of bars of the scale, and C is a constant. This equation describes a preferred form of helical bars of the scale formed as circle involutes. The radius r of the code disk must not be smaller than k, otherwise the radicand becomes negative. Here, k corresponds to the optical radius of the code disk. In this way, the spiral strokes can be easily generated in the desired curve shape.

It can also be provided that the spiral lines scale formed as a pseudo-random-cyclic code are. It can then enter with a single track on the code disk Absolute encoder or an encoder can be realized with index. Thereby the absolute position of the shaft can be specified on which the code disk is attached.

In Still another advantageous embodiment be provided that the track width, the track pitch or the intensity of the scale is modulated. This will improve portability allows the signals.

Further The invention also relates to an encoder with a preceding described code disk for mounting on a shaft and with a Linear sensor for scanning the scale of the code disc. By the invention already described Training the scale of the code disk, which makes it possible Rotational movements in an equidistant linear scale can implement relatively inexpensive linear sensors be used as motion detectors. Because the scale the code disk is formed by parallel lines can even with small circular code discs linear sensors be used, whereby for micro motors encoders with relatively coarse line widths can be used without that a radial scan of the code discs is required.

In In an advantageous variant it can be provided that the linear sensor aligned along the imaginary line. In the area of the imaginary Straight lines run the spiral lines of the scale exactly parallel to each other, so that very accurate signals are generated can.

It But it can also turn out to be positive, the linear sensor slightly twisted in relation to the imaginary line. The angle between the longitudinal extent of the linear sensor and the imaginary line is preferably about 0.10 to 5 °. This can be slightly rounder signals generated (anti-aliasing).

In a preferred embodiment it can be provided that the imaginary straight line forms a circle tangent to a circle with the radius k = at 2π where a is the distance between the bars of the scale and n is the number of bars of the scale. The strokes are then designed as circle involutes, so that simply an equidistant distance between the strokes can be set and the scale can be easily generated.

In Another variant may be provided that the encoder is designed as an optical encoder, wherein the code disc a Outside diameter in the range of about 2 mm to 140 mm, and the width of the bars of the scale of the code disk is in a range of about 0.05 mm to 1 mm. That's it possible, optical encoders in high-resolution variants for micro and small motors. The scale the code disk is finely structured and is formed, for example, by electroforming, Sputtering, photolithography, photoresist or other fine structuring measures produced. The reading of the scale is done with a integrated circuit. Especially for code discs, the in the upper part of the specified diameter sizes lie, arises by scanning many successive Dashes of the scale a special advantage. It is then one better phase determination for the interpolation possible, and there is a possibility of longer pseudo-random codes or to scan other codes.

It But it can also be provided that the encoder as optical Encoder is formed, wherein the code disc has an outer diameter in the range of about 30 mm to 500 mm and the width of the Dashes of the scale of the code disc is more than 1 mm. This way, you can make bigger, more discreet built optical encoder can be produced. The production of Codewheel is cast, for example, by injection. As a code disk but also a structured plastic part or a stamped part can be used. As a sensor of the encoder then used discretely constructed photodiodes. This is a cheap one Production of the encoder possible. Due to the special spiral shape but the dashes of the scale of the code disc is still achieved a high signal accuracy.

Advantageously, it can also be provided that the encoder is designed as an inductive encoder, wherein the code disc an outer diameter in a range of about 10 mm to 150 mm and the width of the bars of the scale of the code disk in a range of about 0.1 mm to 3 mm, preferably 1.2 mm. The code disc thus has very filigree structures. It is thus possible to produce highly integrated encoders with filigree structures. Thanks to the special spiral shape of the scales of the scale specified above, very accurate signals are generated.

In Yet another embodiment may be provided that the encoder is designed as an inductive encoder, wherein the Outer diameter of the code disk in a range of about 30 mm to 500 mm and the width of the bars of the scale is greater than 3 mm and maximum about 30 mm. Here, too, can be larger inductive Encoder are provided, which are then discretely constructed and having discretely arranged coils. By using the code disc according to the invention with the new spiral shape of the bars of the scale it is So possible, inexpensive inductive encoder produce, yet have a high signal accuracy.

Further The invention also relates to an electric motor with a Code disc described above. The linear sensor of the encoder can be external to the engine, which is very popular with printers and motors used in hermetically sealed housings. It is then an open or externally realized Encoder. This encoder has the advantages already described on.

In A further variant may be provided that an electric motor has an encoder described above. In this case, the Encoder integrated in the electric motor. The electric motor has so the advantages already described. So it is possible To provide micromotors, the encoders with a relatively coarse Have line width and can be scanned with a linear sensor. This provides simple, low-cost engines.

in the Below, the invention with reference to a drawing explained. Show it:

1 Coded disc with a scale according to the prior art,

2 Code disc with the scale according to the invention,

3a Enlargement of a section of the scale 1 .

3b Enlargement of a section of the scale 2 .

4 Code disc with identification of the sensor positions,

5 further embodiment of a code disc according to the invention,

6 optical encoder with a code disk according to the invention, and

7 inductive encoder with a code disk according to the invention.

The Coded discs or encoders are not shown to scale.

1 shows a code disc 1 with an annular scanning area 2 , In the annular scanning region 2 is a scale of essentially helical, parallel lines 3 arranged. The spiral lines 3 are like in the US 5,017,776 described trained. Each of the spiral strokes 3 follows the equation r = k · φ. Where r is the radius and φ is the angle of rotation. This equation represents an Archimedean spiral. Each of the strokes 3 is thus formed as part of an Archimedean spiral. An Archimedean spiral represents the trajectory of a point traveling at a constant velocity on a straight line passing through the center of a circular disk, while the disk is rotated at a constant speed. An Archimedean spiral is characterized by the fact that its winding distance is constant. If the radius r assumes large values, so that the Archimedean spiral already runs almost tangentially to a circle, then the lines are essentially equidistant from each other. The distance of the lines to each other is determined in such a way that first the solder is cut on the lines and the distance between two lines corresponds to the distance of the solder between the two lines. Especially for small radii r there is no common solder for adjacent strokes, which are formed according to an Archimedean spiral. These lines are therefore not equidistant from each other.

2 shows a code disc 11 according to the present invention. The code disc 11 also includes an annular sensing region 12 in which parallel to each other, helical strokes 13 are formed. Also the code disc 11 is designed as a circular ring. The spiral lines 13 Form a scale that can be read by a sensor of an encoder. Each of the strokes 13 has a constant distance a to the next stroke 13 on, by an angle Δφ from the first bar 13 is moved. The angle Δφ is given by the number n of bars of the scale and is given by the equation Δφ = 2π n Are defined. The strokes 13 Thus, each equidistant to each other, so that over the entire width of the scanning area 12 the distance between two adjacent lines 13 is constant. The distance between two bars 13 is determined so that first the lot is felled on the two strokes. The perpendicular is perpendicular to both strokes 13 , The distance between the strokes 13 then the stretch is on the lot between the two intersections of the lot with the strokes 13 ,

The spiral lines 13 of the scale are thus designed so that they are an imaginary line 14 cut in such a way that in the intersections 15 to the spiral lines 13 created tangents 16 perpendicular to the imaginary line 14 and run parallel to each other. The tangents 16 are therefore equidistant to each other. Such an imaginary line exists for any juxtaposed strokes 13 , Because the tangents 16 Equidistant to each other, they can be read with a linear sensor. As a sensor of an encoder with the code disk according to the invention, therefore, a linear sensor can be used.

gebildet sind. Die Konstante k ist folgendermaßen definiert: k = a·n2π . k entspricht dem Minimalradius, den der innere Rand des kreisringförmigen Abtastbereichs 12 mindestens annehmen muss, da sonst der Radikand der obigen Gleichung negativ wird. Dabei ist a der gewünschte Abstand zwischen den Strichen 13 des Maßstabs und n die Anzahl der Striche 13 des Maßstabs. Die gedachte Gerade 14 ist dann vorzugsweise eine Tangente an einen Kreis mit dem Minimalradius k.Preferably, the helical strokes 13 of the scale trained as Kreisvolventen. This can be achieved by making the spiral strokes 13 of the scale according to the equation

are formed. The constant k is defined as follows: k = at 2π , k corresponds to the minimum radius that the inner edge of the annular scanning region 12 at least, otherwise the radical of the above equation becomes negative. Where a is the desired distance between the bars 13 scale and n the number of strokes 13 of the scale. The imaginary straight line 14 is then preferably a tangent to a circle with the minimum radius k.

The spiral path of the circle involutes or spiral lines 13 can be described by the development of circle tangents on the outside of a circle. When a tangent is rolled to a circle on the circle, the point of the circle tangent to which the circle tangent originally attached to the circle describes a spiral curve, the circle involute. In the present case, the circle on which the circle tangent is unrolled, a radius k, with k = at 2π ,

As already described, the constant k represents the optical radius or the minimum radius of the code disk 11 The inner radius r _{i of} the scanning area 12 the code disc 11 must not be smaller than the optical radius k, otherwise the radical of the equation given above would be negative. The code disk according to the invention 11 is characterized by the fact that even in the region where the code disc's radius is very close to the optical radius k, good sampling of the code disc is still possible.

3a shows an enlarged portion of the code disk 1 according to the closest prior art 1 , 3b shows an enlarged portion of the code disc according to the invention 11 out 2 , In this comparison, the difference between the scale known from the prior art according to 1 and the scale according to the invention, as described in 2 shown clearly.

Though Circle curves and Archimedean spirals approach with increasing number of turns more and more to each other. But especially in the small angle range and small radii are strong differences between the course of a circle involute and an Archimedean spiral present.

As in 3b shown are the spiral lines 13 the scale of the code disc 11 designed so that they with an imaginary line 14 intersections 15 exhibit. The imaginary straight line 14 is preferably a circular tangent to the inner circular edge of the scanning area 12 , This inner circle of the scanning region preferably has the radius k, ie the minimum radius. In the intersections 15 can be tangents 16 to the spiral lines 13 be created. These tangents 16 are perpendicular to the imaginary line 14 as well as parallel to each other. The distance a between two adjacent tangents 16 is always the same and corresponds to the distance a between two adjacent bars 13 , The tangents 16 are therefore equidistant.

As in 3a This is in the known from the prior art scale of the code disk 1 not the case. Here are the intersections of the lines 3 with an imaginary straight line 4 , or the circle trainee, to the strokes 3 created tangents 6 not parallel to each other. The tangents 6 close with the imaginary line 4 different angles, and therefore are not equidistant from each other.

From this comparison, it is therefore easy to see that the scale with the spiral lines 13 makes the present invention rotational movements in an equidistant linear scale feasible. This makes it possible to use relatively inexpensive linear sensors for scanning the scale of the code disk 11 use. The linear sensors usually have a certain longitudinal extension and therefore touch the strokes 13 applied tangents. The determined spiral shape of the strokes 13 is easy to use even for code disks in the tightest of conditions. The code disc 11 with a scale of spiral, substantially parallel lines 13 as they are in the 2 and 3b can be used in all types of encoders in which a scale is scanned locally. An appropriately designed code disk can therefore be used for inductive, optical (reflective and transmissive), capacitive and eddy-current encoders.

4 shows a further embodiment of a code disc according to the invention 11 ' , The code disc 11 ' essentially corresponds to the code disk already described, so that the same reference numerals are used for the same components or elements. The code disc 11 ' has an annular scanning region 12 on. In the scanning area 12 are eight spiral-shaped, parallel lines 13 formed the scale of the code disk 11 ' form. The angle Δφ to the adjacent bars 13 are each shifted to each other, that is 45 °. The distance a between the bars 13 is 1.2 mm. The sensitivity of the code disk 11 ' is therefore 37.5 ° / mm.

As already described, the spiral lines are 13 Scale formed such that they intersect an imaginary straight line such that in the intersections of the spiral lines 13 applied tangents are equidistant to each other and perpendicular to the line and parallel to each other. The spiral lines 13 are therefore again trained as circle involute. The circle involutes follow the equation already given. Will the code disk 11 ' in an encoder sets, then the respective sensor of the encoder is arranged in the region of a first of the imaginary line. The imaginary straight line is preferably again as a tangent to one with the annular scanning region 12 formed concentric circle. Preferably, the circle has the radius k, where k is the minimum radius. In 4 this circle corresponds to the inner edge of the scanning area 12 ,

In 4 two sensor positions are shown. The rectangle represents the possible position of an optical linear sensor 17 dar. The optical linear sensor 17 spans almost the entire width of the circular scan area. The linear sensor 17 then detects a majority of the spiral lines 13 so that the code disk 11 ' can be reliably scanned even with contamination and reliably a position signal can be generated. The square indicates the possible position of an inductive linear sensor 18 at. The inductive linear sensor 18 is along another of the imaginary straights 14 arranged, which is formed such that the spiral to the strokes 13 in the intersections with the line 14 applied tangents perpendicular to the further straight line 14 and parallel to each other and thus are arranged equidistant from each other. Also the other imaginary straight line 14 is preferably as a tangent to one with the annular scanning region 12 concentric circle with the minimum radius k, particularly preferably as a tangent to the inner edge of the scanning 12 educated. The optical linear sensor 17 and the inductive linear sensor 18 so touch the tangents 16 at the intersections of the spiral lines or circle involutes 13 with the imaginary line on the lines 13 issue. This produces an accurate, reliable signal.

By scanning the parallel tangents 16 For example, a linear sensor can be used even on small circular code discs. The outer diameter because of the code disc 11 ' is freely selectable in wide ranges and is preferably in a range of about 2 mm to 140 mm. For example, an encoder with a code disc with 3 mm outer diameter can be realized as an optical encoder with a 256 dpi sensor. An encoder with a code disc with 10 mm outer diameter can be realized as inductive encoder with 1.2 mm pitch. Furthermore, for example, an optical encoder with a code disk with 30 mm diameter can be realized with pseudo-random-cyclic code and a 180 dpi track. As 4 shows, the code disks can 11 ' be used with relatively coarse line widths even for micro motors, without a radial scanning of the Co descheiben is required. But there are also code discs with larger outer diameters possible.

5 shows yet another embodiment of a code disk 11 '' for an inductive encoder. This encoder is preferably used in a flat motor. The code disc 11 '' is formed by a printed circuit board (PCB) attached to the rotor of the flat motor. The code disc 11 '' has an outer diameter of about 90 mm. The scale of the code disc 11 '' consists of 200 strokes 13 together. The distance a between the bars 13 is about 1.2 mm. The code disc 11 '' therefore has a sensitivity of 1.5 ° / mm. The angle Δφ to the adjacent bars 13 are each shifted to each other, here is 1.8 °. The optical radius k is here 38.2 mm and does not correspond to the inner radius of the scanning range of the code disk, but was chosen so that a round line number results. The active sensor area is approx. 2.5 mm × 2.5 mm. Preferably the scale formed by a on the base material of the circuit board (usually FR4, ie impregnated with epoxy resin fiberglass panels) applied copper layer.

folgen, ist auch dann möglich, wenn weniger Striche verlangt werden als theoretisch möglich sind, wo also die Striche schräg statt konzentrisch verlaufen.Even for large code disks worth the mentioned procedure. The formation of the scale of the code disk 11 '' by parallel helical strokes corresponding to the equation

is possible even if fewer strokes are required than are theoretically possible, ie where the strokes are oblique instead of concentric.

As already described, an encoder with an inventive Code disc for scanning the scale of the code disc be equipped with a linear sensor. The linear sensor of the Encoder is then preferably arranged to the scale the code disc scans along the imaginary line and therefore aligned along the imaginary line. But it can too be provided, the linear sensor slightly twisted to the imaginary To arrange straight lines. It will then get something rounder signals (Anti-aliasing). The imaginary line is preferably as a tangent formed on a circle with the minimum radius k.

The The invention also relates to an optical encoder the code disk according to the invention and with a Linear sensor for reading the code disc. Such an optical Encoder can be used as a high-resolution variant for and small motors are manufactured. The code disc is as above described trained and has an outer diameter in the range of about 2 mm to 140 mm. The width of the strokes the scale of the code disc lies in one area from 0.05 mm to 1 mm. The code disc is then so finely structured and is, for example, by electroforming, sputtering, photolithography, Photoresist or other fine patterning made. The sensor of the optical encoder is in this case by a integrated circuit formed.

In front especially with code discs with an outer diameter in the Upper half of the specified range is created by the Scanning many successive bars of the scale a special advantage. It is then a better phase determination possible for interpolation, and there is also the possibility to sample longer pseudo-random or other codes.

6 shows an example of a high-resolution optical encoder 19 with a code disk according to the invention 11 ''' , The code disc 11 ''' again comprises an annular scanning region 12 ''' with spiral lines 13 , The spiral lines 13 are again as circle involutes to the inner circular edge of the scanning area 12 ''' educated. The circle involutes, or the spiral lines 13 follow the equation already given. The encoder 19 is also circular and has an opening in the middle 20 on, so the encoder 19 can be plugged onto a shaft. The scanning range 12 ''' the code discs 11 ''' is in the outer area of the encoder 19 arranged. The one next to the opening 20 arranged area of the encoder 19 has no measuring standard. The code disc 11 ''' is preferably formed as a disk with 256 dpi. The line spacing of the bars 13 the scale is 0.1 mm. The encoder 19 is thus implemented as an encoder with a 256 dpi sensor. The diameter of the code disc 11 ''' is preferably 3 mm. The shaft to which the encoder 19 can be plugged, has a shaft diameter of 1 mm. On the encoder 19 is the position of the linear sensor 17 specified. The linear sensor 17 is aligned along the imaginary line, which is designed so that the tangents to the spiral lines 13 in the intersections of the spiral lines 13 with the imaginary line are equidistant to each other. Preferably, the imaginary line is a tangent to the inner edge of the scanning area 12 ''' the code disc 11 ''' , or to one with the annular scanning region 12 ''' concentric circle with the minimum radius k. Since the encoder is designed as an optical encoder, the sensor is an optical linear sensor 17 used. As in 6 clearly recognizable, the linear sensor feels 17 the distance between four lines, ie four periods. The active area of the sensor is about 0.4 mm × 0.2 mm.

But it is also possible to produce the code disks according to the invention with the trained as described above spiral scale scale with larger diameters for larger optical encoder. The code discs then have an outer diameter in the range of about 30 mm to 500 mm and the width of the bars of the scale of the code disc is greater than 1 mm. So these code discs have coarser structures and can be made for example by injection molding. It is also conceivable to use structured plastic parts or stamped parts as code discs. The optical encoders with these code disks can be constructed discretely. The sensor used is preferably discrete photodiodes. These larger encoders are very cheap to manufacture. By using the code disc according to the invention with the neuentwickel The shape of the helical strokes following the equation given above achieves high signal accuracy.

It is also possible inductive encoder with the invention To equip code disks. So the code disc for an inductive encoder, for example, be designed so that she has very filigree structures. The outer diameter the code disc is then in a range of about 10 mm to 150 mm, the width of the bars of the scale of the code disk is in a range of about 0.1 to 3 mm. Such a code disc will used in highly integrated encoders.

7 shows an example of such a highly integrated inductive encoder 22 , The inductive encoder 22 again has a code disk 11 '''' with an annular scanning area 12 '''' on. In the scanning area 12 '''' are the spiral strokes 13 arranged here also as circle involutes to the inner circular edge of the scanning area 12 '''' are formed. The circle involutes 13 follow the equation already given. The encoder 22 is also circular in shape and has an opening in its center 21 on, by means of which he can be plugged onto a shaft. The inductive encoder 22 has 16 spiral strokes 13 on, the outside diameter of the code disk 11 '''' is 15.3 mm. This encoder is again designed so that the code disc or the scanning 12 '''' the code disc not to the center of the encoder 22 ie up to the opening 21 , extends. The distance between every two of the spiral lines 13 is preferably 1.2 mm. On the code disc 11 '''' is the position of the linear sensor 18 specified. The linear sensor 18 is again along a tangent to the inner circular edge of the scanning area 12 '''' aligned. The inductive encoder 22 is preferably formed as a mounted on the shaft of an inner rotor carrier with a glued printed circuit board (PCB).

For larger motors discretely constructed inductive encoders are used which have code disks with coarser structures. These code discs have an outer diameter in the range of about 30 mm to 500 mm. The spiral lines 13 The scale of these code discs have line widths of more than 3 mm and a maximum of about 30 mm.

Further it is also possible that inventively constructed Insert code disks in capacitive encoders. The code discs, which are used in capacitive encoder, also have one Outside diameter of about 10 to 140 mm. code discs with filigree structures with a line width of spiral Dashes in the range of 0.1 to 3 mm are for encoders used up to 60 mm in diameter. These encoders are for small Engines applied to the engine or to the Engine can be grown. Codewheiben with coarser Structures with line widths up to 50 mm are considered capacitive Encoder with a diameter up to 500 mm used. These encoders are suitable for larger engines and can also attached to the engines or installed in the engines become.

Advantageously, the spiral lines 13 of the scale of the code disk formed as a pseudo-random-cyclic code. In this way, with a single track, a code disc for an absolute encoder or an encoder with index can be realized. In addition, it can be provided that a type of modulation, for example amplitude modulation, phase modulation or pulse width modulation, is realized. It is also possible to modulate the track width, the track pitch or the intensity of the scale. An analog or digital modulation is possible. The code discs according to the invention can be produced in any way. For example, it is possible to produce a code disk in which electroformed metal is mounted on a dielectric. The code disk can also be produced by laser marking or by machining. Further manufacturing methods are PCB production, for example etching and photochemistry, or photolithography.

Preferably becomes an encoder with the code disk according to the invention in an electric motor to determine the position of the motor shaft used.

It can also be provided, an electric motor with the invention To equip code disc. The linear sensor is then external to the engine. This is especially hermetic in printers and motors completed housings relevant. The encoder is then open or externally realized.

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

• - US 5017776 [0007, 0035]

Claims (15)

Code disc ( 11 . 11 ' . 11 '' . 11 ''' . 11 '''' ) for an encoder with a circular scanning area ( 12 . 12 ''' . 12 '''' ) in which a scale of substantially helical, parallel lines ( 13 ), characterized in that the spiral-shaped lines ( 13 ) of the scale are designed such that they form an imaginary line ( 14 ) such that the in the intersections ( 15 ) to the spiral lines ( 13 ) created tangents ( 16 ) perpendicular to the imaginary line ( 14 ) and parallel to each other. Code disc according to claim 1, characterized in that the imaginary line ( 14 ) a circular tangent to a with the annular sensing area ( 12 . 12 ''' . 12 '''' ) concentric circle with the minimum radius k = at 2π where a is the distance between the bars ( 13 ) of the scale and n the number of strokes ( 13 ) of the scale. Code disc according to claim 1 or 2, characterized in that the spiral-shaped lines ( 13 ) of the scale according to the equation

are formed with k = at 2π . where a is the distance between the bars ( 13 ) of the scale and n the number of strokes ( 13 ) of the scale. Code disc according to one of claims 1 to 3, characterized in that the helical lines ( 13 ) of the scale are designed as a pseudo-random-cyclic code. Code disc according to one of claims 1 to 4, characterized in that the track width, the track pitch or the intensity of the scale is modulated. Encoder with a code disk ( 11 . 11 ' . 11 '' . 11 ''' . 11 '''' ) according to at least one of the preceding claims for mounting on a shaft and with a linear sensor for scanning the scale of the code disk ( 11 . 11 ' . 11 '' . 11 ''' . 11 '''' ). Encoder according to claim 6, characterized in that the linear sensor along the imaginary line ( 14 ) is aligned. Encoder according to Claim 6, characterized in that the linear sensor is slightly twisted with respect to the imaginary straight line ( 14 ) is arranged. Encoder according to one of claims 6 to 8, characterized in that the imaginary line ( 14 ) a circular tangent to a with the annular sensing area ( 12 . 12 ''' . 12 '''' ) concentric circle with the radius k = a a · n 2π where a is the distance between the bars ( 13 ) of the scale of the code disk and n the number of lines ( 13 ) of the scale. Optical encoder ( 19 ) according to one of claims 6 to 9, characterized in that the code disc ( 11 ''' ) has an outer diameter in the range of about 2 to 140 mm and the width of the lines ( 13 ) of the scale of the code disk is in a range of about 0.05 mm to 1 mm. Optical encoder according to one of the claims 6 to 9, characterized in that the code disc has an outer diameter from about 30 to 500 mm and the width of the bars of the scale the code disc is larger than 1 mm. Inductive encoder ( 22 ) according to one of claims 6 to 9, characterized in that the code disc ( 11 '''' ) has an outer diameter in a range of about 10 mm to 150 mm, and the width of the bars of the scale of the code disk is in a range of about 0.1 mm to 3 mm, preferably 1.2 mm. Inductive encoder according to one of the claims 6 to 9, characterized in that the outer diameter the code disc is in a range of about 30 mm to 500 mm and the width of the bars of the scale of the code disk is greater than 3 mm and maximum about 30 mm. Electric motor with a code disk according to a of claims 1 to 5. Electric motor with an encoder according to a of claims 6 to 13.