Method and rotary encoder for measuring the absolute angular position

The invention relates to a method for detecting an absolute angular position a rotatable component, in particular a shaft, wherein the first in a stationary unit comprising evaluation electronics at least two independent magnetoresistive sensor pairs by at least one magnetic field source are biased, the sensor pairs in the immediate Vicinity of the magnetic field source are arranged, and wherein in a second with the Component rotatable unit at least one modulator of the function of position the magnetic flux of the magnetic field source at the location of the sensor pairs in Density and / or direction changes, due to its rotation with the component, the Sensors covers periodically and affects their excitement, the Sensors are arranged one each sensor pair, such that it by the Covering elements of the modulator with an angle difference of a quarter overlap period are covered, as well as a digital encoder for Performing the method.

Drives for rotating machine components, especially shaft drives, with highly dynamic control behavior need for speed measurement State variables "rotor position" and "Speed". The number of control required data points is all the higher, the higher the dynamic behavior or the slower the speed of rotation of the rotating component or the shaft is. With the advent of high-precision technologies, which have place greater demands on the synchronism of waves grows a need to increasingly precise shaft drive controls. is the precision of the control depends on the resolution of the angle sensor and the speedometer, which provide the input to the drive control system available.

To measure from Bauteilwinkel- or shaft location Past developed many different technologies, this always with to determine higher precision, while there is a strong correlation between precision of the Shot and the precision of it to Measurement specific angle information.

To the precision of the measured absolute angle of a rotating component to increase, it is necessary, information from which the absolute Angular position can be determined on the rotating component in accordance with to further consolidate. The densification of discrete machine readable but angle information is a limit by the ambient conditions set, in which the angle information must be available, as For example, entry of operational flue dusts in the modulator-sensor housing. Although leaves the density with which the time discrete and independent Angle information can be applied to rotating components, enough room for even more precise absolute angle encoder as in the prior Technology, however, the components of which bear the angle information, or the reading method always sensitive, what a Demand for higher robustness precludes. Therefore, it is necessary to develop methods that allow angle accommodate more precise to can, with the robustness and reliability of the used case Components also expected to increase.

Example of robust and high-precision angle encoders are described in US Patent 4,039,936 and DE 19816696 A1. Characteristic of this as the closest prior art to be regarded technologies, it is, a magneto-resistive sensor to a static permanent magnet to assemble and this sensor as in the vicinity of a rotating ferromagnetic placing gear, which the rotating component on a Axis rotated so that the surface of the magneto-resistive sensor periodically obscured by the teeth of the rotating gear and released again becomes. Through the passing of a ferromagnetic tooth changes the magnetic flux density in the magneto-resistive sensor characterized its electrical resistance changes. The change in the electric Resistance of the magneto-resistive sensors is in the teachings to use these two documents, the passage of the border between determine tooth and gap. Both documents are difficulties describes the change in electrical resistance of the magnetoresistive Sensor through the arrangement of sensor, modulator and bias magnet to modulate so that the so-called zero crossing safely can be determined and precise. The zero crossing corresponds to the relative position of the sensor and the modulator, wherein the sensor from a Coverage passes through a tooth released by a gap. In the Difficulties the documents described are based on the observation that in the vicinity of the surface is one of magnetic field lines carrying ferromagnetic material and moreover reaching in the previously used in the prior art spatial area in the Near the modulator, in the sensors without loss of function can be used, inharmonious components where by the modulator periodically changing magnetic field occur that a Position detection of a passing modulator element difficult, or burdened with a higher uncertainty premium. As Solution is proposed in the document, the sensor itself so to Change that the effects of the above distortions by accommodation of coupled sensors at different positions relative to the Modulator are compensated and thus the detection of a zero crossing carried out precisely and in turn a square waveform with high temporal Edge precision for incremental or absolute positioning is available.

By doing so, although the zero crossing is very accurate be determined and thus also the angle of the component at the time of Zero crossing, but the resolution of the angular determination is the Number of passing teeth limited. To the resolution further increase, already the modulation of a sinusoidal signal has been proposed by which can determine the component position between two zero crossings, However, there are high demands on the quality, especially the asked harmonic poverty of the signal. To ensure the quality of the modulated Sinusoidal signal by a passing pulling ferromagnetic element to increase is proposed in the document DE 19521617, the magneto-resistive to curve conductor tracks on the chip surface, thereby also inharmonious components by density dislocations in the Edges of the tooth surface, which the modulated signal quality in the magneto-resistive can interfere with the sensor to reduce. In this document but proposed solution provides a fairly costly solution of Problem is to increase the accuracy of angle measurement.

Object of the invention is therefore to provide a method for robust and high-precision Measurement of the absolute angular position of a rotating component to at the disposal of the angle information on the component, which for Determination of the absolute angular position is required, a substantially having lower density than the angular resolution of the entire procedure equivalent.

Another object of the present invention is to provide a digital encoder for at the disposal of the by the proposed method, a signal Provides, from the absolute angular position with high accuracy can be determined, wherein the signal quality, which means harmonic poverty of the signal, the same should be good or better than in the prior art.

According to the invention, the object is different by a covering Sensor pairs with differing coverage period at Rotation of the component and determining the absolute angular position from the Comparison of excitation intensity of different pairs of sensors and the sensors each a sensor pair with each other dissolved, wherein the sensors GMR sensors are. Further advantageous embodiments result from the dependent claims.

This method enables a simple and inexpensive construction, and a cost-effective retrofitting of existing rotating components, especially shafts, because the component itself only with at least one simple modulator must be provided, wherein the at least one Modulator itself has no mechanical or electronic active components and having to have far fewer elements to sensor coverage needs, as an individual by this method absolute angular positions are determined. The separation into two units, in a first unit, which is stationarily arranged in the vicinity of the modulator and the electronic contains active components and a second unit, which have only one with a component, in particular a shaft co-rotating rigid component which is possible with comparatively little effort, if necessary, the exchange electronics of the angle encoder or by a more efficient replace electronics.

In contrast to methods in which the absolute angular position optically is taken up by reading a code, this method is suitable by modulation of an existing magnetic field for use in Areas where flue dusts, vapors and other precipitating Emissions are present, which the function of an optical method Shot interfere slightly or even completely can put out of action. The simple design of the modulator and the few in comparison to the Angular resolution required overlap elements is the entire procedure less sensitive to external interference.

Even compared to methods in which an incremental or absolute Angular position is taken up by means of a rotating pole wheel, has this method has the advantage that the rotating itself is not magnetized Unit is less sensitive to an external magnetic field, which interfere with a flywheel in its functionality or even completely destroy could, without the disturbance of the component, in particular the shaft, co-rotating unit with the naked eye can be detected. Because often positioned large machine components with the aid of magnetic grippers and / or assembled. In this assembly, the field strength of a magnet could in a magnetic pole wheel to be changed, with the result that the Receiving the magnetic field strength of the magnet wheel for Shot at would result in a falsified result and thus an incorrect measurement. In contrast, a ferromagnetic modulator are used, which can have a high coercive force, which is a measure of the Resistance of a material is in the presence of magnetic grippers to be magnetized without the use of the magnetic gripper an essential Shot deterioration would be expected.

The high and the necessary precision of the magnetic field modulation and sensor excitation is in the inventive method by the form of the modulator, its magnetic properties as well as the direction of the field magnetic flux at the location of sensors depends. The angular resolution the at least one modulator can be in comparison with the possible turn angular resolution of the method is comparatively low because the high Angular resolution by a combination of the relative position of different overlapping elements of at least one modulator to each other, and an electronic and / or digital electronic interpretation one using this method oberwellenarm modulated sinusoidal signal is achieved, which in synchronism with the frequency of Überdedeckung Sensors swings through the modulator.

Because, surprisingly, it was found that the modulation of improved sine signal in the magneto-resistive sensor by the means harmonics poorer, can be modulated when the sensor of a Magnetic field is biased, one for normal of the angle plate has oblique component, wherein a bias by a homogeneous magnetic field to an even higher harmonic of poverty modulated signal leads.

Likewise, it has surprisingly been found that such an arrangement of magneto-resistive sensor and preferred flow direction of the Bias magnet being used particularly low harmonic signals generated in the sensor plane normal and preferential direction parallel are aligned with each other.

Furthermore, it was surprisingly found that the modulator induced fluctuation of the magnetic flux density and direction at selected field intensity in the selected volume thus particularly can be set oberwellenarm by both the flux density of Bias, the distance of the space volume of the modulator, in where the sensors are located, and the material properties and by Geometry of the modulator particular skill, the magnetic flux to influence, to be coordinated. By this vote the can successive components a volume of space in the environment of operation of at least one modulator to be created in which inharmonious Components of the periodic changes in the magnetic flux density and - Direction are largely minimized. By varying and optimizing this Parameter, it is unnecessary, as proposed in the prior art changes made to the sensors, which allows, in a standardized and thus resorting lower cost sensor elements.

For the application of the method to have made the technology magnetic mass storage devices known GMR sensors as particularly Suitable highlighted the magnetic read heads as for the magnetic surfaces of hard disks written information serve. It has been found that the GMR sensors due to their Sensitivity interval particularly suitable for use in the invention Process for few harmonics modulation of a sinusoidal signal in a Angle encoder suitable. But there are also other magneto-resistive sensors in this method adjusting the ratio of magnetic field strength on Modulator distance, the spatial orientation and the geometric and / or material properties of at least one modulator usable.

As part of this document are magnetoresistive sensors understood such sensors using the Hall, MR, AMR, CMR, GMR and / or generally XMR effect an electrically usable signal from producing variations in a magnetic field.

Furthermore, it was found that by shaping of the sensors periodically covering elements of at least one modulator which Waveform can be further improved. Advantageously, is in Process for few harmonics modulating a ferromagnetic modulator used. Here, the parameters permeability and geometrical result Shape of the modulator material to minimize the distortion factor of the output signal.

It is likewise advantageous, the distance of the magnetoresistive sensors from the at least one modulator at selected magnetic flux density at least one magnetic field source to be dimensioned so that the magnetic field-sensitive Part of the magneto-resistive sensors is positioned such that this of the density and changes in direction of the magnetic flux at Rotation of the modulator is unaffected as a result of the discontinuous Transition from air to ferromagnetic material in the immediate undesired vicinity of the surface of the at least one modulator have inharmonious components. Although the severity of the Flux density and magnetic field in the sensor -richtungsänderungen of so less the farther the location of the sensor is removed from the modulator, however, impoverish the same discordant harmonic components with the distance. In an optimal distance from the modulators of discordant proportion of Magnetic flux and -richtungsschwingungen negligible and by the modulator induced amplitude change are still large enough to allow a magneto-resistive, especially GMR sensor, this with reasonable can be used for modulation accuracy of the electrical angle encoder signal.

Likewise, it has proved advantageous, different sensors with different modulation frequencies, which are preferably close to each other are to be energized in order for the vernier the angular position to determine between two zero crossings of the modulation frequency. By the use of different closely spaced modulation frequencies, the number of zero crossings in one revolution of the component or the shaft, the number of possible unambiguously identifiable Angular positions far below, it is possible, the angular position with a much higher precision to determine when it by counting and Identify individual zero crossings of a single modulation frequency is possible. The achievable in this way dividing the angle is in The range of the mathematical product of the number of zero crossings of the two modulation frequencies. This vernier, occasionally called "Vernierverfahren", the skilled artisan and the tool technology well known.

Preferably, in the method in each case two sensors of a Sensor pair shifted by a quarter of the coverage period with same period length and different pairs of sensors with different Period length covered, the different sensors couples Period lengths are covered, their difference a shorter coverage period length divided by the number of longer coverage periods is along an angular period of 2 π of the to be detected angle. The phase shift of a quarter of the coverage period of two sensors of a sensor pair is possible that the angular position between two zero crossings of the two phase-shifted can be clearly identified signals. By the above described Difference between the two modulation signals shifts the zero crossing of the two modulation frequencies to each other by a fraction of per coverage period the shorter coverage period to after a round of Component or the shaft by an angle of 2π, the zero crossing of the lower modulation frequency at the same time return to a zero crossing of the higher modulation frequency applies. At the modulation frequency difference described above there along one revolution of the component or the shaft only a single point at which the zero crossing of the lower Modulation frequency of the zero crossing of the higher modulation frequency applies. By comparing the angular information, the sensor pair a can be removed, with the angle information of the other sensor pair it is possible the overlap period to be determined unambiguously.

To carry out the process of the invention, an angle encoder is used to Detecting the absolute angular position of a rotatable component, in particular a shaft, consisting of a first stationary unit comprising a having evaluation electronics in which at least two independent magnetoresistive Sensor pairs biased by at least one magnetic field source are, the sensor pairs in the immediate vicinity of the magnetic field source are disposed and wherein in a second rotatable with the component unit at least one modulator of the function of position of the magnetic flux Magnetic field source at the location of the sensor pairs in density and / or direction changed, as a result of its rotation with the component, the sensors periodically covers and their excitement influenced, said sensors each one are sensor pair arranged so that on the one with a phase shift quarterly coverage period be masked, used.

Advantageously, there is at least one magnetic field source consists of a Permanent magnets and / or electromagnets, wherein in particular Advantageously, the magnetization direction of the magnet obliquely to Surface of the magnet is arranged. In the optimization of the output signal of the angle sensor, it has been found that the magneto-resistive Sensors best by an obliquely magnetized permanent magnetic foil be biased. This ensures that the various sensors according to the manufacturing tolerance in the Manufacture of permanent magnet film with a uniform, homogeneous biased and the same height as rectified magnetization will.

In an arrangement of magneto-resistive sensors is an arrangement advantageous to produce a few harmonics signal used in the Preferential flow direction of the magnet used for biasing and the sensor plane normal of at least one modulator parallel to each other.

There are also other not specifically named here command and direction combinations usable by the vote each other very few harmonics signals lead, for example, an oblique arrangement of Sensor level to the preferred direction of the bias used to Magnet.

For advantageous bias of GMR sensors in the case of oblique Arrangement of the preferred direction of the Vormagnetisierungsmagnetfeldes Sensor surface, the angle of preferably used obliquely magnetized permanent magnet sheet or obliquely magnetized Permanent magnet and / or electromagnet 5 ° - 85 ° to the normal of the Level of each sensor, particularly advantageously about 45 ° to the Normal of the plane of each sensor.

The oblique bias the magnetoresistive sensors held in a linear operating range, which means that the output signal is harmonic poorer with the fluctuation of the magnetic field. By a parallel alignment of the sensor surface with the plane of the co-rotating Modulator and the slanted bias of the sensor to meet the Magnetic field lines obliquely on to the surface of the modulator. By periodic coverage and enable the sensors by the modulator the magnetic field changes in the sensor, both in direction and in the density the magnetic flux. The fact that the plane of rotation of the modulator obliquely is aligned with the direction of magnetic flux, arises between Bias magnet and a modulator volume of magnetic Flow, in which the density changes and the changes in direction comprise mainly harmonic components and their inharmonious Components are negligible.

In the case of the parallel to the sensor plane bias performs Magnetfeldsensitivierungsschicht which usually on the surfaces magneto-resistive sensors is mounted to a bias of the Sensor. This thus generated bias also means that the leads Sensor is maintained at an optimum linear working range, leading to Signals with a low distortion rate, equivalent to a small Harmonic component having leads.

In the event that the magnetic field source is a permanent magnet or an obliquely or perpendicularly magnetized permanent magnet film, it has proven advantageous proved, when the magnet or the magnetic particles of the magnetized Permanent magnet film AlNiCo, sintering or rare earth magnets are.

To produce a volume of space in the vicinity of the modulator, in that with the Covering the magnetic field strength, so the magnetic flux, or the Direction of magnetic flux in almost exclusively harmonious swinging way, it has proved advantageous if the field strength at Location of the unmodulated sensor 1 mT to 300 mT, preferably about 15 mT is.

Regardless of the arrangement of the sensor of the magnets and of the modulator it may be the sensors are Hall sensors, MR, AMR, CMR, GMRoder generally act XMR sensors, particularly preferably in the Angle encoder according to the invention, however, GMR sensors.

For further optimization of a few harmonics of the output signal Angle sensor, it has proved to be particularly advantageous if the Sensors are placed directly on the at least one magnetic field source. To arrange a magneto-resistive sensor on a magnet, it can in accordance with the above advantageous embodiments a eccentrically an axial symmetry on the pole face in the axial direction magnetized bar magnets arranged sensor act. Especially advantageously has proved, if the sensors directly to the Surface of an obliquely magnetized magnets are applied. Particularly good results were obtained when the sensors together on an obliquely magnetized permanent magnetic foil were applied, pass the permanent magnet film of a coherent piece can, on which are arranged the sensors. In selecting the above-mentioned Parameters, it has proven to be advantageous and it has to be particularly out few harmonics output signals when the sensors in a Range of 100 microns - 5 mm, but more preferably from 500 microns 1.5 mm are mounted remotely from the at least one modulator.

In the arrangement of vertically-mounted sensors whose sensor surfaces perpendicular to the passing modulator overlapping elements are arranged, it has proved to be advantageous if the sensors arranged vertically on a perpendicular magnetized permanent magnetic foil be or to a vertical section and perpendicularly magnetized Bar magnets are placed.

Wherein the at least one modulator may be two or even more ferromagnetic coaxially arranged to the axis of the angle to be detected Gears act with helical and / or Planradverzahnung. In the case a gear with spur teeth are the magneto-resistive sensors arranged parallel to the gear level close to the ring gear, said preferably alternately releasing individual teeth of the gear, the sensors and cover again. However, it is also possible for the sensors in parallel to arranging tangent to the end surface, so that upon rotation of the ferromagnetic Each gear tooth per one a magneto-resistive sensor periodically comes close and moves away from it again. In a Planradverzahnung the magneto-resistive sensors preferably parallel to the plane of the Gear mounted, but can also tangential to planradverzahnten be arranged gear.

To achieve the different modulation frequencies for different Pairs of sensors, it has proved to be advantageous if the at least one Modulator from a group of three coaxial gearwheels, wherein the Gears 64, have 63 and 56 teeth. By comparing the sensor signals, which are generated by the gear with 64 teeth, with the Signals generated by the sensor pair on the gear with 63 teeth are a unique angular resolution is already possible with the Comparison of the zero-crossing position of the sensors an individual coverage period identified, and wherein the signals from the sensor pairs, in where the two sensors of one with a phase shift of one quarter Coverage period are energized, and the angular position within the Coverage period can be determined.

However, the number of the teeth can freely on the different modulators be chosen as long as from the fact a component rotation resulting movements of the zero crossings of individual teeth clearly a can be derived angular position.

The additional gear and the additional sensor pair, which 56 times passes through an overlap period during a revolution, is an additional redundant signal yet that a through evaluation confirms determined position or negated this. In many industrial applications must be expected that the signals by strong electromagnetic pulses, for example by launching Machine or by sudden electrical switching operations, to be disturbed. Furthermore, it is by the use of a redundant signal possible the angular resolution, which is in use without redundant Signals by temperature and aging-related drift of the used Sensors could deteriorate to maintain.

In addition to the gear wheels, it is also possible for a modulator of a to construct the ferromagnetic disc, the disc radial slots, has grooves or other. The function of the sensors covering and re-releasing the teeth of the aforementioned toothed wheel assume here the radial slots, grooves or other. at Use of a disk, it is possible by variations in the plate thickness, which lies in the range 1 mm to 0.1 mm, and thus the Level of ability, the magnetic field of the bias magnet to BE influence the amplitude of the magnetic field vibration during rotation of the catching modulator. This results in a further optimization parameters to the creation of a volume of space in which the magnetic Flux density both in magnitude and in direction with the modulation frequency swings. Even with the use of the ferromagnetic radial slots, grooves or having disc has it proved to be advantageous if the disc three concentric rings of having equidistantly arranged slots, wherein the rings of 64, 63 and 56 slots are made and the angle information as explained above, determined will.

In the method according to the invention it is not necessary that the Modulator is moved. Each angle information is also in the rest position Modulator from the corresponding sensor signals derived.

The invention is explained in more detail with reference to FIGS.

It shows<dl tsize="6"><dt>Fig. 1</dt><dd>arranged a section of a centered at the end of a shaft Angle encoder with axial section through angle transmitter, Shaft bearing and shaft,</dd><dt>FIG. 2</dt><dd>the plan view of a shaft encoder disk and</dd><dt>Fig. 3</dt><dd>two oscillator charts a single modulated magneto-resistive sensor, wherein the sensor in the individual Charts was biased differently.</dd></dl>

1 shows a longitudinal section of a successive arrangement of Inventive angle sensor 1, a bearing housing 2 and a shaft. 3 The angle sensor 1 is composed of two units, the first unit on a Mounting plate 4 has a transmitter 5, which on a first side the first unit is fixed and three magneto-resistive sensor pairs, 6, 7 and 8, on a not illustrated here permanent magnet film of a second to the modulator / disk 9 facing side of the first unit are arranged. The first unit is a not in the figure by means shown housing to the bearing housing 2 is fixed. The modulator / disk 9 is disposed on the top surface of the shaft 3 with a fastening element 10 and is fixed to the shaft. The shaft 3 is in a double bearing stored 11 which is received in the bearing housing the second In rotation the shaft 3, the modulator 9 rotates with it and changed the magnetic Flow at the location of sensor pairs 6, 7 and 8 by periodic coverage and Release.

Figure 2 shows the modulator disc 9 in a plan view. Clearly visible are three concentric rings with regular radially arranged trapezoidal Slots 12, 13 and 14, which the magneto-resistive sensors periodically cover. The outermost ring of radial slots 12 has 64 Slots, the middle ring of radial slots 13 has 56 slots and the innermost ring of radial slots 14 has 63 slots. The centric receiving bore 15 with a variable internal diameter, depending on bemessender to shaft 3 for attachment to the diameter of the shaft 3 be adjusted.

Figure 3 shows a diagram of the waveform of a magneto-resistive Sensor at different selected magnetization direction. The optimized Waveform 16 shows a symmetrical periodic sinusoidal curve over several periods, from which the angle information by measuring the Amplitude at any one time can be determined. contrary, since the waveform 17 of the sensor that deviates from the optimum with a Magnetization direction has been biased, significant asymmetries equivalent high THD comprising, on. In the diagram, has the waveform 16 a nearly ideal sinusoidal curve on, however, is the waveform of the signal 17 clearly in the positive half-waves compared to the ideal sinusoidal shape distorted, which is not synonymous with a negligible harmonic content or a high THD is.

While the present invention with reference to the previous been described and illustrated preferred embodiment, it is for the Skilled in the art obvious that changes in the form and details are possible without departing from the scope of the invention as defined in the is defined the following claims.

When in this document MR sensors or magneto-resistive sensors be taught, so therefore are the technologies MR, AMR, GMR, TMR, CMR, reverb and generally XMR sensors equally meant.

Similarly, the frequency ratios of the modulators or modulator sections selectable in any other relationship, provided that from a unique angular position can be determined.

Under an overlap period is in accordance with the inventive teaching the angle meant the modulator between the beginning of a sensor coverage by a cover element of the modulator, subsequently the sensor coverage itself, the beginning of the re-release, the Once released and until the next start of a next sensor coverage by an adjacent tooth, or a neighboring Coverage item, passes. The number of overlapping periods per Sensor, which overlapped by the at least one modulator and is free again given corresponds along a complete component round Registered exactly the number of overlapping elements used for sensor coverage of the modulator.

Those skilled in the art will appreciate that for identifying the angular position of the Component is a number from 0 to 2 is given π, wherein the position of the Component π coincides in position 0 to the position 2, with the difference that the component or the so-coupled modulator at a Revolution has made of 2 π a complete revolution. A distinction of the component or modulator circulation, according to the above explained angular relationship of a component or modulator round π from one period 0 to 2, which does not refer to a component circulation, but the angle crossing of along a coverage period according to the above definition. In both definitions behaves Angle, is what to 2 indicated normalized π in the dimension of 0, linear proportional to the actual distance angle of the component or the coupled modulator.

The coverage period may in the inventive process and in the angle sensor according to the invention, a ratio of overlap length have to re-release length, which is less than 1, equal to 1 or greater than 1, being under the overlapping length of the angle is meant which the component or the modulator can pass through, without the sensor is again freely given and in accordance with the re-release of the length Angle, which are traversed by the component or modulator can, without the sensor is covered. The sum of overlap length and re-released in length corresponds to the coverage period. This means that the pulse-pause ratio, often duty or Duty Cycle called, in the process is freely selectable and can optimize a few harmonics signal can be varied.

The sensor coverage in the method of continuously covered again freely given change. A binary change from coverage to re-release this means an extreme position in the parameter optimization as a continuous smooth transition from covers again freely given. In any case, is the coverage period length by corresponding angular positions according to the above Definition clearly defined.

LIST OF REFERENCE NUMBERS

<dl tsize="2" compact="compact"><dt>1</dt><dd>angle encoder</dd><dt>2</dt><dd>bearing housing</dd><dt>3</dt><dd>wave</dd><dt>4</dt><dd>mounting plate</dd><dt>5</dt><dd>evaluation</dd><dt>6</dt><dd>magnetoresistive sensor pair</dd><dt>7</dt><dd>magnetoresistive sensor pair</dd><dt>8th</dt><dd>magnetoresistive sensor pair</dd><dt>9</dt><dd>Modulator / disc</dd><dt>10</dt><dd>fastener</dd><dt>11</dt><dd>double bearings</dd><dt>12</dt><dd>Ring of radial slots</dd><dt>13</dt><dd>Ring of radial slots</dd><dt>14</dt><dd>Ring of radial slots</dd><dt>15</dt><dd>Aufnahmebohrung</dd><dt>16</dt><dd>optimized waveform</dd><dt>17</dt><dd>not optimized waveform</dd></dl>