Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
  • G01D5/204—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils
  • G01D5/2053—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils by a movable non-ferromagnetic conductive element
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/244—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains
  • G01D5/245—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing characteristics of pulses or pulse trains; generating pulses or pulse trains using a variable number of pulses in a train
  • G01D5/2454—Encoders incorporating incremental and absolute signals
  • G01D5/2455—Encoders incorporating incremental and absolute signals with incremental and absolute tracks on the same encoder
  • G01D5/2457—Incremental encoders having reference marks

Definitions

• the invention relates to an inductive rotation angle sensor for determining relative angular positions according to the preamble of claim 1 and to a method for operating an inductive rotation angle sensor according to claim 8.
• Inductive rotation angle sensors are used for example in encoders for determining the angular position of two relatively rotatable machine parts.
• excitation coils and receiver coils are applied approximately in the form of interconnects on a common circuit board, which is firmly connected, for example, with a stator of a rotary encoder.
• this printed circuit board there is another circuit board, which is not infrequently designed as a partial disk on which alternating electrically conductive and non-conductive surfaces are applied as a division or division structure at periodic intervals, and which is non-rotatably connected to the rotor of the rotary encoder.
• Rotary encoders with inductive rotation angle sensors are frequently used as measuring devices for electric drives, for determining the absolute angular position of corresponding drive shafts.
• the invention is therefore based on the object to provide a cost-effective inductive rotation angle sensor and a method for Berieb such a rotation angle sensor, by which / which a high signal quality and extremely accurate measurement results can be achieved.
• the inductive rotation angle sensor a printed circuit board, on which an exciter track and a first, second and a third receiver track are applied.
• the rotation angle sensor comprises a dividing element, which is rotatable relative to the printed circuit board and comprises a first and a second graduation track, each consisting in particular of alternately arranged, electrically conductive and nonconductive graduation regions.
• the first and second graduation tracks and the first and second receiver tracks are configured so that within a revolution of the dividing element relative to the printed circuit board, signals having a first period number can be generated by the first receiver track and signals having a second period number can be generated by the second receiver track.
• the dividing element on a third pitch track which may also consist of alternately arranged, electrically conductive and non-conductive division regions, wherein the third divisional track and the third 270leiterbahn are configured so that within a revolution of the dividing element relative to the circuit board through the third 270leiterbahn signals with the first period number can be generated.
• a rotation angle sensor is in particular suitable for reducing measurement errors due to wobbling movements or skewing of the partitioning element relative to the printed circuit board.
• the influence of a skewing of the stator can be reduced.
• the distance of the first pitch track to the axis of rotation differs from the distance of the third pitch track to the axis of rotation.
• the first graduation track has a radius of curvature that is different from the radius of curvature of the third graduation track.
• the innermost graduation track is applied in a region which is bounded by a smaller radius r towards the rotating pocket.
• the outermost graduation track is within a larger radius R, both radii r, R have their origin in the axis of rotation.
• the invention is particularly advantageous in conjunction with annular dividing disks which have a comparatively large inner bore. With this specification, the smaller radius r is often comparatively large. In particular, therefore, the invention is advantageously usable when the ratio of the larger radius R to the smaller radius r is smaller than 3/2 (R / r ⁇ 3/2).
• the angle of rotation sensor in particular the printed circuit board, comprises a means by which the signals of the third receiver track can be combined with the signals of the first receiver track to form a total signal, whereby a relative angular position between the printed circuit board and the graduation element is reduced from the overall signal. and cultivation tolerances, is determinable.
• the means may for example be designed as an electronic circuit and be designed in particular as an analog electronic circuit.
• the means is an addition or subtraction means, or an addition or subtraction circuit.
• the circuit can only mean a serial or a parallel interconnection of the first and the third receiver conductor track.
• period number is to be understood as the number of signal periods which are generated within one revolution of the dividing element or the dividing disk relative to the printed circuit board by a receiver printed conductor.
• the first period number is smaller than the second period number, in particular, the first period number can assume the value one.
• the first period number is odd and the second period number is even.
• the signals producible by the first receiver trace may have a phase offset of 3607 (2-n1) from the signals that can be generated by the third receiver trace, where n1 represents the value of the first period number of the signals of the first and third receiver traces.
• the printed circuit board has a first receiver track and a third receiver track, wherein the first receiver track comprises two first receiver tracks and the third receiver track comprises two third receiver tracks.
• the invention comprises a method for operating a Drehwin- kelsensors, wherein the rotation angle sensor comprises a printed circuit board on which an exciter track and a first, second and third receiver track are applied. Furthermore, the rotation angle sensor has a dividing element which is rotated relative to the printed circuit board during operation and comprises first, second and third graduation tracks, the graduation tracks each consisting in particular of alternately arranged, electrically conductive and nonconductive graduation regions.
• the first, second and third graduation tracks and the first, second and third receiver tracks are configured to generate signals having a first period number and the second receiver track signals having a second period number within one revolution of the divider element relative to the circuit board through the first and third receiver tracks ,
• the signals with the first Period number are combined into a total signal and from the total signal, the relative angular position between the circuit board and the dividing element is determined or generates information about the relative angular position.
• the signals of the first period number are combined into a total signal using an addition or subtraction operation.
• the circuit board has a first receiver track and a third receiver track, wherein the first receiver track comprises two first receiver tracks and the third receiver track comprises two third receiver tracks, so that two total signals can be generated.
• the two total signals have a phase offset of 90 °.
• the rotation angle sensor can also be designed so that more than two total signals can be generated, for example three, which then each have a phase offset of 120 ° or 60 ° to each other.
• FIG. 1 shows a plan view of a dividing disk, according to a first embodiment
• FIG. 2 shows a plan view of a printed circuit board according to the first exemplary embodiment
• FIG. 3 shows a plan view of a dividing disk, according to a second exemplary embodiment
• FIG. 4 shows a plan view of a printed circuit board according to the second exemplary embodiment
• FIG. 5 shows a plan view of a dividing disk, according to a third exemplary embodiment
• FIG. 6 shows a plan view of a dividing disk, according to a fourth exemplary embodiment
• FIG. 7 a shows a profile of the signals generated by the receiver tracks of the first receiver track.
• FIG. 7b shows a profile of the signals generated by the receiver tracks of the third receiver track.
• FIG. 7c shows a course of the total signals
• Figure 8 is a sectional view of a rotary encoder.
• Figures 1 - 6 show a total of four embodiments of a rotation angle sensor according to the invention.
• FIG. 1 shows a dividing element in the form of an annular dividing disk 2 according to a first exemplary embodiment.
• the partial disk 2 consists of a substrate 2.4, which is made in the embodiments of epoxy resin, and on which three graduation tracks 2.1, 2.2,
• the graduation tracks 2.1, 2.2, 2.3 are arranged.
• the graduation tracks 2.1, 2.2, 2.3 are of circular design and are arranged on the substrate 2.4 concentrically with respect to an axis of rotation A with different diameters or radially offset from one another.
• the graduation tracks 2.1, 2.2, 2.3 each consist of a periodic sequence of alternately arranged electrically conductive graduation regions 2.1 1, 2.21, 2.31 and nonconductive graduation regions 2.12, 2.22, 2.32.
• the substrate 2.4 was not coated.
• the two inner graduation tracks 2.1 and 2.3 respectively the first and the third graduation track 2.1 and 2.3, in the illustrated embodiment in each case from a first semicircular graduation area 2.11, 2.31 with electrically conductive material, here Copper, and in each case a second semicircular division region 2.12, 2.32 in which no conductive material is arranged.
• the innermost graduation track 2.1 is applied in a region which is limited to the rotary ash A through the radius r.
• the second graduation track 2.2 lies on the substrate 2.4, the second graduation track 2.2 also consisting of a multiplicity of electrically conductive graduation areas 2.21 and non-conductive graduation areas 2.22 arranged therebetween.
• the different division regions 2.21, 2.22 are materially formed here as well as the division regions 2.11, 2.12 of the first and third division tracks 2.1, 2.3.
• the second graduation track 2.2 in the exemplary embodiments illustrated comprises thirty-two periodically arranged, electrically conductive graduation regions 2.21 and correspondingly thirty-two non-conductive graduation regions 2.22 arranged therebetween.
• the second graduation track 2.2 lies within the radius R, wherein the radius R has its origin in the axis of rotation A.
• the annular dividing disk 2 or the substrate 2.4 has a comparatively large inner bore for receiving a shaft 4 to be measured (FIG. 8). Accordingly, the ratio R / r is relatively small and is here about 1.34.
• the printed circuit board 1 shown in FIG. 2 for scanning the indexing disk 2 according to FIG. 1 comprises two receiver printed conductors 1.11, 1.12 as receiver coils in an innermost receiver track 1.1, an additional two receiver printed conductors 1.31, 1.32 in a middle receiver track 1.3 and an additional one in the outermost receiver track 1.2 Pair of receiver tracks 1.21, 1.22.
• the associated pairs of receiver traces 1.1 1, 1.12; 1.21, 1.22; 1.31, 1.32 of a respective receiver track 1.1, 1.2, 1.3 are in this case arranged offset relative to each other.
• 1 exciter tracks 1.4 are provided as excitation coils on the circuit board, which are applied to an inner, a middle and an outer exciter track.
• the circuit board 1 itself has a central bore 1.5 and is designed as a multilayer printed circuit board.
• the dividing disc 2 and the circuit board 1 face each other, so that the axis of rotation A passes through the centers of both elements and at a relative rotation between part plate 2 and circuit board 1 in the circuit board 1 dependent on the respective rotational position angle information by induction effects can be generated. It is unavoidable that the dividing disk 2 relative to the circuit board 1 during the rotational movement also performs wobbling movements, which are caused by manufacturing or cultivation tolerances.
• the exciter printed conductors 1.4 generate a time-varying electromagnetic excitation field in the area of the receiver tracks 1.1, 1.2, 1.3 or in the area of the graduated tracks 2.1, 2.2, 2.3 scanned therewith.
• the exciter printed conductors 1.4 are formed as a plurality of planar-parallel current-carrying individual printed conductors. If the exciter printed conductors 1.4 of a conductor track unit are all flowed through by current in the same direction, then a tubular or cylindrically oriented electromagnetic field is formed around the respective printed conductor unit. The field lines of the resulting electromagnetic field run in the form of concentric circles around the conductor track units, the direction of the field lines depending in a known manner on the current direction in the conductor track units.
• the current direction of the conductor track units immediately adjacent to a common receiver track 1.1, 1.2, 1.3 or the corresponding shading of these track track units is to be chosen opposite, so that the field lines in the area of the receiver tracks 1.1, 1.2, 1.3 are each oriented identically.
• the supply of the exciter tracks 1.4 with A time-varying supply voltage is provided by supply voltage taps.
• the respective course of the signals S1.11, S1.12 deviates in reality from the ideal phase offset and from an ideal sinusoidal shape due to tolerance-related wobbling movements and inclinations. Furthermore, the signals S1.11, S1.12 have an offset relative to one another.
• the signals S1.31, S1.32 deviations from an ideal sinusoidal shape as well as a non-ideal phase offset and an offset error can also be identified according to FIG. 7b.
• the phase offset between associated receiver tracks 1.1 1, 1.31; 1.12, 1.32 corresponds to the formula 3607 (2-n1), so that therefore the receiver conductor 1.1 1 to the receiver conductor 1.31 is arranged 180 ° out of phase, as well as the receiver conductor 1.12 to the receiver conductor 1.32.
• the signals S1.1 1, S1.12, S1.31, S1.32 are then combined or interconnected with one another such that overall signals S1, S2 according to FIG. 7c are obtained. In the present case, the signals S1.11, S1.12 S1.31, S1.32 are subjected to an analogue subtraction.
• the total signals S1, S2 are then demodulated by means of an evaluation in a subsequent step. From the scanning of the graduation tracks 2.1, 2.3 thus results in a relatively coarse, absolute position information within a revolution of the disc 2 about the axis of rotation A.
• the total signals S1, S2 provide a unique absolute position signal within a revolution of a shaft 4 (see Figure 5), regardless Toggle movements and / or misalignment of the index plate 2 or the printed circuit board 1.
• On the known evaluation of 90 ° out of phase total signals S1, S2 direction detection is also ensured in the rotational movement.
• an absolute angular position with the accuracy of the second receiver track 1.2 is formed by means of a suitable algorithm. This is achieved in conjunction with the coarse absolute angular position determination via the first and third graduation tracks 2.1, 2.3.
• the invention is particularly advantageous when signals S1.11, S1.12 S1.31, S1.32 having a low period number n1 are combined with signals S1.21, S1.22 having a high period number n2 ,
• the first graduation track 2.1 can also be arranged radially outside the second graduation track 2.2.
• the first receiver track 1.1 also lies radially outside the second receiver track 1.2, while the third graduation track 2.3 and third receiver track 1.3 lie radially all the way inside.
• Embodiments one and two are now the division Traces 2.1 'and 2.3' designed so that the electrically conductive graduation areas 2.1 1 ', 2.31' are not applied to the substrate 2.4 on the entire surface, but only in the form of a circumferential conductive strip.
• This embodiment has the particular advantage that the eddy currents generated in the division regions 2.1 1 ', 2.31' flow in a directionally defined manner. For the generation of corresponding signals, the currents with radial direction component have a decisive influence. Due to the strictly radially aligned strip regions of the conductive graduation regions 2.1 1 ', 2.31' flows inevitably flow in this direction.
• the associated printed circuit boards for the third and fourth embodiments are not shown in the figures, because they do not differ in principle from the printed circuit boards 1 of the first and second embodiments.
• the third and the fourth embodiment are characterized by an extremely efficient design of the division tracks 2.1 ', 2.3' and the rotation angle sensor.
• the geometric configurations of the second and fourth embodiments have the advantage that the first and the third receiver track 1.1, 1.3 have a comparatively large radial distance. This has the effect that the reduction of the negative influence of manufacturing or cultivation tolerances on the measurement result is particularly effective reach.
• FIG. 8 shows a rotary encoder which is equipped with the inductive rotation angle sensor according to the invention.
• the rotary encoder has a fixed housing 3 and the shaft 4 rotatable relative to the housing.
• the shaft 4 serves to receive a rotatable machine part, for example a motor shaft whose angular position ⁇ is to be determined.
• the part plate 2 is fixed against rotation.
• the circuit board 1 is attached to the housing 3. Due to the fact that the annular dividing disk 2 can receive the shaft 4, the dividing disk 2 has a comparatively large inner bore for receiving the shaft 4 to be measured.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Transmission And Conversion Of Sensor Element Output (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

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Publications (1)

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ID=40688311

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• 2008
  • 2008-04-09 DE DE102008017857A patent/DE102008017857A1/de not_active Withdrawn
• 2009
  • 2009-03-24 WO PCT/EP2009/053427 patent/WO2009124836A1/de not_active Ceased
  • 2009-03-24 EP EP09730838.1A patent/EP2265902B1/de active Active
  • 2009-03-24 US US12/935,218 patent/US8278911B2/en active Active
  • 2009-03-24 JP JP2011503396A patent/JP5314125B2/ja active Active
  • 2009-03-24 CN CN200980113191XA patent/CN101990628B/zh active Active

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