EP1756525A1 - Measuring device for measuring magnetic angles and/ or paths - Google Patents

Measuring device for measuring magnetic angles and/ or paths

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Publication number
EP1756525A1
EP1756525A1 EP05749254A EP05749254A EP1756525A1 EP 1756525 A1 EP1756525 A1 EP 1756525A1 EP 05749254 A EP05749254 A EP 05749254A EP 05749254 A EP05749254 A EP 05749254A EP 1756525 A1 EP1756525 A1 EP 1756525A1
Authority
EP
European Patent Office
Prior art keywords
magnetic field
measuring device
angle
sensor
pin magnets
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP05749254A
Other languages
German (de)
French (fr)
Inventor
Frank Bürger
Karin Wittkamp
Waldemar Stephan
Christoph Pfeiffer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pierburg GmbH
Original Assignee
Pierburg GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Pierburg GmbH filed Critical Pierburg GmbH
Publication of EP1756525A1 publication Critical patent/EP1756525A1/en
Withdrawn legal-status Critical Current

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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
    • G01D5/142—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 using Hall-effect devices
    • G01D5/145—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 using Hall-effect devices influenced by the relative movement between the Hall device and magnetic fields

Definitions

  • the invention relates to a measuring device for angle and / or displacement measurement.
  • the invention relates to a measuring device for angle and / or displacement measurement for actuating elements in motor vehicles.
  • the angle measurement is necessary in motor vehicle elements, for example for controlling throttle or exhaust flaps.
  • the position of the flap must be determined exactly.
  • a device for determining the angle of rotation ie the opening angle of a throttle valve, is known from DE 199 03 490.
  • the throttle valve is connected to a pivot axis and, via several intermediate elements, to a ring magnet arranged concentrically to the pivot axis.
  • the ring magnet is rotated when the throttle valve is swiveled.
  • Two magnetic field sensors such as Hall sensors, are arranged in the housing cover. The two sensors are offset from one another outside the ring magnet by 180 ° arranged. Two angle-dependent signals are generated by the two sensors.
  • the field development curves generated by the two sensors are essentially sinusoidal, the curves being essentially linear in an angular range of ⁇ 45 °.
  • the provision of a ring magnet with two sensors arranged outside the ring magnet requires a large installation space. This is disadvantageous, in particular, when determining the angle of rotation of throttle and exhaust gas flaps, since these are arranged in an area of the engine in which there is little space.
  • the object of the invention is to provide a measuring device for angle and / or displacement measurement, which requires a small installation space and can be produced inexpensively.
  • the measuring device for angle and / or displacement measurement which is particularly suitable for actuating elements in motor vehicles, has a moving element, such as a gearwheel or a slide.
  • a magnetic field generator is connected to the movement element.
  • a magnetic field sensor is assigned to the magnetic field generator, which detects the magnetic field generated by the magnetic field generator or generates signals as a function of the detected magnetic field.
  • the magnetic field changes due to the relative movement between the magnetic field generator and the magnetic field sensor, a signal being generated as a function of the change in the magnetic field.
  • the signal generated by the magnetic field sensor is transmitted to an evaluation device.
  • the evaluation device can, for example, be part of an evaluation and / or control electronics, the control electronics, for example, controlling the motor vehicle control element.
  • the magnetic field generator has at least two pin magnets arranged at a distance from one another.
  • the at least two Pen magnets are, for example, on a swiveling one
  • the pin magnets can be arranged on a displaceable movement element, such as a carriage, at a linear distance from one another.
  • a magnetic field is generated by the two pin magnets arranged at a distance from one another, the magnetic field strength changing depending on the position of the pin magnets relative to the magnetic field sensor. In this way, the position of the movement element can be determined.
  • the sensor knows the curve of the magnetic field as a function of the position of the pin magnets or is stored in the evaluation unit, so that the position of the movement element can be derived from this.
  • the pin magnets are preferably selected, in particular with regard to their size and magnetic strength, in such a way that there is a quasi-linear magnetic field between the two pin magnets in the range of motion of interest. This has the advantage that it is not necessary to store or determine the magnetic field curve, and thus a simply constructed magnetic field sensor and a correspondingly simply constructed evaluation unit can be used.
  • pin magnets has the advantage that these are small components and the circular, in particular diametrically magnetized magnets known from the prior art can be omitted.
  • the measuring device according to the invention thus requires only a small installation space and can be produced very inexpensively.
  • the magnetic field sensor is preferably a Hall sensor, in particular a Hall sensor that can be programmed as a support point. With the help of Hall sensors, the magnetic field can be detected precisely.
  • the pin magnets are preferably oriented such that their i ⁇ lord-south orientation is essentially perpendicular to the direction of movement. This ensures that the magnetic field between the two pin magnets can be detected well by the magnetic field sensor.
  • a particularly preferred embodiment of the measuring device is a device for detecting the angle of rotation for throttle and / or exhaust gas flaps in motor vehicles.
  • a pivot axis which is preferably connected directly to the flap, is provided.
  • the magnetic field generator in the form of at least two pin magnets is arranged at a distance from the center line of the swivel axis.
  • the two pin magnets are preferably arranged on a circular line.
  • the magnetic field sensor is arranged adjacent to the pin magnets or to the magnetic field generated by the pin magnets.
  • the magnetic field sensor is arranged at such an, in particular axial, distance from the magnetic field generators that the magnetic field lines of the two magnetic field generators have a smooth transition from one another in the region of the magnetic field sensor.
  • This preferred arrangement according to the invention is based on the knowledge that the field lines are at a small distance from one another in one very acute angles to each other, ie do not form a smooth transition. As the axial distance increases, the transition between the field lines becomes smoother, but as the distance increases, the field strength decreases. Depending on the magnetic field strength generated by the magnet, an optimal distance can be determined at which the magnetic field strength is still sufficient, in particular also depending on the sensitivity of the magnetic field sensor, and thus the smoothest possible transition of the magnetic field lines is given.
  • the smooth transition is, in particular, an angle between the intersecting magnetic field lines of the two magnetic fields of more than 60 °, in particular more than 90 ° and particularly preferably more than 120 °. It must be taken into account here that the magnetic fields generated by the two magnetic field generators depend on the external dimensions, in particular the diameter of the magnetic field generators, on the material and on their axial extension.
  • the optimal position of the magnetic field sensor in relation to the magnetic field generators can be determined by experiments.
  • the magnetic field sensor is arranged in such a way that there is an essentially linear profile of the magnetic field line in the angle region of interest.
  • FIG. 1 a schematic top view of an angle measuring device
  • FIG. 2 a schematic side view along the line II-II in FIG. 1
  • Figure 3 - 5 Diagrams of the magnetic field strength over the angle at different distances between two pin magnets and
  • Figure 6 a schematic representation of the arrangement of a magnetic field sensor relative to two pin magnets.
  • An angle measuring device which is suitable, for example, for measuring an angle of rotation of a throttle valve or exhaust gas valve, has a shaft 10, which is connected to an actuator and carries a gear wheel 12.
  • the gear 12 is in clamping engagement with a gear 14 which is connected to a pivot axis 16.
  • the pivot axis 16 is connected, for example, to an axis of the flaps.
  • the one or more flaps can be provided directly on the pivot axis 16.
  • two pin magnets 18, 20 are connected to the gearwheel 14, which is a movement element, as a magnetic field generator.
  • the two pin magnets 18, 20 are arranged on a common circular line and have an angular distance ⁇ from one another.
  • the pin magnets 18, 20 are arranged such that in the case of one pin magnet the north pole and in the other pin magnet the south pole points in the direction of a magnetic field sensor 22 arranged opposite the pin magnet. There is thus a magnetic field between the two pin magnets 18, 20 which is generated by the magnetic field sensor 22, e.g. B. a Hall sensor is detected.
  • the magnetic field sensor is connected via a line 24 to an evaluation unit 26, in particular an evaluation and / or control electronics.
  • the pin magnets are circular cylindrical pin magnets with a diameter of 2 mm and a length of 4 mm.
  • the magnets were magnetized axially. When measured on top, the magnets had a field strength of 250 mT.
  • SmC 05/17 is particularly suitable as the material of the pin magnets. Such pin magnets were used in all three examples listed below.
  • the magnetic field curve runs in the angular range from approximately -82 mT to +87 mT.
  • the exact curve 28 can be stored in the magnetic field sensor or the evaluation device.
  • the curve 28 can be linearized to a straight line 30.
  • the diagram shown in FIG. 4 is based on an investigation in which the two pin magnets 18, 20 were arranged at an angle - 35 ° to one another. As can be seen from the figure, the deviation between the actually recorded curve 32 and the linearized curve 34 is significantly smaller, so that the linearized curve 34 can be stored at an angular range of 35 ° with a relatively high accuracy.
  • the magnetic field sensor 22 (FIG. 5) is at an axial distance d of 5-10 mm in relation to the two pin magnets 18, 20 arranged.
  • the magnetic field sensor is arranged in a region in which a smooth transition takes place between the magnetic field lines 40, 42 of the two pin magnets 18, 20.
  • an angle ⁇ in this area of a smooth transition is greater than 60 °, preferably greater than 90 ° and particularly preferably greater than 120 °.

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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)

Abstract

The invention relates to a measuring device for measuring angles and/or paths, comprising a displacement element (14). A magnetic field producer (18, 20) is connected to the displacement element (14). Said measuring device also comprises a magnetic field sensor (22) which picks up the magnetic field produced by the magnetic field producer (18, 20). The magnetic field sensor (2) is connected to an evaluation device (26) in order to evaluate the picked up magnetic field. The magnetic field producer comprises at least two stud magnets (18, 20) in order to produce a compact and economical measuring device.

Description

MESSVORRICHTUNG ZUR MAGNETISCHEN WINKEL- UND/ODER WEGMESSUNG MEASURING DEVICE FOR MAGNETIC ANGLE AND / OR TRAVEL MEASUREMENT
Die Erfindung betrifft eine Messvorrichtung zur Winkel- und/ oder Wegmessung. Insbesondere betrifft die Erfindung eine Messvorrϊchtung zur Winkel- und/ oder Wegmessung für Stellelemente in Kraftfahrzeugen.The invention relates to a measuring device for angle and / or displacement measurement. In particular, the invention relates to a measuring device for angle and / or displacement measurement for actuating elements in motor vehicles.
Die Winkelmessung, bzw. die Bestimmung einer Stellung einer Schwenkachse, ist bei Kraftfahrzeugelementen beispielsweise zur Steuerung von Drossel- oder Abgasklappen erforderlich. Hierbei muss die Stellung der Klappe exakt bestimmt werden. Eine Vorrichtung zur Bestimmung des Drehwinkels, d. h. des Öffnungswinkels einer Drosselklappe, ist aus DE 199 03 490 bekannt. Hierbei ist die Drosselklappe mit einer Schwenkachse und über mehrere Zwischenelemente mit einem konzentrisch zur Schwenkachse angeordneten Ringmagnet verbunden. Der Ringmagnet wird beim Schwenken der Drosselklappe mitgedreht. In dem Gehäusedeckel sind zwei Magnetfeldsensoren, wie beispielsweise Hall-Sensoren, angeordnet.. Die beiden Sensoren sind außerhalb des Ringmagneten um 180 ° zueinander versetzt angeordnet. Von den beiden Sensoren werden zwei winkelabhängige Signale erzeugt. Die von den beiden Sensoren erzeugten Feldabwicklungskurven sind im Wesentlichen sinusförmig, wobei die Kurven in einem Winkelbereich von ± 45° im Wesentlichen linear sind. Das Vorsehen eines Ringmagneten mit zwei außerhalb des Ringmagneten angeordneten Sensoren erfordert einen großen Bauraum. Dies ist insbesondere bei der Drehwinkelerfassung von Drossel- und Abgasklappen nachteilig, da diese in einem Bereich des Motors angeordnet sind, in dem wenig Platz vorhanden ist.The angle measurement, or the determination of a position of a swivel axis, is necessary in motor vehicle elements, for example for controlling throttle or exhaust flaps. The position of the flap must be determined exactly. A device for determining the angle of rotation, ie the opening angle of a throttle valve, is known from DE 199 03 490. Here, the throttle valve is connected to a pivot axis and, via several intermediate elements, to a ring magnet arranged concentrically to the pivot axis. The ring magnet is rotated when the throttle valve is swiveled. Two magnetic field sensors, such as Hall sensors, are arranged in the housing cover. The two sensors are offset from one another outside the ring magnet by 180 ° arranged. Two angle-dependent signals are generated by the two sensors. The field development curves generated by the two sensors are essentially sinusoidal, the curves being essentially linear in an angular range of ± 45 °. The provision of a ring magnet with two sensors arranged outside the ring magnet requires a large installation space. This is disadvantageous, in particular, when determining the angle of rotation of throttle and exhaust gas flaps, since these are arranged in an area of the engine in which there is little space.
Aufgabe der Erfindung ist es, eine Messvorrichtung zur Winkel- und/ oder Wegmessung zu schaffen, die einen kleinen Bauraum benötigt und kostengünstig herstellbar ist.The object of the invention is to provide a measuring device for angle and / or displacement measurement, which requires a small installation space and can be produced inexpensively.
Die Lösung der Aufgabe erfolgt erfindungsgemäß durch die Merkmale des Anspruchs 1.According to the invention, the object is achieved by the features of claim 1.
Die Messvorrichtung zur Winkel- und/ oder Wegmessung, die insbesondere für Stellelemente in Kraftfahrzeugen geeignet ist, weist ein Bewegungselement, wie ein Zahnrad oder einen Schlitten, auf. Mit dem Bewegungselement ist ein Magnetfelderzeuger verbunden. Dem Magnetfelderzeuger ist ein Magnetfeldsensor zugeordnet, der das von dem Magnetfelderzeuger erzeugte Magnetfeld aufnimmt, bzw. in Abhängigkeit des erfassten Magnetfeldes Signale erzeugt. Hierbei ändert sich durch die Relativbewegung zwischen dem Magnetfelderzeuger und dem Magnetfeldsensor das Magnetfeld, wobei in Abhängigkeit der Magnetfeldänderung ein Signal erzeugt wird. Das von dem Magnetfeldsensor erzeugte Signal wird an eine Auswerteeinrichtung übertragen. Hierbei kann die Auswerteeinrichtung beispielsweise Teil einer Auswerte- und/ oder Steuerelektronik sein, wobei durch die Steuerelektronik beispielsweise das Kraftfahrzeugstellelement gesteuert wird.The measuring device for angle and / or displacement measurement, which is particularly suitable for actuating elements in motor vehicles, has a moving element, such as a gearwheel or a slide. A magnetic field generator is connected to the movement element. A magnetic field sensor is assigned to the magnetic field generator, which detects the magnetic field generated by the magnetic field generator or generates signals as a function of the detected magnetic field. The magnetic field changes due to the relative movement between the magnetic field generator and the magnetic field sensor, a signal being generated as a function of the change in the magnetic field. The signal generated by the magnetic field sensor is transmitted to an evaluation device. Here, the evaluation device can, for example, be part of an evaluation and / or control electronics, the control electronics, for example, controlling the motor vehicle control element.
Erfindungsgemäß weist der Magnetfelderzeuger mindestens zwei in einem Abstand zueinander angeordnete Stiftmagnete auf. Die mindestens zwei Stiftmagnete sind beispielsweise an einem verschwenkbarenAccording to the invention, the magnetic field generator has at least two pin magnets arranged at a distance from one another. The at least two Pen magnets are, for example, on a swiveling one
Bewegungselement in einem Winkel zueinander angeordnet. Ebenso können die Stiftmagnete an einem verschiebbaren Bewegungselement, wie einem Schlitten, in einem linearen Abstand zueinander angeordnet sein. Durch die beiden in einem Abstand zueinander angeordneten Stiftmagnete wird ein Magnetfeld erzeugt, wobei sich die Magnetfeldstärke je nach Lage der Stiftmagneten relativ zu dem Magnetfeldsensor ändert. Hierdurch kann die Lage des Bewegungselementes bestimmt werden. Hierbei besteht die Möglichkeit, dass dem Sensor der Kurvenverlauf des Magnetfeldes in Abhängigkeit der Lage der Stiftmagnete bekannt ist, bzw. in der Auswerteeinheit hinterlegt ist, so dass hieraus die Stellung des Bewegungselementes abgeleitet werden kann. Vorzugsweise sind die Stiftmagnete insbesondere hinsichtlich ihrer Größe und Magnetstärke derart ausgewählt, dass in dem interessierenden Bewegungsbereich ein quasi lineares Magnetfeld zwischen den beiden Stiftmagneten besteht. Dies hat den Vorteil, dass das Hinterlegen bzw. Bestimmen der Magnetfeldkurve nicht erforderlich ist und somit ein einfach aufgebauter Magnetfeldsensor sowie eine entsprechend einfach aufgebaute Auswerteeinheϊt verwendet werden kann.Movement element arranged at an angle to each other. Likewise, the pin magnets can be arranged on a displaceable movement element, such as a carriage, at a linear distance from one another. A magnetic field is generated by the two pin magnets arranged at a distance from one another, the magnetic field strength changing depending on the position of the pin magnets relative to the magnetic field sensor. In this way, the position of the movement element can be determined. There is the possibility that the sensor knows the curve of the magnetic field as a function of the position of the pin magnets or is stored in the evaluation unit, so that the position of the movement element can be derived from this. The pin magnets are preferably selected, in particular with regard to their size and magnetic strength, in such a way that there is a quasi-linear magnetic field between the two pin magnets in the range of motion of interest. This has the advantage that it is not necessary to store or determine the magnetic field curve, and thus a simply constructed magnetic field sensor and a correspondingly simply constructed evaluation unit can be used.
Das Vorsehen von Stiftmagneten hat den Vorteil, dass es sich hierbei um kleine Bauteile handelt und die aus dem Stand der Technik bekannten kreisförmigen, insbesondere diametral magnetisϊerten Magnete entfallen können. Die erfindungsgemäße Messvorrichtung erfordert somit nur einen kleinen Bauraum und ist sehr kostengünstig herstellbar.The provision of pin magnets has the advantage that these are small components and the circular, in particular diametrically magnetized magnets known from the prior art can be omitted. The measuring device according to the invention thus requires only a small installation space and can be produced very inexpensively.
Bei einer besonders bevorzugten Ausführungsform der erfindungsgemäßen Messvorrichtung ist nur ein einziger Magnetfeldsensor vorgesehen. Hierdurch kann der Bauraum weiter reduziert und die Kosten der Messvorrichtung weiter verringert werden. Bei dem Magnetfeldsensor handelt es sich vorzugsweise um einen Hall-Sensor, insbesondere einen stützstellenprogrammierbaren Hall-Sensor. Mit Hilfe von Hall-Sensoren kann das Magnetfeld exakt erfasst werden.In a particularly preferred embodiment of the measuring device according to the invention, only a single magnetic field sensor is provided. This further reduces the installation space and further reduces the cost of the measuring device. The magnetic field sensor is preferably a Hall sensor, in particular a Hall sensor that can be programmed as a support point. With the help of Hall sensors, the magnetic field can be detected precisely.
Vorzugsweise sind die Stiftmagnete derart ausgerichtet, dass ihre i\lord-Süd- Ausrichtung im Wesentlichen senkrecht zu der Bewegungsrichtung ist. Hierdurch ist sichergestellt, dass das zwischen den beiden Stiftmagneten bestehende Magnetfeld vom Magnetfeldsensor gut erfasst werden kann.The pin magnets are preferably oriented such that their i \ lord-south orientation is essentially perpendicular to the direction of movement. This ensures that the magnetic field between the two pin magnets can be detected well by the magnetic field sensor.
Bei einer besonders bevorzugten Ausführungsform der Messvorrichtung handelt es sich um eine Vorrichtung zur Drehwinkelerfassung für Drossel- und/ oder Abgasklappen in Kraftfahrzeugen. Hierbei ist eine Schwenkachse, die vorzugsweise unmittelbar mit der Klappe verbunden ist, vorgesehen. Zur Erfassung des Schwenkwinkels der Schwenkachse ist in einem Abstand zur Mittellinie der Schwenkachse der Magnetfelderzeuger in Form von mindestens zwei Stiftmagneten angeordnet. Hierbei sind die beiden Stiftmagnete vorzugsweise auf einer Kreislinie angeordnet. Benachbart zu den Stiftmagneten, bzw. zu dem von den Stiftmagneten erzeugten Magnetfeld, ist der Magnetfeldsensor angeordnet. Somit erfolgt durch Schwenken der Schwenkachse eine Relatϊvbewegung zwischen den Stiftmagneten und dem Magnetfeldsensor. Hierdurch ändert sich das Magnetfeld, das der Magnetfeldsensor aufnimmt. In Abhängigkeit der Magπetfeldänderung erzeugt, der Magnetfeldsensor ein winkelabhängiges Signal. Ggf. ist zur Bestimmung des exakten Winkels eine Auswerteeinheit erforderlich, die das Signal des Magnetfeldsensors entsprechend verarbeitet.A particularly preferred embodiment of the measuring device is a device for detecting the angle of rotation for throttle and / or exhaust gas flaps in motor vehicles. Here, a pivot axis, which is preferably connected directly to the flap, is provided. To detect the swivel angle of the swivel axis, the magnetic field generator in the form of at least two pin magnets is arranged at a distance from the center line of the swivel axis. Here, the two pin magnets are preferably arranged on a circular line. The magnetic field sensor is arranged adjacent to the pin magnets or to the magnetic field generated by the pin magnets. Thus, by pivoting the pivot axis, there is a relative movement between the pin magnet and the magnetic field sensor. This changes the magnetic field that the magnetic field sensor receives. Depending on the change in magnetic field, the magnetic field sensor generates an angle-dependent signal. Possibly. an evaluation unit is required to determine the exact angle, which processes the signal of the magnetic field sensor accordingly.
Bei einer besonders bevorzugten Ausführungsform ist der Magnetfeldsensor in einem derartigen, insbesondere axialen Abstand zu den Magnetfelderzeugern angeordnet, dass im Bereich des Magnetfeldsensors die Magnetfeldlinien der beiden Magnetfelderzeuger einen sanften Übergang zueinander aufweisen. Dieser erfindungsgemäßen bevorzugten Anordnung liegt die Erkenntnis zu Grunde, dass die Feldlinien bei einem geringen Abstand zueinander in einem sehr spitzen Winkel zueinander verlaufen, d. h. keinen sanften Übergang bilden. Mit Erhöhung des axialen Abstandes wird der Übergang zwischen den Feldlinien sanfter, jedoch wird mit Vergrößerung des Abstandes die Feldstärke geringer. In Abhängigkeit der von dem Magneten erzeugten Magnetfeldstärke kann somit ein optimaler Abstand bestimmt werden, an dem insbesondere auch in Abhängigkeit der Empfindlichkeit des Magnetfeldsensors die Magnetfeldstärke noch ausreichend ist und somit ein möglichst sanfter Übergang der Magnetfeldlϊnien gegeben ist. Bei dem sanften Übergang handelt es sich insbesondere um einen Winkel zwischen den sich schneidenden Magnetfeldlinien der beiden Magnetfelder von mehr als 60°, insbesondere mehr als 90° und besonders bevorzugt mehr als 120°. Hierbei ist zu berücksichtigen, dass die von den beiden Magnetfelderzeugern erzeugten Magnetfelder von den Außenabmessungen, insbesondere dem Durchmesser der Magnetfelderzeuger, von dem Material und von deren axialer Ausdehnung abhängig ist. Die optimale Lage des Magnctfeldsensors im Bezug auf die Magnetfelderzeuger kann durch Versuche ermittelt werden. Hierbei wird der Magnetfeldsensor derart angeordnet, dass in dem interessierenden Winkelbereich ein im Wesentlichen linearer Verlauf der Magnetfeldlinie gegeben ist.In a particularly preferred embodiment, the magnetic field sensor is arranged at such an, in particular axial, distance from the magnetic field generators that the magnetic field lines of the two magnetic field generators have a smooth transition from one another in the region of the magnetic field sensor. This preferred arrangement according to the invention is based on the knowledge that the field lines are at a small distance from one another in one very acute angles to each other, ie do not form a smooth transition. As the axial distance increases, the transition between the field lines becomes smoother, but as the distance increases, the field strength decreases. Depending on the magnetic field strength generated by the magnet, an optimal distance can be determined at which the magnetic field strength is still sufficient, in particular also depending on the sensitivity of the magnetic field sensor, and thus the smoothest possible transition of the magnetic field lines is given. The smooth transition is, in particular, an angle between the intersecting magnetic field lines of the two magnetic fields of more than 60 °, in particular more than 90 ° and particularly preferably more than 120 °. It must be taken into account here that the magnetic fields generated by the two magnetic field generators depend on the external dimensions, in particular the diameter of the magnetic field generators, on the material and on their axial extension. The optimal position of the magnetic field sensor in relation to the magnetic field generators can be determined by experiments. The magnetic field sensor is arranged in such a way that there is an essentially linear profile of the magnetic field line in the angle region of interest.
Nachfolgend wird die Erfindung an Hand einer bevorzugten Ausführungsform unter Bezugnahme auf die anliegenden Zeichnungen näher erläutert.The invention is explained in more detail below on the basis of a preferred embodiment with reference to the attached drawings.
Es zeigen :Show it :
Figur 1 : eine schematische Draufsicht einer Winkel- Messvorrichtung,FIG. 1: a schematic top view of an angle measuring device,
Figur 2 : eine schematische Seitenansicht entlang der Linie II-II in Figur 1, Figur 3 - 5 : Diagramme der Magnetfeldstärke über dem Winkel bei unterschiedlichen Abständen von zwei Stiftmagneten undFIG. 2: a schematic side view along the line II-II in FIG. 1, Figure 3 - 5: Diagrams of the magnetic field strength over the angle at different distances between two pin magnets and
Figur 6: eine schematische Darstellung der Anordnung eines Magnetfeldsensors relativ zu zwei Stiftmagneten.Figure 6: a schematic representation of the arrangement of a magnetic field sensor relative to two pin magnets.
Eine Winkelmessvorrichtung, die beispielsweise zum Messen eines Drehwinkel einer Drosselklappe oder Abgasklappe geeignet ist, weist eine mit einem Stellmotor verbundene Welle 10 auf, die ein Zahnrad 12 trägt. Das Zahnrad 12 ist in klemmendem Eingriff mit einem Zahnrad 14, das mit einer Schwenkachse 16 verbunden ist. Die Schwenkachse 16 ist beispielsweise mit einer Achse der Klappen verbunden. Ebenso können die eine oder mehrere Klappen unmittelbar auf der Schwenkachse 16 vorgesehen sein.An angle measuring device, which is suitable, for example, for measuring an angle of rotation of a throttle valve or exhaust gas valve, has a shaft 10, which is connected to an actuator and carries a gear wheel 12. The gear 12 is in clamping engagement with a gear 14 which is connected to a pivot axis 16. The pivot axis 16 is connected, for example, to an axis of the flaps. Likewise, the one or more flaps can be provided directly on the pivot axis 16.
Um einen Schwenkwinkel der Schwenkachse 16 und somit beispielsweise die Lage einer Klappe bestimmen zu können, sind mit dem Zahnrad 14, bei dem es sich um ein Bewegungselement handelt, als Magnetfelderzeuger zwei Stiftmagnete 18, 20 verbunden. Im dargestellten Ausführungsbeispiel sind die beiden Stiftmagnete 18, 20 auf einer gemeinsamen Kreislinie angeordnet und weisen einen Winkelabstand α zueinander auf. Die Stiftmagnete 18, 20 sind derart angeordnet, dass bei dem einem Stiftmagnet der Nordpol und bei dem anderen Stiftmagnet der Südpol in Richtung eines gegenüber den Stiftmagneten angeordneten Magnetfeldsensors 22 weist. Zwischen den beiden Stiftmagneten 18, 20 besteht somit ein Magnetfeld, das vom Magnetfeldsensor 22, z. B. einem Hall-Sensor erfasst wird. Über eine Leitung 24 ist der Magnetfeldsensor mit einer Auswerteeinheit 26, insbesondere einer Auswert- und/oder Steuerelektronik verbunden.In order to be able to determine a swivel angle of the swivel axis 16 and thus, for example, the position of a flap, two pin magnets 18, 20 are connected to the gearwheel 14, which is a movement element, as a magnetic field generator. In the exemplary embodiment shown, the two pin magnets 18, 20 are arranged on a common circular line and have an angular distance α from one another. The pin magnets 18, 20 are arranged such that in the case of one pin magnet the north pole and in the other pin magnet the south pole points in the direction of a magnetic field sensor 22 arranged opposite the pin magnet. There is thus a magnetic field between the two pin magnets 18, 20 which is generated by the magnetic field sensor 22, e.g. B. a Hall sensor is detected. The magnetic field sensor is connected via a line 24 to an evaluation unit 26, in particular an evaluation and / or control electronics.
In den in den Figuren 3 - 5 dargestellten Diagrammen wurde der Verlauf der Magnetfeld kurve in Abhängigkeit des Winkels aufgenommen, wobei die beiden Stiftmagnete 18, 20 in einem unterschiedlichen Winkel zueinander mit dem Zahnrad 14 verbunden waren.In the diagrams shown in Figures 3-5, the course of the magnetic field curve was recorded depending on the angle, the two Pin magnets 18, 20 were connected to the gearwheel 14 at a different angle to one another.
Bei den Stiftmagneten handelt es sich um kreiszylinderförmige Stiftmagnefe mit einem Durchmesser von 2 mm und einer Länge von 4 mm. Die Magnete waren axial magnetisiert. Aufliegend gemessen wiesen die Magnete eine Feldstärke von 250 mT auf. Als Material der Stiftmagnete ist insbesondere SmC 05/17 geeignet. Derartige Stiftmagnete wurden in allen drei nachfolgend aufgeführten Beispielen eingesetzt.The pin magnets are circular cylindrical pin magnets with a diameter of 2 mm and a length of 4 mm. The magnets were magnetized axially. When measured on top, the magnets had a field strength of 250 mT. SmC 05/17 is particularly suitable as the material of the pin magnets. Such pin magnets were used in all three examples listed below.
Bei der Figur 3 wurden die Stiftmagnete 18, 20 in einem Winkel α = 45° zueinander angeordnet.In FIG. 3, the pin magnets 18, 20 were arranged at an angle α = 45 ° to one another.
Wie sich aus Figur 3 ergibt, verläuft die Magnetfeldkurve in dem Winkelbereich von ca. -82 mT bis +87 mT. Erfindungsgemäß kann dem Magnetfeldsensor bzw. der Auswerteeinrichtung die exakte Kurve 28 hinterlegt werden. In einer einfachen Ausgestaltung der Erfindung, die ausreichend ist, wenn der Drehwinkel nicht exakt bestimmt werden muss, kann die Kurve 28 zu einer Geraden 30 linearisiert werden. Wenngleich die Messung hierdurch eine gewisse Ungenauigkeit erfährt, weist dies den Vorteil auf, dass die Winkelbestimmung in Abhängigkeit des gemessenen Magnetfeldes erheblich einfacher ist.As can be seen from FIG. 3, the magnetic field curve runs in the angular range from approximately -82 mT to +87 mT. According to the invention, the exact curve 28 can be stored in the magnetic field sensor or the evaluation device. In a simple embodiment of the invention, which is sufficient if the angle of rotation does not have to be determined exactly, the curve 28 can be linearized to a straight line 30. Although the measurement experiences a certain degree of inaccuracy, this has the advantage that the angle determination depending on the measured magnetic field is considerably easier.
Dem in Figur 4 dargestellten Diagramm liegt eine Untersuchung zu Grunde, bei der die beiden Stiftmagnete 18, 20 in einem Winkel - 35° zueinander angeordnet waren. Wie aus der Figur ersichtlich, ist die Abweichung zwischen der tatsächlich aufgenommenen Kurve 32 und der linearisierten Kurve 34 deutlich geringer, so dass bei einem Winkelbereich von 35° bereits bei einer relativ hohen Genauigkeit die linearisierte Kurve 34 hinterlegt werden kann.The diagram shown in FIG. 4 is based on an investigation in which the two pin magnets 18, 20 were arranged at an angle - 35 ° to one another. As can be seen from the figure, the deviation between the actually recorded curve 32 and the linearized curve 34 is significantly smaller, so that the linearized curve 34 can be stored at an angular range of 35 ° with a relatively high accuracy.
Das in Figur 5 dargestellte Diagramm wurde auf Basis eines Winkelabstandes von = 23° ermittelt. Hierbei wurde festgestellt, dass der Unterschied zwischen der tatsächlichen Magnetfeldkurve 36 und der linearisϊeiten Kurve 38 noch geringer ist, so dass bei einem derartigen Winkelbereich insbesondere bei Stellelementen in einem Kraftfahrzeug und der linearisierten Kurve ausgegangen werden kann.The diagram shown in FIG. 5 was determined on the basis of an angular distance of = 23 °. It was found that the difference between the actual magnetic field curve 36 and the linear curve 38 is even smaller, so that with such an angular range it can be assumed in particular in the case of actuating elements in a motor vehicle and the linearized curve.
Bei einer besonders bevorzugten Ausführungsform der Erfindung bei der insbesondere die in den Figuren 4 und 5 dargestellten Messergebnisse erzielt werden können, ist der Magnetfeldsensor 22 (Fig. 5) bezogen auf die beiden Stiftmagnete 18, 20 in einem axialen Abstand d von 5 - 10 mm angeordnet. Dies hat zur Folge, dass der Magnetfeldsensor in einem Bereich angeordnet ist, in dem zwischen den Magnetfeldlinien 40, 42 der beiden Stiftmagneten 18, 20 ein sanfter Übergang stattfindet. Insbesondere ist ein Winkel \\ in diesem Bereich eines sanften Übergangs größer als 60°, vorzugsweise größer als 90° und besonders bevorzugt größer als 120°. In a particularly preferred embodiment of the invention, in which in particular the measurement results shown in FIGS. 4 and 5 can be achieved, the magnetic field sensor 22 (FIG. 5) is at an axial distance d of 5-10 mm in relation to the two pin magnets 18, 20 arranged. As a result, the magnetic field sensor is arranged in a region in which a smooth transition takes place between the magnetic field lines 40, 42 of the two pin magnets 18, 20. In particular, an angle \\ in this area of a smooth transition is greater than 60 °, preferably greater than 90 ° and particularly preferably greater than 120 °.

Claims

Patentansprüche claims
1. Messvorrichtung zur Winkel- und/ oder Wegmessung, mit einem Bewegungselement (14), einem mit dem Bewegungselement ( 14) verbundenen Magnetfelderzeuger (18, 20), einem das durch den Magnetfelderzeuger ( 18, 20) erzeugte Magnetfeld aufnehmenden Magnetfeldsensor (22) und einer mit dem Magnetfeldsensor (22) verbundenen Auswerteeinheit (26), dad u rch gekennzei ch net, dass der Magnetfelderzeuger mindestens zwei in einem Abstand zueinander angeordnete Stiftmagnete (18, 20) aufweist.1. Measuring device for angle and / or displacement measurement, with a movement element (14), a magnetic field generator (18, 20) connected to the movement element (14), a magnetic field sensor (22) that detects the magnetic field generated by the magnetic field generator (18, 20) and an evaluation unit (26) connected to the magnetic field sensor (22), so that the magnetic field generator has at least two pin magnets (18, 20) arranged at a distance from one another.
2. Messvorrichtung nach Anspruch 1, dadurch gekennzeichnet, dass die Stiftmagnete (18, 20) insbesondere hinsichtlich der Größe und/ oder der Stärke derart ausgewählt sind, dass ein quasi lineares Magnetfeld zwischen den Stiftmagneten (18, 20) besteht.2. Measuring device according to claim 1, characterized in that the pin magnets (18, 20) are selected in particular with regard to their size and / or strength such that there is a quasi-linear magnetic field between the pin magnets (18, 20).
3. Messvorrichtung nach Anspruch 1 oder 2, dadurch gekennzeichnet, dass der Magnetfeldsensor (22) ein Hall-Sensor, insbesondere ein stützstellenprogrammierbarer Hall-Sensor ist.3. Measuring device according to claim 1 or 2, characterized in that the magnetic field sensor (22) is a Hall sensor, in particular a support point programmable Hall sensor.
4. Messvorrichtung nach einem der Ansprüche 1 - 3, dadurch gekennzeichnet, dass die Ausrichtung der Stiftmagnete (18, 20) im Wesentlichen senkrecht zu ihrer Bewegungsrϊchtung ist. 4. Measuring device according to one of claims 1-3, characterized in that the orientation of the pin magnets (18, 20) is substantially perpendicular to their direction of movement.
5. Messvorrichtung nach einem der Ansprüche 1 - 4, dadurch gekennzeichnet, dass das Bewegungselement (14) ein Zahnrad oder eine Scheibe ist.5. Measuring device according to one of claims 1-4, characterized in that the movement element (14) is a gear or a disc.
6. Messvorrichtung nach einem der Ansprüche 1 - 4, dadurch gekennzeichnet, dass das Bewegungselement (14) eine Schwenkachse (16) aufweist und die Stiftmagnete (18, 20) auf einer Kreislinie im Abstand zu der Schwenkachse (16) angeordnet sind.6. Measuring device according to one of claims 1-4, characterized in that the movement element (14) has a pivot axis (16) and the pin magnets (18, 20) are arranged on a circular line at a distance from the pivot axis (16).
7. Messvorrichtung nach einem der Ansprüche 1 - 6, dadurch gekennzeichnet, dass ein insbesondere axialer Abstand (d) zwischen den Magnetfelderzeugern (18, 20) und dem Magnetfeldsensor (22) derart gewählt ist, dass die Magnetfeldlϊnien (40, 42) der Magnetfelderzeuger (18, 20) einen sanften Übergang zueinander aufweisen. 7. Measuring device according to one of claims 1-6, characterized in that an in particular axial distance (d) between the magnetic field generators (18, 20) and the magnetic field sensor (22) is selected such that the magnetic field lines (40, 42) of the magnetic field generators (18, 20) have a smooth transition to one another.
EP05749254A 2004-06-17 2005-06-08 Measuring device for measuring magnetic angles and/ or paths Withdrawn EP1756525A1 (en)

Applications Claiming Priority (2)

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DE102004029339A DE102004029339A1 (en) 2004-06-17 2004-06-17 Measuring device for angle and / or distance measurement
PCT/EP2005/052642 WO2005124284A1 (en) 2004-06-17 2005-06-08 Measuring device for measuring magnetic angles and/ or paths

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DE102008058525A1 (en) * 2008-11-21 2010-05-27 Mahle International Gmbh Actuating device, valve device and operating method

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GB2229006A (en) * 1989-03-10 1990-09-12 Jaguar Cars Rotary position transducer
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