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WO2005036195A1 - Detecteur d'approche sans contact, notamment pour des elements ferromagnetiques - Google Patents

Detecteur d'approche sans contact, notamment pour des elements ferromagnetiques Download PDF

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Publication number
WO2005036195A1
WO2005036195A1 PCT/CH2004/000587 CH2004000587W WO2005036195A1 WO 2005036195 A1 WO2005036195 A1 WO 2005036195A1 CH 2004000587 W CH2004000587 W CH 2004000587W WO 2005036195 A1 WO2005036195 A1 WO 2005036195A1
Authority
WO
WIPO (PCT)
Prior art keywords
proximity detector
magnets
hall sensor
hall
detector according
Prior art date
Application number
PCT/CH2004/000587
Other languages
German (de)
English (en)
Inventor
Joshua Lanter
Martin Kirchner
Original Assignee
Polycontact Ag
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 Polycontact Ag filed Critical Polycontact Ag
Priority to DE112004001822T priority Critical patent/DE112004001822D2/de
Publication of WO2005036195A1 publication Critical patent/WO2005036195A1/fr

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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
    • G01D5/147—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 movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other

Definitions

  • Non-contact proximity detector especially for erromagnetic components
  • the invention relates to a non-contact proximity detector, in particular for detecting ferromagnetic components, according to the preamble of patent claim 1.
  • Hall sensors are often used as proximity sensors or as contactless sensors
  • Hall sensors consist of a semiconductor layer supplied with constant current, usually in an integrated design.
  • the constant current is influenced by a magnetic field component perpendicular to the semiconductor layer and the sensor supplies an evaluable Hall voltage which can be tapped and used to evaluate a state or can also be used directly as a switching voltage.
  • the integrated design of Hall sensors offers the possibility of integrating an evaluation circuit suitable for evaluating the switching state on the Hall sensor.
  • a contactless proximity detector for ferromagnetic components is known from US Pat. No. 6,043,646, which can be used in particular for motor vehicle applications.
  • the proximity detector has a U-shaped permanent magnet with a vertical magnetization running parallel to the U-legs. A region free of magnetic flux is formed between the U-legs, in which a sensor sensitive to a magnetic field is attached.
  • a flat ferromagnetic release part approaches parallel to the extension of the base of the U-shaped permanent magnet to the free poles of the U-legs, the area free of magnetic flux between the U-legs is canceled and the magnetic field-sensitive sensor arranged there generates a signal which is evaluated can.
  • the construction of the proximity detector with a U-shaped permanent magnet and a magnetic field-sensitive sensor arranged between the U-legs is required. very high precision.
  • the U-legs running on both sides of the base of the U-shaped permanent magnet have to be as similar as possible and aligned as exactly as possible so that a space free of magnetic flux is created in the area enclosed by the U-shaped permanent magnet.
  • the production of a special U-shaped permanent magnet is intrinsically complex and expensive.
  • the required accuracy of the U-shaped permanent magnet and the complex adjustment of the magnetic field-sensitive sensors make the non-contact proximity detector even more expensive. For this reason, components of this type can only be used for special applications in which the costs play a subordinate role.
  • Object of the present invention is therefore / creating ⁇ a contactless proximity detector which is simple in construction. It should be simple and inexpensive to manufacture. In particular, the proximity detector should be able to be manufactured from simple standard components.
  • the contactless proximity detector according to the invention in particular for detecting the approach of a ferromagnetic component, has at least one magnet arrangement generating a magnetic flux and a magnetic field-sensitive sensor arranged in the effective range of the magnetic flux.
  • the magnetic field sensitive sensor is a Hall sensor with at least one flat Hall measuring field. The vector of the magnetic flux within the magnet arrangement runs parallel to the areal extension of the Hall measuring field.
  • the proximity detector according to the invention has a very simple construction consisting of at least one conventional magnet and a Hall sensor with at least one Hall measuring field.
  • the only condition is that the orientation of the magnetic field formed by the magnet inside the magnet parallel to the areal extension of the Hall measuring field runs. In other words, this means that the direction of the magnetic flux of the bias magnet is perpendicular to the direction of the measured variable measured in the Hall measuring field.
  • the magnetic field of the bias magnet is distorted and the amount of the measured variable tapped at the Hall measuring field changes.
  • the tapped measurement variable can be processed further or, after any amplification, can be used immediately to trigger a switching pulse.
  • the components used for the proximity detector are standard components that are simple and inexpensive to manufacture and assemble. Because of its simple and inexpensive design, the proximity detector can be used anywhere where the change in position of a ferromagnetic component is to be detected.
  • the Hall sensor and the magnet arrangement are expediently arranged such that they can be moved relative to one another at least in a direction running perpendicular to the direction of the vector of the magnetic flux.
  • the relative mobility of the individual components facilitates the adjustment and calibration of the proximity detector.
  • the proximity detector according to the invention comprises only a single magnet and the Hall sensor with at least one Hall measuring field.
  • a further embodiment variant of the proximity detector comprises two magnets arranged at a distance from one another, the magnetic fluxes running within the magnets being parallel and preferably directed in opposite directions.
  • the Hall sensor is arranged in a neutral area which is formed in a space between the two magnets. This neutral area is not a completely magnetic field-free area; rather the effect of the magnetic flux in this zone is canceled out.
  • the two bias magnets improve the sensitivity of the proximity detector without unduly increasing the complexity of the system.
  • FIG. 1 For purposes of this specification, the proximity detector according to the invention can also comprise three or more magnets, each of which is arranged in such a way that their magnetic fluxes within the magnets run parallel to the planar extent of the Hall measuring field.
  • the magnets are arranged in such a way that the vectors of the magnetic fluxes of at least two opposing magnets are directed towards each other.
  • a zone can be created in which the effects of the magnetic fluxes cancel each other out in a coordinate direction.
  • these are advantageously arranged and oriented such that the vectors of the magnetic fluxes of all magnets point in the direction of the Hall sensor or in the opposite direction.
  • the magnetic fluxes cross each other in pairs. Due to the simultaneous orientation of the magnetic fluxes in the direction of the Hall sensor or away from it, the ineffective zone in which the Hall sensor is arranged can be defined very easily. Relative mobility of the magnets relative to one another facilitates the exact alignment of the magnetic fluxes with respect to one another.
  • the magnet arrangement can be formed, for example, by one or more electromagnets which can be activated if necessary.
  • the magnet arrangement comprises at least one rod-shaped permanent magnet. This has the advantage that no separate energy source is required and the proximity detector is practically always on standby.
  • the Hall sensor can be designed as a differential Hall sensor.
  • the differential Hall sensor has at least two Hall measuring fields which are arranged next to or behind one another in relation to the direction of the vector of the magnetic flux. Since the magnetic field sensitive sensor is designed as a differential Hall sensor with two measuring fields, magnetic field differences can be measured with the sensor. When forming the difference between the signals supplied by the Hall measuring fields, interference from external magnetic fields is eliminated. Because of the largely insensitivity of the differential Hall sensor to external interference magnetic fields, even minor changes in the magnetic field acting on the differential Hall sensor can be detected.
  • the linear arrangement of the Hall measuring fields one behind the other or next to one another takes into account the fact that the movement of the position-changing components is essentially linear.
  • the proximity detector comprises a Hall sensor, the characteristics of which, such as the point of use, switching threshold, slope, etc., can be subsequently trimmed, in particular programmed. Subsequent trimming can consist, for example, of activating or deactivating diodes on the Hall sensor or subsequently changing resistance sections, for example with a laser, etc.
  • Programmable Hall sensors have a control unit, for example in the form of an EPROMS or EEPROMS, which it allows the desired parameters to be adjusted and changed as required. As a result, the area of application of the proximity detector can be specifically adapted to the requirements.
  • Figure 1 shows a first embodiment of an inventive proximity detector with a magnet and a Hall sensor.
  • FIG. 2 shows a second embodiment of the proximity detector with a Hall sensor arranged between two magnets
  • FIG. 3 shows a variant of the proximity detector according to FIG. 1;
  • FIG 4 shows another embodiment of the proximity detector according to the invention.
  • the embodiment variant of the proximity detector 10 shown schematically in FIG. 1 comprises a magnet 11 and a magnetic field-sensitive sensor 15, which is arranged in the effective range of the magnetic flux J of the magnet 11.
  • a mag Net field-sensitive sensor 15 is, in particular, a Hall sensor with a flat Hall measuring field 16.
  • the magnet 11 is designed as a bar magnet. N and S denote the magnetic north pole and the magnetic south pole of the ring magnet.
  • the bar magnet 11 is arranged such that the magnetic flux J inside the magnet 11 runs parallel to the surface of the Hall measuring field 16 of the Hall sensor 15.
  • a ferromagnetic component 3 approaches, which is indicated in the illustration by the double arrow P, the magnetic flux J is changed to a greater or lesser extent.
  • the change in the magnetic flux J due to the approach of the component 3 is detected.
  • an electromagnetic signal is generated, for example, when a threshold value is reached, which is tapped at Hall measuring field 16 and can be used, for example, to initiate a switching process.
  • the Hall sensor 25 and its bias magnet 21 are advantageously arranged to be displaceable relative to one another.
  • the embodiment of the proximity detector 20 shown in FIG. 2 measures a Hall sensor 25 with a Hall measuring field 26, which is arranged between two bar magnets 21, 22 arranged at a distance from one another.
  • the bar magnets 21, 22 are aligned with their north and south poles N and S such that their magnetic fluxes within the magnets 21 and 22 run parallel to the surface of the Hall measuring field 26 of the Hall sensor 25.
  • the Hall sensor 25 is advantageously arranged between the two magnets 21, 22 in such a way that the Hall measuring field 26 is located in the region of the flow-free zone. As a result, the greatest possible sensitivity of the Hall sensor 25 to flow changes can be achieved.
  • the components of the proximity detector 20 are advantageously arranged such that they can be adjusted relative to one another.
  • a ferromagnetic component 3 approaches, the magnetic flux J is distorted and the flux-free zone in which the Hall measuring field is arranged is canceled.
  • the change in the magnetic flux is detected by the Hall sensor 25 and converted into electrical signals that are processed further.
  • the magnetic fluxes J of the two magnets 21, 22 are directed towards the Hall sensor 25 in FIG. 2. It goes without saying that the magnets 21, 22 also in this way can be arranged that the magnetic fluxes m Hall sensor 25 directed away.
  • the design variant of the proximity detector 30 shown schematically in FIG. 3 largely corresponds in structure to the exemplary embodiment from FIG. 1.
  • the proximity detector comprises a magnet 31 and a magnetic field sensitive sensor 35 which is arranged in the effective range of the magnetic flux J of the magnet 31.
  • the magnetic field-sensitive sensor 35 is a differential Hall sensor which has at least two flat Hall measuring fields 36, 37.
  • the magnet 31 is in turn designed as a bar magnet. N and S denote the magnetic north pole and the magnetic south pole of the ring magnet.
  • the bar magnet 31 is arranged such that the magnetic flux J inside the magnet 31 runs parallel to the surface of the two Hall measurement fields 36 and 37 of the Hall sensor 35. A relative displacement of the bias magnet 31 and the Hall sensor 35 to each other facilitates the alignment of the components.
  • the magnetic flux J is changed to a greater or lesser extent.
  • the two Hall measuring fields 36, 37 detect the locally different flow change.
  • the resulting electromagnetic signals are used to form the difference. In this way, interference from external electromagnetic stray or interference fields can be eliminated.
  • the electrical differential signals supplied by the differential Hall sensor 35 are a direct measure of the change in position of the ferromagnetic component 3 and can be processed further or used for direct switching operations or the like.
  • the exemplary embodiment of the proximity detector according to the invention shown in FIG. 4 is provided with the reference number 40 as a whole. It comprises four magnets 41, 42, 43, 44, which are designed, for example, as rod-shaped permanent magnets and are mounted so as to be displaceable relative to one another.
  • the bar magnets 41-44 are arranged in a rectangular shape and enclose an area in which a Hall sensor 45 with a flat Hall measuring field 46 is arranged.
  • the position of the Hall sensor 45 relative to the bar magnets 41-44 can be changed.
  • the orientation of the bias magnets 41-44 for the Hall sensor 45 is such that the direction of the magnetic flux J is within the magnets 41 - 44 run parallel to the surface of the flat Hall measuring field 46 of the Hall sensor 45.
  • the north and south poles N and S of mutually opposite magnets 41, 42 and 43, 44 are oriented in such a way that the magnetic fluxes J of a magnet pair 41, 42 and 43, 44 run parallel but opposite to each other.
  • the magnets 41-44 are oriented such that the magnetic fluxes J run perpendicular to one another in pairs.
  • the direction of all magnetic fluxes J is oriented away from the Hall sensor 45. It goes without saying that the direction of the magnetic fluxes can also be reversed.
  • the orientation of the magnets can also be chosen such that the directions of the magnetic fluxes of a magnet pair lying opposite one another point toward the Hall sensor, while the magnetic fluxes of the second magnet pair point away from the Hall sensor.
  • a ferromagnetic component 3 approaches, which is indicated by the double arrow P, the magnetic flux in the area enclosed by the biasing magnets 41-44 is changed and detected by the Hall sensor. The resulting electrical parameters are tapped and processed.
  • a differential Hall sensor with at least two Hall measuring fields can be used instead of a Hall sensor.
  • the proximity detector comprises a Hall sensor, the parameters of which, such as the point of use, switching threshold, slope, etc., can be subsequently trimmed, in particular programmed.
  • a subsequent trimming can consist, for example, that the Hall sensor has diodes which can be activated or deactivated subsequently in order to change its parameters.
  • the Hall sensor can also be equipped with resistance paths, for example, which can be changed later, for example with a laser.
  • Programmable Hall sensors have a control unit, for example in the form of an EPROMS or EEPROMS, which allows the desired parameters to be adapted and changed as desired. As a result, the area of application of the proximity detector can be specifically adapted to the requirements.
  • the component 3 shown in FIGS. 1-4 whose approach is to be determined by the proximity detector, is not made entirely of a ferromagnetic see material must exist. It can also be a component made of other materials, which is connected to or encloses a ferromagnetic part, etc.
  • the proximity sensor described can be used wherever the approach of a component having a ferromagnetic component is detected and for triggering further processes , for example of switching operations, is used.
  • One application is, for example, the detection of the closure of a seat belt buckle in motor vehicles, which serves as an indicator for the activation or deactivation of mechanisms for inflating driver and front passenger airbags or side airbags.

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

Abstract

L'invention concerne un détecteur d'approche (10) sans contact, notamment pour capter l'approche d'un élément ferromagnétique (3), ce détecteur comportant au moins un ensemble aimant (11) générant un flux magnétique (J) et un capteur (15) sensible aux champs magnétiques placé dans le champ d'action du flux magnétique (J). L'invention est caractérisée en ce que le capteur (15) sensible aux champs magnétiques est un capteur Hall doté d'au moins un champ de mesure Hall (16) plan, le vecteur du flux magnétique (J) à l'intérieur de l'ensemble aimant (11) étant parallèle à l'étendue plane du champ de mesure Hall (16).
PCT/CH2004/000587 2003-10-14 2004-09-17 Detecteur d'approche sans contact, notamment pour des elements ferromagnetiques WO2005036195A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DE112004001822T DE112004001822D2 (de) 2003-10-14 2004-09-17 Berührungsloser Näherungsdetektor, insbesondere für ferromagnetische Bauteile

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CH17472003 2003-10-14
CH1747/03 2003-10-14

Publications (1)

Publication Number Publication Date
WO2005036195A1 true WO2005036195A1 (fr) 2005-04-21

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PCT/CH2004/000587 WO2005036195A1 (fr) 2003-10-14 2004-09-17 Detecteur d'approche sans contact, notamment pour des elements ferromagnetiques

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DE (1) DE112004001822D2 (fr)
WO (1) WO2005036195A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1759920A1 (fr) * 2005-08-31 2007-03-07 Hella KG Hueck & Co. Dispositif pour la détermination de la position nominale d'un projecteur pivotant d'automobile
DE102007030705B3 (de) * 2007-07-02 2009-02-05 Continental Automotive Gmbh Näherungsschalter
US20130055575A1 (en) * 2010-03-24 2013-03-07 Infaco Sas Device for controlling the relative positioning of two elements, such as the blades of secateur-type cutting tools, and a cutting tool comprising same

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4066962A (en) * 1976-12-08 1978-01-03 The Singer Company Metal detecting device with magnetically influenced Hall effect sensor
US5128613A (en) * 1985-02-25 1992-07-07 Kubota Ltd. Method of inspecting magnetic carburization in a non-permeable material and probe therefore
US5841276A (en) * 1995-05-12 1998-11-24 Nippondenso Co., Ltd Magnetic gear rotation sensor
US6198276B1 (en) * 1997-02-19 2001-03-06 Nec Corporation Ferromagnetic-ball sensor using a magnetic field detection element

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4066962A (en) * 1976-12-08 1978-01-03 The Singer Company Metal detecting device with magnetically influenced Hall effect sensor
US5128613A (en) * 1985-02-25 1992-07-07 Kubota Ltd. Method of inspecting magnetic carburization in a non-permeable material and probe therefore
US5841276A (en) * 1995-05-12 1998-11-24 Nippondenso Co., Ltd Magnetic gear rotation sensor
US6198276B1 (en) * 1997-02-19 2001-03-06 Nec Corporation Ferromagnetic-ball sensor using a magnetic field detection element

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1759920A1 (fr) * 2005-08-31 2007-03-07 Hella KG Hueck & Co. Dispositif pour la détermination de la position nominale d'un projecteur pivotant d'automobile
DE102007030705B3 (de) * 2007-07-02 2009-02-05 Continental Automotive Gmbh Näherungsschalter
US20130055575A1 (en) * 2010-03-24 2013-03-07 Infaco Sas Device for controlling the relative positioning of two elements, such as the blades of secateur-type cutting tools, and a cutting tool comprising same

Also Published As

Publication number Publication date
DE112004001822D2 (de) 2006-08-31

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