EP1771703A1 - Irregular saturate pole position sensor - Google Patents

Irregular saturate pole position sensor

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Publication number
EP1771703A1
EP1771703A1 EP05793196A EP05793196A EP1771703A1 EP 1771703 A1 EP1771703 A1 EP 1771703A1 EP 05793196 A EP05793196 A EP 05793196A EP 05793196 A EP05793196 A EP 05793196A EP 1771703 A1 EP1771703 A1 EP 1771703A1
Authority
EP
European Patent Office
Prior art keywords
poles
pole
stabilization
irregular
position sensor
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Withdrawn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
EP05793196A
Other languages
German (de)
French (fr)
Inventor
Bertrand Legrand
Olivier Andrieu
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.)
EFI Automotive SA
Original Assignee
Electricfil Automotive SAS
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 Electricfil Automotive SAS filed Critical Electricfil Automotive SAS
Publication of EP1771703A1 publication Critical patent/EP1771703A1/en
Withdrawn legal-status Critical Current

Links

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
    • G01D5/25—Selecting one or more conductors or channels from a plurality of conductors or channels, e.g. by closing contacts
    • G01D5/252—Selecting one or more conductors or channels from a plurality of conductors or channels, e.g. by closing contacts a combination of conductors or channels
    • 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
    • G01D5/24428—Error prevention
    • G01D5/24433—Error prevention by mechanical means
    • G01D5/24438—Special design of the sensing element or scale
    • 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
    • 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
    • G01D5/25—Selecting one or more conductors or channels from a plurality of conductors or channels, e.g. by closing contacts

Definitions

  • the object of the invention relates to the technical field of magnetic sensors comprising an encoder element moving in the vicinity of a detection cell, and adapted to locate at least one angular position in the general sense.
  • the object of the invention relates more particularly to the production of a sensor whose encoder is equipped with a series of North poles and South poles mounted alternately.
  • the object of the invention finds a particularly advantageous application in the automotive field where this sensor can be used, for example, in the context of ignition functions.
  • a magnetic sensor adapted to measure the intensity change of a magnetic induction field when a ferromagnetic encoder provided with disturbing members of the field, scrolls in front of a detection cell.
  • the sensor cell such as a Hall effect or magnetoresistive probe, for example, delivers a periodic sinusoidal signal.
  • the detection cell is associated with a hysteresis level comparator, such as a Schmitt trigger, in order to obtain clear transitions of the output voltage for distinct values of the magnetic induction as it varies in increasing or decreasing.
  • a hysteresis level comparator such as a Schmitt trigger
  • patent FR 2 757 943 teaches the production of an encoder comprising, for each irregular pole, means for correcting the value of the magnetic field created. by the irregular pole, so that the signal delivered by the passage of neighboring poles to said irregular pole is symmetrical with respect to the zero value of the magnetic field.
  • US Pat. No. 4,866,381 describes a position sensor comprising an encoder provided on its circumference with alternating North and South poles and mounted to pass in front of a measuring cell.
  • Such an encoder comprises a magnetic singularity constituted by a series of North poles and South poles having a determined pitch adapted to stabilize the magnetic signal delivered by the passage of the poles adjacent to this singularity and within this singularity.
  • the ideal signal of this position sensor comprises, as the singularity passes, a succession of high and low states consecutive to the zero crossings of the magnetic signal corresponding to the different poles of the singularity.
  • the present invention aims at remedying the drawbacks of the prior art, by proposing a sensor having a simplicity and a good precision for the marking, in particular of the irregular pole, even for important variations of the measuring gap and the lateral offset between the rotation plane of the encoder and the axis of the measuring cell.
  • the position sensor of the type comprising an encoder formed by a multipolar magnetic ring provided, on its circumference, with alternating North and South poles and mounted to pass in front of a measuring cell delivering a periodic signal corresponding to the evolution of the intensity of the magnetic field delivered by the poles, at least one of said poles of a sign opposite to the sign of its adjacent poles is said to be "irregular" and comprises, on the one hand, between its two poles adjacent, a spacing different from the spacing pitch between the other poles and, secondly, means for correcting the value of its magnetic field, so as to stabilize the magnetic signal delivered by the passage of neighboring poles said irregular pole, said magnetic signal delivered between the passage of the adjacent poles not passing through the zero value.
  • the correction means are made by at least one saturated magnetic pole, called stabilization pole, having a sign opposite to the sign of the irregular pole which is also saturated, each stabilization pole extending from one edge to the other. the other of the magnetic ring, being interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole.
  • the irregular pole of opposite sign to the stabilization poles, comprises a series of elementary poles each extending from one edge to the other of the magnetic ring, between which are intercalated the stabilization poles.
  • the stabilization and elementary poles each have a constant width from one edge to the other of the magnetic ring.
  • the stabilization poles have an identical width.
  • all the stabilizing poles have a different width.
  • all the stabilizing poles and the elementary poles have an identical width.
  • all the stabilization poles have an identical width but different in value from the widths of the elementary poles.
  • the stabilization poles or poles are interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal, considered between the passage of an adjacent pole and the middle of the irregular pole, varies monotonously.
  • the stabilization poles or poles are interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal is symmetrical by compared to the null value of the magnetic field.
  • the stabilization pole or poles are inserted in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal has a period constant with regard to the poles adjacent to the irregular pole.
  • the stabilization pole or poles are inserted in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal has a symmetry relative to the middle of the irregular pole.
  • the measuring cell is a hall effect Hall effect Hall effect cell with flux concentrator, giant magnetoresistor.
  • the encoder is rotated on a shaft of an engine of a motor vehicle.
  • the fij. 1 is a general view showing an exemplary embodiment of a position sensor according to the invention.
  • the fg. 2 is a view, taken in a plane, of a first embodiment of an encoder according to the invention.
  • Fig. 3 is a curve illustrating the evolution of the magnetic induction obtained during the running of an encoder according to FIG. 2.
  • Fig. 1 shows an exemplary embodiment of a position sensor I comprising a magnetic encoder 1 mounted to pass in front of a detection cell 2.
  • the encoder 1 is constituted in the form of a multipolar magnetic ring, driven in rotation about its center , along an axis A parallel to the direction OX and provided, on its circumference, with North poles N and alternating South poles S, having a radial magnetization.
  • the encoder 1 comprises a series of South poles S and North poles N arranged to have a regular pitch spacing between two neighboring poles.
  • the angular width of each pole is 3 °.
  • the encoder 1 also comprises at least one so-called irregular pole Pi, having, between its two adjacent poles Pa, a different spacing with respect to the regular spacing pitch between the poles S and N.
  • the pole irregular Pi has an angular width of 15 ° and constitutes a North Pole, while adjacent poles Pa are of opposite signs, namely South.
  • the polarities of the adjacent poles Pa and the irregular pole Pi can be reversed.
  • the encoder 1 consists of a ring forming a support on which is adhered a ring made of elastomer charged with magnetized particles to form the North and South poles.
  • the encoder 1 comprises means 3 for correcting or compensating the value of the magnetic induction field created by the irregular pole Pi, with respect to the value of the induction field magnetic created by the neighboring poles, so as to stabilize the magnetic signal delivered by the cell 2 by the passage of neighboring poles to said irregular pole.
  • the means 3 can correct the value of the magnetic induction created by the irregular pole Pi, so that it does not disturb the inductions of neighboring poles.
  • the correction means 3 are determined so that the signal, corresponding to the change in the intensity of the magnetic field delivered by the neighboring poles to the irregular pole Pi, is not disturbed by the magnetic induction created by the pole.
  • Pi means 3 are therefore adapted to reduce the magnetic flux created by the irregular pole, while maintaining it at a value sufficient to allow its detection.
  • the correction means 3 are made by at least one and in the example illustrated in FIG. 2, four so-called stabilizing magnetic poles Ps having a sign opposite to the sign of the irregular pole Pi.
  • the irregular pole Pi is a North pole so that each stabilization pole Ps is a South pole.
  • the stabilization poles S are thus interposed in the irregular pole Pi so that the latter is formed by elementary poles Pe and the stabilization poles Ps.
  • each of the elementary poles Pe and the stabilization poles Ps have a substantially constant width from one edge to the other of the magnetic ring.
  • the stabilization poles Ps and the elementary poles Pe are saturated.
  • the constituent material of the stabilization poles Ps and elementary Pi is saturated, that is to say that the magnetization of the elementary poles or North in the illustrated example corresponds to the negative value of the magnetization maximum of the material while the magnetization of the stabilization poles or South in the illustrated example corresponds to the positive value of the maximum magnetization of the material.
  • the irregular pole Pi is insensitive to the neighboring magnetic zones which are able to modify the induction level in time and consequently the output signal of the detection system.
  • the irregular pole Pi according to the invention makes it possible to obtain a sensor that is durable over time.
  • the stabilization poles Ps are arranged in number and position so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole.
  • the stabilization pole or poles Ps are interposed in the irregular pole Pi, so as to stabilize the magnetic signal delivered by the passage of the adjacent poles Pa to the irregular pole Pi, so that such a signal includes one and / or the other of the characteristic described hereinafter.
  • the examination of fig. 3 makes it possible to highlight the interest of the implementation of the stabilization means 3.
  • FIG. 3 is a diagram showing the evolution of the magnetic induction field I in Gaxiss and more precisely of the component of the magnetic signal perpendicular to the surface of the encoder, as a function of the angular position of the encoder 1 with respect to a detection cell 2
  • Curve A shows the evolution of the magnetic induction I of an encoder devoid of the stabilization means 3 according to the invention
  • curve B shows the evolution of the magnetic induction I of an encoder 1. equipped with stabilization means 3 according to the invention.
  • the presence of the irregular pole Pi does not include stabilization means, influences the magnetic induction field of neighboring poles.
  • the curve A reveals two zones J corresponding to the passages of the adjacent poles Pa and each comprising a maximum followed by a decrease.
  • the presence of such zones J prohibits detection in differential mode.
  • the curve B which represents the component of the magnetic signal perpendicular to the surface of the encoder 2 in accordance with the invention makes it possible to observe that the constitution of the irregular pole Pi, as described above, makes it possible to remedy this drawback, in the extent to which such a signal, considered between the passage Ia of an adjacent pole Pa and the passage I M of the middle of the irregular pole Pi, varies monotonously, that is to say in one direction.
  • the magnetic signal does not pass through the magnetic zero or the zero value between the two passages Ia of the adjacent poles Pa.
  • the stabilization poles Ps incorporated in the irregular pole Pi therefore do not cause a passage through the zero value. , of the detected magnetic signal.
  • the stabilization means 3 according to the invention it thus appears, on the curve A, a drift amplitude and phase of the induction, which is even more accentuated than the regular pole is close to the irregular pole. This results in a phase shift in the induction signal.
  • Examination of the curve B makes it possible to observe that the magnetic induction created by the irregular pole Pi does not disturb the magnetic induction field of the adjacent regular poles.
  • the signal giving the change in the intensity of the magnetic field delivered by the adjacent regular poles to the irregular pole Pi is symmetrical with respect to the zero or zero value of the magnetic field.
  • Such a symmetry of the magnetic signal is obtained regardless of the width of the air gap, that is to say the distance between the detection cell 2 and the magnetic ring 1.
  • the signal I has a period constant T with respect to the regular poles adjacent to the irregular pole.
  • the stabilization pole or poles Ps are interposed in the irregular pole Pi, so as to stabilize the magnetic signal delivered by the passage of the adjacent poles Pa to the irregular pole Pi, so that such a signal has a symmetry with respect to at the passage I M of the middle of the irregular pole Pi.
  • the implementation of the stabilization means 3, as described above, makes it possible to obtain a good accuracy of the measurements made for the identification of the irregular pole Pi.
  • the magnetic induction created by the coder 1 can be detected by a sensitive cell 2 of all types, such as a Hall effect cell, Hall effect, Hall effect with a concentrator. flux, magnetoresistive, magneto-resistant giant (GMR).
  • a sensitive cell 2 of all types, such as a Hall effect cell, Hall effect, Hall effect with a concentrator. flux, magnetoresistive, magneto-resistant giant (GMR).
  • the irregular pole Pi consists of elementary stabilization poles distributed in the following manner: Pe, Ps, 2Pe, Ps, 5Pe, Ps, 2Pe, Ps, Pe.
  • the irregular pole Pi is constituted as follows: 3Pe, Ps, 7Pe, Ps, 3Pe.
  • Each stabilization pole Ps has a width of 0.5 °, while the elementary poles Pe together have an angular width of 14 °.
  • the encoder 1 according to the invention is intended to be mounted on a rotating target in the general sense, from which at least one position is determined.
  • the encoder 1 according to the invention is intended to be mounted on a drive pulley mounted at the output of the engine of a motor vehicle, that is to say on a distribution pulley or on one of the auxiliary pulleys.
  • the encoder 1 is mounted on the drive pulley located in the axis of the crankshaft, in order to allow detection of the top dead center of ignition of a cylinder.
  • the subject of the invention can also be applied to the production of a sensor comprising a magnetic ring 1 provided with a plurality of irregular poles Pi making it possible to locate several positions.
  • the magnetic ring 1 comprises, for example, four irregular poles Pi for locating the position of the cylinders of an engine.
  • the encoder 1 is mounted integral with the camshaft of a motor vehicle engine.
  • the encoder 1 can be mounted on the camshaft with only one irregular pole.
  • the encoder 1 according to the invention is intended to be mounted inside a support plate of a dynamic seal for a transmission shaft, mounted between the crankshaft and the gearbox of an engine of a motor vehicle.
  • the encoder 1 is rotated by the transmission shaft and is mounted in close relation with at least one detection cell 2 mounted on the support plate of the seal, to form a position sensor.
  • the encoder 1 according to the invention is rotated on a motor shaft of a motor vehicle or is rotated by the crankshaft or the camshaft of a motor vehicle. engine of a motor vehicle, being mounted inside the engine block of such a vehicle, in proximity relation of a sensor cell 2 to form a position sensor.

Abstract

The inventive position sensor is characterised in that it comprises correcting means (3) produced by at least one stabilising saturated magnetic pole (Ps) whose sign is opposite to the sign of an also saturated irregular pole (Pi), wherein each stabilising pole (Ps) extending from the one to the other edge of a magnetic ring is inserted into the irregular pole in such a way that it is possible to stabilise a magnetic signal provided by the passage of adjacent poles to the irregular pole and said magnetic signal provided between the passage of the adjacent poles does not pass thorough a zero value.

Description

CAPTEUR DE POSITION A POLE IRREGULIER SATURE POSITION SENSOR WITH IRREGULAR SATURATED POLE
L'objet de l'invention concerne le domaine technique des capteurs magnétiques comportant un élément codeur se déplaçant à proximité d'une cellule de détection, et adaptés pour repérer au moins une position angulaire au sens général. L'objet de l'invention concerne plus particulièrement, la réalisation d'un capteur dont le codeur est équipé d'une série de pôles Nord et pôles Sud montés de manière alternée.The object of the invention relates to the technical field of magnetic sensors comprising an encoder element moving in the vicinity of a detection cell, and adapted to locate at least one angular position in the general sense. The object of the invention relates more particularly to the production of a sensor whose encoder is equipped with a series of North poles and South poles mounted alternately.
L'objet de l'invention trouve une application particulièrement avantageuse dans le domaine automobile où ce capteur peut être utilisé, par exemple, dans le cadre des fonctions d'allumage.The object of the invention finds a particularly advantageous application in the automotive field where this sensor can be used, for example, in the context of ignition functions.
Il est connu, dans le domaine préféré ci-dessus, de mettre en œuvre un capteur magnétique adapté pour mesurer le changement d'intensité d'un champ d'induction magnétique lorsqu'un codeur ferromagnétique muni d'organes perturbateurs du champ, défile devant une cellule de détection. La cellule de détection telle qu'une sonde à effet Hall ou magnétorésistive, par exemple, délivre un signal sinusoïdal périodique. La cellule de détection est associée à un comparateur de niveau à hystérésis, tel qu'un trigger de Schmitt, afin d'obtenir des transitions franches de la tension de sortie pour des valeurs distinctes de l'induction magnétique selon qu'elle varie en croissant ou en décroissant. Afin de constituer un capteur de détection d'une vitesse, il est connu de réaliser un codeur pourvu de dents aménagées de manière régulière et en nombre élevé pour améliorer la résolution d'un tel capteur. Il est connu un perfectionnement à ce capteur consistant à réaliser un codeur constitué par un anneau magnétique multipolaire pourvu, sur sa circonférence, de pôles Nord et de pôles Sud alternés et régulièrement espacés selon un pas donné.It is known, in the field preferred above, to implement a magnetic sensor adapted to measure the intensity change of a magnetic induction field when a ferromagnetic encoder provided with disturbing members of the field, scrolls in front of a detection cell. The sensor cell such as a Hall effect or magnetoresistive probe, for example, delivers a periodic sinusoidal signal. The detection cell is associated with a hysteresis level comparator, such as a Schmitt trigger, in order to obtain clear transitions of the output voltage for distinct values of the magnetic induction as it varies in increasing or decreasing. In order to constitute a sensor for detecting a speed, it is known to produce an encoder provided with teeth arranged regularly and in large numbers to improve the resolution of such a sensor. It is known an improvement to this sensor consisting in producing an encoder consisting of a multipole magnetic ring provided, on its circumference, North poles and South poles alternated and evenly spaced at a given pitch.
Pour permettre de déterminer au moins une position, correspondant par exemple au point mort haut d'allumage d'un cylindre, il est connu de réaliser un repère sur le codeur magnétique. Il est connu ainsi de supprimer, par exemple, deux dents sur la roue dentée. Dans la solution mettant en œuvre un codeur pourvu de pôles Nord et pôles Sud alternés, il peut être envisagé, soit de supprimer plusieurs pôles magnétiques en laissant subsister un espace vide, soit de remplacer un ou plusieurs pôles d'un signe donné par un ou plusieurs pôles d'un signe contraire. Il est ainsi réalisé un pôle dit irrégulier ou singulier, présentant d'une part une aimantation d'un signe opposé au signe de ses deux pôles adjacents, et d'autre part, un écartement différent par rapport au pas d'écartement des autres pôles.In order to make it possible to determine at least one position, corresponding, for example, to the top dead center of a cylinder, it is known to make a mark on the magnetic encoder. It is known to remove, for example, two teeth on the toothed wheel. In the solution implementing an encoder provided with alternating North and South poles, it may be envisaged either to eliminate several magnetic poles while leaving a void space, or to replace one or more poles of a given sign by one or more poles. several poles of a contrary sign. It is thus realized a pole said irregular or singular, presenting on the one hand a magnetization of a sign opposite to the sign of its two adjacent poles, and secondly, a different spacing from the spacing pitch of the other poles.
Afin d'obtenir une bonne précision de mesure, notamment en ce qui concerne la détection du pôle irrégulier, le brevet FR 2 757 943 enseigne de réaliser un codeur comprenant, pour chaque pôle irrégulier, des moyens de correction de la valeur du champ magnétique créé par le pôle irrégulier, de manière que le signal délivré par le passage des pôles voisins audit pôle irrégulier, soit symétrique par rapport à la valeur nulle du champ magnétique.In order to obtain good measurement accuracy, particularly with regard to the detection of the irregular pole, patent FR 2 757 943 teaches the production of an encoder comprising, for each irregular pole, means for correcting the value of the magnetic field created. by the irregular pole, so that the signal delivered by the passage of neighboring poles to said irregular pole is symmetrical with respect to the zero value of the magnetic field.
La mise en œuvre d'un tel codeur permet d'obtenir en sortie de la cellule de détection du capteur, un signal magnétique dont la période est constante pour ce qui concerne les pôles réguliers. Il en résulte une bonne précision des mesures ainsi réalisées, notamment pour le repérage du pôle irrégulier.The implementation of such an encoder makes it possible to obtain at the output of the sensor detection cell a magnetic signal whose period is constant with respect to the regular poles. This results in a good accuracy of the measurements thus made, especially for the identification of the irregular pole.
Si la solution technique décrite dans ce brevet donne satisfaction en pratique, il a été constaté, dans certaines conditions d'exploitation, d'une part, une variation dans une plage importante de la largeur de l'entrefer délimité entre le codeur et la cellule de mesure et, d'autre part, un décalage latéral non négligeable, entre le plan de rotation du codeur et l'axe de la cellule de mesure, ce qui nuit à la précision des mesures.If the technical solution described in this patent is satisfactory in practice, it has been found, under certain operating conditions, on the one hand, a variation in a large range of the width of the air gap delimited between the encoder and the cell of measurement and, secondly, a significant lateral shift, between the rotational plane of the encoder and the axis of the measuring cell, which affects the accuracy of measurements.
De même, le brevet US 4 866 381 décrit un capteur de position comportant un codeur pourvu sur sa circonférence de pôles Nord et de pôles Sud alternés et montés pour défiler devant une cellule de mesure. Un tel codeur comporte une singularité magnétique constituée par une série de pôles Nord et de pôles Sud présentant un pas déterminé adapté pour stabiliser le signal magnétique délivré par le passage des pôles adjacents à cette singularité et à l'intérieur de cette singularité. Le signal idéal de ce capteur de position comporte au passage de la singularité, une succession d'états hauts et bas consécutifs aux passages par zéro du signal magnétique correspondants aux différents pôles de la singularité.Similarly, US Pat. No. 4,866,381 describes a position sensor comprising an encoder provided on its circumference with alternating North and South poles and mounted to pass in front of a measuring cell. Such an encoder comprises a magnetic singularity constituted by a series of North poles and South poles having a determined pitch adapted to stabilize the magnetic signal delivered by the passage of the poles adjacent to this singularity and within this singularity. The ideal signal of this position sensor comprises, as the singularity passes, a succession of high and low states consecutive to the zero crossings of the magnetic signal corresponding to the different poles of the singularity.
La présente invention vise à remédier aux inconvénients de la technique antérieure, en proposant un capteur présentant une simplicité et une bonne précision pour le repérage, notamment du pôle irrégulier, même pour des variations importantes de l'entrefer de mesure et du décalage latéral entre le plan de rotation du codeur et l'axe de la cellule de mesure. Pour atteindre de tels objectifs, le capteur de position du type comportant un codeur formé par un anneau magnétique multipolaire pourvu, sur sa circonférence, de pôles Nord et de pôles Sud alternés et monté pour défiler devant une cellule de mesure délivrant un signal périodique correspondant à l'évolution de l'intensité du champ magnétique délivré par les pôles, au moins l'un desdits pôles d'un signe contraire au signe de ses pôles adjacents est dit "irrégulier" et comporte, d'une part, entre ses deux pôles adjacents, un écartement différent par rapport au pas d'écartement entre les autres pôles et, d'autre part, des moyens de correction de la valeur de son champ magnétique, de manière à stabiliser le signal magnétique délivré, par le passage des pôles voisins audit pôle irrégulier, ledit signal magnétique délivré entre le passage des pôles adjacents ne passant pas par la valeur nulle.The present invention aims at remedying the drawbacks of the prior art, by proposing a sensor having a simplicity and a good precision for the marking, in particular of the irregular pole, even for important variations of the measuring gap and the lateral offset between the rotation plane of the encoder and the axis of the measuring cell. To achieve such objectives, the position sensor of the type comprising an encoder formed by a multipolar magnetic ring provided, on its circumference, with alternating North and South poles and mounted to pass in front of a measuring cell delivering a periodic signal corresponding to the evolution of the intensity of the magnetic field delivered by the poles, at least one of said poles of a sign opposite to the sign of its adjacent poles is said to be "irregular" and comprises, on the one hand, between its two poles adjacent, a spacing different from the spacing pitch between the other poles and, secondly, means for correcting the value of its magnetic field, so as to stabilize the magnetic signal delivered by the passage of neighboring poles said irregular pole, said magnetic signal delivered between the passage of the adjacent poles not passing through the zero value.
Conformément à l'invention, les moyens de correction sont réalisés par au moins un pôle magnétique saturé, dit de stabilisation, possédant un signe contraire au signe du pôle irrégulier qui est également saturé, chaque pôle de stabilisation s'étendant d'un bord à l'autre de l'anneau magnétique, en étant intercalé dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier.According to the invention, the correction means are made by at least one saturated magnetic pole, called stabilization pole, having a sign opposite to the sign of the irregular pole which is also saturated, each stabilization pole extending from one edge to the other. the other of the magnetic ring, being interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole.
Tel que cela ressort de l'invention, le pôle irrégulier, de signe contraire aux pôles de stabilisation, comporte une série de pôles élémentaires s'étendant chacun d'un bord à l'autre de l'anneau magnétique, entre lesquels sont intercalés les pôles de stabilisation.As is apparent from the invention, the irregular pole, of opposite sign to the stabilization poles, comprises a series of elementary poles each extending from one edge to the other of the magnetic ring, between which are intercalated the stabilization poles.
Avantageusement, les pôles de stabilisation et élémentaires présentent chacun une largeur constante d'un bord à l'autre de l'anneau magnétique.Advantageously, the stabilization and elementary poles each have a constant width from one edge to the other of the magnetic ring.
Selon un exemple de réalisation, les pôles de stabilisation possèdent une largeur identique.According to an exemplary embodiment, the stabilization poles have an identical width.
Selon une autre variante de réalisation, tous les pôles de stabilisation possèdent une largeur différente.According to another variant embodiment, all the stabilizing poles have a different width.
Selon encore une autre forme de réalisation, tous les pôles de stabilisation et les pôles élémentaires possèdent une largeur identique. Selon une autre variante de réalisation, tous les pôles de stabilisation possèdent une largeur identique mais de valeur différente des largeurs des pôles élémentaires.According to yet another embodiment, all the stabilizing poles and the elementary poles have an identical width. According to another variant embodiment, all the stabilization poles have an identical width but different in value from the widths of the elementary poles.
Selon une caractéristique de l'invention, la largeur totale des pôles de stabilisation est inférieure à la largeur totale des pôles élémentaires. Selon une autre caractéristique de l'invention, les pôles Nord et les pôles Sud alternés sont des pôles magnétiques saturés.According to one characteristic of the invention, the total width of the stabilization poles is less than the total width of the elementary poles. According to another characteristic of the invention, the alternating north and south poles are saturated magnetic poles.
Selon un aspect de l'invention, le ou les pôles de stabilisation sont intercalés dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal, considéré entre le passage d'un pôle adjacent et le milieu du pôle irrégulier, varie de manière monotone.According to one aspect of the invention, the stabilization poles or poles are interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal, considered between the passage of an adjacent pole and the middle of the irregular pole, varies monotonously.
Selon un autre aspect de l'invention, le ou les pôles de stabilisation sont intercalés dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal soit symétrique par rapport à la valeur nulle du champ magnétique.According to another aspect of the invention, the stabilization poles or poles are interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal is symmetrical by compared to the null value of the magnetic field.
Selon un autre aspect de l'invention, le ou les pôles de stabilisation sont intercalés dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal présente une période constante en ce qui concerne les pôles adjacents au pôle irrégulier.According to another aspect of the invention, the stabilization pole or poles are inserted in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal has a period constant with regard to the poles adjacent to the irregular pole.
Selon un autre aspect de l'invention, le ou les pôles de stabilisation sont intercalés dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal présente une symétrie par rapport au milieu du pôle irrégulier.According to another aspect of the invention, the stabilization pole or poles are inserted in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal has a symmetry relative to the middle of the irregular pole.
De manière avantageuse, la cellule de mesure est une cellule à effet Hall, à effet Hall différentielle, à effet Hall avec concentrateur de flux, magnétoristante géante.Advantageously, the measuring cell is a hall effect Hall effect Hall effect cell with flux concentrator, giant magnetoresistor.
Dans une application privilégiée du capteur selon l'invention, le codeur est calé en rotation sur un arbre d'un moteur d'un véhicule automobile.In a preferred application of the sensor according to the invention, the encoder is rotated on a shaft of an engine of a motor vehicle.
Diverses autres caractéristiques ressortent de la description faite ci-dessous en référence aux dessins annexés qui montrent, à titre d'exemples non limitatifs, des formes de réalisation et de mise en œuvre de l'objet de l'invention.Various other characteristics appear from the description given below with reference to the accompanying drawings which show, by way of non-limiting examples, embodiments and implementation of the subject of the invention.
La fïg. 1 est une vue générale montrant un exemple de réalisation d'un capteur de position selon l'invention.The fij. 1 is a general view showing an exemplary embodiment of a position sensor according to the invention.
La fîg. 2 est une vue, ramenée dans un plan, d'un premier exemple de réalisation d'un codeur conforme à l'invention. La fig. 3 est une courbe illustrant l'évolution de l'induction magnétique obtenue lors du défilement d'un codeur conforme à la fig. 2.The fg. 2 is a view, taken in a plane, of a first embodiment of an encoder according to the invention. Fig. 3 is a curve illustrating the evolution of the magnetic induction obtained during the running of an encoder according to FIG. 2.
La fig. 1 montre un exemple de réalisation d'un capteur de position I comportant un codeur magnétique 1 monté pour défiler devant une cellule de détection 2. Le codeur 1 est constitué sous la forme d'un anneau magnétique multipolaire, entraîné en rotation autour de son centre, selon un axe A parallèle à la direction OX et pourvu, sur sa circonférence, de pôles Nord N et de pôles Sud S alternés, présentant une aimantation radiale. Dans l'exemple illustré, le codeur 1 comporte une série de pôles Sud S et de pôles Nord N aménagés pour présenter un pas régulier d'écartement entre deux pôles voisins. Par exemple, la largeur angulaire de chaque pôle est de 3°. Conformément à l'invention et tel que cela ressort plus précisément de la fig. 2, le codeur 1 comporte aussi au moins un pôle dit irrégulier Pi, présentant, entre ses deux pôles adjacents Pa, un écartement différent par rapport au pas régulier d'écartement entre les pôles S et N. Dans l'exemple illustré, le pôle irrégulier Pi possède une largeur angulaire de 15° et constitue un pôle Nord, tandis que les pôles adjacents Pa sont de signes contraires, à savoir Sud. Bien entendu, les polarités des pôles adjacents Pa et du pôle irrégulier Pi peuvent être inversées. Par exemple, le codeur 1 est constitué par une couronne formant un support sur laquelle est adhérisée une bague réalisée en élastomère chargée de particules magnétisées pour constituer les pôles Nord et Sud.Fig. 1 shows an exemplary embodiment of a position sensor I comprising a magnetic encoder 1 mounted to pass in front of a detection cell 2. The encoder 1 is constituted in the form of a multipolar magnetic ring, driven in rotation about its center , along an axis A parallel to the direction OX and provided, on its circumference, with North poles N and alternating South poles S, having a radial magnetization. In the illustrated example, the encoder 1 comprises a series of South poles S and North poles N arranged to have a regular pitch spacing between two neighboring poles. For example, the angular width of each pole is 3 °. In accordance with the invention and as is more particularly apparent from FIG. 2, the encoder 1 also comprises at least one so-called irregular pole Pi, having, between its two adjacent poles Pa, a different spacing with respect to the regular spacing pitch between the poles S and N. In the illustrated example, the pole irregular Pi has an angular width of 15 ° and constitutes a North Pole, while adjacent poles Pa are of opposite signs, namely South. Of course, the polarities of the adjacent poles Pa and the irregular pole Pi can be reversed. For example, the encoder 1 consists of a ring forming a support on which is adhered a ring made of elastomer charged with magnetized particles to form the North and South poles.
Conformément à l'invention, pour chaque pôle irrégulier Pi, le codeur 1 comporte des moyens 3 de correction ou de compensation de la valeur du champ d'induction magnétique créé par le pôle irrégulier Pi, par rapport à la valeur du champ d'induction magnétique créé par les pôles voisins, de manière à stabiliser le signal magnétique délivré par la cellule 2 par le passage des pôles voisins audit pôle irrégulier. Comme cela sera décrit dans la suite de la description, les moyens 3 permettent de corriger la valeur de l'induction magnétique créée par le pôle irrégulier Pi, de sorte qu'elle ne perturbe pas les inductions des pôles voisins. Ainsi, les moyens de correction 3 sont déterminés de manière que le signal, correspondant à l'évolution de l'intensité du champ magnétique délivré par les pôles voisins au pôle irrégulier Pi, ne soit pas perturbé par l'induction magnétique créée par le pôle irrégulier Pi. Les moyens 3 sont donc adaptés de façon à diminuer le flux magnétique créé par le pôle irrégulier, tout en le maintenant à une valeur suffisante pour permettre sa détection.According to the invention, for each irregular pole Pi, the encoder 1 comprises means 3 for correcting or compensating the value of the magnetic induction field created by the irregular pole Pi, with respect to the value of the induction field magnetic created by the neighboring poles, so as to stabilize the magnetic signal delivered by the cell 2 by the passage of neighboring poles to said irregular pole. As will be described in the following description, the means 3 can correct the value of the magnetic induction created by the irregular pole Pi, so that it does not disturb the inductions of neighboring poles. Thus, the correction means 3 are determined so that the signal, corresponding to the change in the intensity of the magnetic field delivered by the neighboring poles to the irregular pole Pi, is not disturbed by the magnetic induction created by the pole. Pi means 3 are therefore adapted to reduce the magnetic flux created by the irregular pole, while maintaining it at a value sufficient to allow its detection.
Conformément à l'invention, les moyens de correction 3 sont réalisés par au moins un et dans l'exemple illustré à la fig. 2, quatre pôles magnétiques dits de stabilisation Ps possédant un signe contraire au signe du pôle irrégulier Pi. Dans l'exemple illustré, le pôle irrégulier Pi est un pôle Nord de sorte que chaque pôle de stabilisation Ps est un pôle Sud. Les pôles de stabilisation S sont ainsi intercalés dans le pôle irrégulier Pi de sorte que ce dernier se trouve formé par des pôles élémentaires Pe et les pôles de stabilisation Ps. Conformément à l'invention, les pôles élémentaires Pe et les pôles de stabilisation Ps s'étendent chacun d'un bord à l'autre de l'anneau magnétique. Avantageusement, chacun des pôles élémentaires Pe et des pôles de stabilisation Ps possèdent une largeur sensiblement constante d'un bord à l'autre de l'anneau magnétique. Selon une autre caractéristique de l'invention, les pôles de stabilisation Ps et les pôles élémentaires Pe sont saturés. En d'autres termes, le matériau constitutif des pôles de stabilisation Ps et élémentaires Pi est saturé, c'est-à-dire que l'aimantation des pôles élémentaires ou Nord dans l'exemple illustré correspond à la valeur négative de l'aimantation maximum du matériau tandis que l'aimantation des pôles de stabilisation ou Sud dans l'exemple illustré correspond à la valeur positive de l'aimantation maximum du matériau.According to the invention, the correction means 3 are made by at least one and in the example illustrated in FIG. 2, four so-called stabilizing magnetic poles Ps having a sign opposite to the sign of the irregular pole Pi. In the example illustrated, the irregular pole Pi is a North pole so that each stabilization pole Ps is a South pole. The stabilization poles S are thus interposed in the irregular pole Pi so that the latter is formed by elementary poles Pe and the stabilization poles Ps. In accordance with the invention, the elementary poles Pe and the stabilization poles Ps 'extend each from one edge to the other of the magnetic ring. Advantageously, each of the elementary poles Pe and the stabilization poles Ps have a substantially constant width from one edge to the other of the magnetic ring. According to another characteristic of the invention, the stabilization poles Ps and the elementary poles Pe are saturated. In other words, the constituent material of the stabilization poles Ps and elementary Pi is saturated, that is to say that the magnetization of the elementary poles or North in the illustrated example corresponds to the negative value of the magnetization maximum of the material while the magnetization of the stabilization poles or South in the illustrated example corresponds to the positive value of the maximum magnetization of the material.
Dans la mesure où les pôles de stabilisation Ps et les pôles élémentaires Pe sont saturés, le pôle irrégulier Pi est peu sensible aux zones magnétiques voisines qui sont à même de modifier dans le temps le niveau d'induction et par suite le signal de sortie du système de détection. Le pôle irrégulier Pi selon l'invention permet d'obtenir un capteur durable dans le temps.Insofar as the stabilization poles Ps and the elementary poles Pe are saturated, the irregular pole Pi is insensitive to the neighboring magnetic zones which are able to modify the induction level in time and consequently the output signal of the detection system. The irregular pole Pi according to the invention makes it possible to obtain a sensor that is durable over time.
Il doit être considéré que les pôles de stabilisation Ps sont disposés en nombre et en position de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier. En d'autres termes, le ou les pôles de stabilisation Ps sont intercalés dans le pôle irrégulier Pi, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents Pa au pôle irrégulier Pi, de sorte qu'un tel signal comporte l'une et/ou l'autre de la caractéristique décrite ci- après. L'examen de la fig. 3 permet de mettre en évidence l'intérêt de la mise en œuvre des moyens de stabilisation 3. La fig. 3 est un schéma montrant l'évolution du champ d'induction magnétique I en Gaxiss et plus précisément de la composante du signal magnétique perpendiculaire à la surface du codeur, en fonction de la position angulaire du codeur 1 par rapport à une cellule de détection 2. La courbe A montre l'évolution de l'induction magnétique I d'un codeur dépourvu des moyens de stabilisation 3 conformes à l'invention, tandis que la courbe B montre l'évolution de l'induction magnétique I d'un codeur 1 équipé des moyens de stabilisation 3 selon l'invention. Tel que cela ressort de cette figure, la présence du pôle irrégulier Pi ne comportant pas de moyens de stabilisation, influence le champ d'induction magnétique des pôles voisins.It must be considered that the stabilization poles Ps are arranged in number and position so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole. In other words, the stabilization pole or poles Ps are interposed in the irregular pole Pi, so as to stabilize the magnetic signal delivered by the passage of the adjacent poles Pa to the irregular pole Pi, so that such a signal includes one and / or the other of the characteristic described hereinafter. The examination of fig. 3 makes it possible to highlight the interest of the implementation of the stabilization means 3. FIG. 3 is a diagram showing the evolution of the magnetic induction field I in Gaxiss and more precisely of the component of the magnetic signal perpendicular to the surface of the encoder, as a function of the angular position of the encoder 1 with respect to a detection cell 2 Curve A shows the evolution of the magnetic induction I of an encoder devoid of the stabilization means 3 according to the invention, while curve B shows the evolution of the magnetic induction I of an encoder 1. equipped with stabilization means 3 according to the invention. As is apparent from this figure, the presence of the irregular pole Pi does not include stabilization means, influences the magnetic induction field of neighboring poles.
Ainsi, tel que cela ressort de la fig. 3, la courbe A laisse apparaître deux zones J correspondant aux passages des pôles adjacents Pa et comportant chacune, un maximum suivi d'une décroissance. La présence de telles zones J interdit une détection en mode différentiel. Or la courbe B qui représente la composante du signal magnétique perpendiculaire à la surface du codeur 2 conforme à l'invention, permet de constater que la constitution du pôle irrégulier Pi, telle que décrite ci-dessus, permet de remédier à cet inconvénient, dans la mesure où un tel signal, considéré entre le passage Ia d'un pôle adjacent Pa et le passage IM du milieu du pôle irrégulier Pi, varie de manière monotone, c'est-à-dire dans un seul sens. Il ressort donc que le signal magnétique ne passe pas par le zéro magnétique ou la valeur nulle entre les deux passages Ia des pôles adjacents Pa. Les pôles de stabilisation Ps incorporés dans le pôle irrégulier Pi n'entraînent donc pas un passage par la valeur nulle, du signal magnétique détecté. Par ailleurs, en l'absence des moyens de stabilisation 3 conformes à l'invention, il apparaît ainsi, sur la courbe A, une dérive en amplitude et en phase de l'induction, qui est d'autant plus accentuée que le pôle régulier est proche du pôle irrégulier. Il s'ensuit un déphasage dans le signal d'induction. L'examen de la courbe B permet de constater que l'induction magnétique créée par le pôle irrégulier Pi ne vient pas perturber le champ d'induction magnétique des pôles réguliers voisins. Le signal donnant le changement de l'intensité du champ magnétique délivré par les pôles réguliers voisins au pôle irrégulier Pi, est symétrique par rapport à la valeur zéro ou nulle du champ magnétique. Une telle symétrie du signal magnétique est obtenue quelle que soit la largeur de l'entrefer, c'est-à-dire de la distance entre la cellule de détection 2 et l'anneau magnétique 1. Il s'avère que le signal I présente une période constante T en ce qui concerne les pôles réguliers voisins du pôle irrégulier. Par ailleurs, le ou les pôles de stabilisation Ps sont intercalés dans le pôle irrégulier Pi, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents Pa au pôle irrégulier Pi, de sorte qu'un tel signal présente une symétrie par rapport au passage IM du milieu du pôle irrégulier Pi.Thus, as is apparent from FIG. 3, the curve A reveals two zones J corresponding to the passages of the adjacent poles Pa and each comprising a maximum followed by a decrease. The presence of such zones J prohibits detection in differential mode. Now the curve B which represents the component of the magnetic signal perpendicular to the surface of the encoder 2 in accordance with the invention makes it possible to observe that the constitution of the irregular pole Pi, as described above, makes it possible to remedy this drawback, in the extent to which such a signal, considered between the passage Ia of an adjacent pole Pa and the passage I M of the middle of the irregular pole Pi, varies monotonously, that is to say in one direction. It therefore emerges that the magnetic signal does not pass through the magnetic zero or the zero value between the two passages Ia of the adjacent poles Pa. The stabilization poles Ps incorporated in the irregular pole Pi therefore do not cause a passage through the zero value. , of the detected magnetic signal. Furthermore, in the absence of the stabilization means 3 according to the invention, it thus appears, on the curve A, a drift amplitude and phase of the induction, which is even more accentuated than the regular pole is close to the irregular pole. This results in a phase shift in the induction signal. Examination of the curve B makes it possible to observe that the magnetic induction created by the irregular pole Pi does not disturb the magnetic induction field of the adjacent regular poles. The signal giving the change in the intensity of the magnetic field delivered by the adjacent regular poles to the irregular pole Pi, is symmetrical with respect to the zero or zero value of the magnetic field. Such a symmetry of the magnetic signal is obtained regardless of the width of the air gap, that is to say the distance between the detection cell 2 and the magnetic ring 1. It turns out that the signal I has a period constant T with respect to the regular poles adjacent to the irregular pole. Moreover, the stabilization pole or poles Ps are interposed in the irregular pole Pi, so as to stabilize the magnetic signal delivered by the passage of the adjacent poles Pa to the irregular pole Pi, so that such a signal has a symmetry with respect to at the passage I M of the middle of the irregular pole Pi.
La mise en œuvre des moyens de stabilisation 3, tels que décrits ci-dessus, permet d'obtenir une bonne précision des mesures réalisées pour le repérage du pôle irrégulier Pi.The implementation of the stabilization means 3, as described above, makes it possible to obtain a good accuracy of the measurements made for the identification of the irregular pole Pi.
Selon une caractéristique avantageuse de l'invention, l'induction magnétique créée par le codeur 1 peut être décelée par une cellule sensible 2 de tous types, tels qu'une cellule à effet Hall, à effet Hall différentielle, à effet Hall avec concentrateur de flux, magnétorésistive, magnétorésistante géante (GMR).According to an advantageous characteristic of the invention, the magnetic induction created by the coder 1 can be detected by a sensitive cell 2 of all types, such as a Hall effect cell, Hall effect, Hall effect with a concentrator. flux, magnetoresistive, magneto-resistant giant (GMR).
Il doit être considéré que l'ordre et le nombre des pôles élémentaires Pe et de stabilisation Ps, ainsi que la largeur de chacun d'eux, sont variables en fonction de l'application visée et de la nature de la stabilisation ou de la correction choisie.It must be considered that the order and number of the elementary poles Pe and stabilization Ps, as well as the width of each of them, are variable according to the intended application and the nature of the stabilization or correction. chosen.
Selon l'exemple de réalisation illustré à la fig. 2, tous les pôles de stabilisation Ps et les pôles élémentaires Pe possèdent chacun une même largeur. Dans l'exemple illustré, chaque pôle de stabilisation Ps et élémentaire Pe possède une largeur égale à 1°. Selon cet exemple, le pôle irrégulier Pi est constitué par des pôles de stabilisation élémentaires distribués de la manière suivante : Pe, Ps, 2Pe, Ps, 5Pe, Ps, 2Pe, Ps, Pe. II peut être prévu un autre exemple de réalisation dans lequel tous les pôles de stabilisation Ps possèdent une largeur identique, mais de valeur différente des largeurs des pôles élémentaires Pe. Selon cet exemple, le pôle irrégulier Pi est constitué de la manière suivante : 3Pe, Ps, 7Pe, Ps, 3Pe. Chaque pôle de stabilisation Ps présente une largeur de 0,5°, tandis que les pôles élémentaires Pe présentent ensemble une largeur angulaire de 14°.According to the embodiment shown in FIG. 2, all the stabilization poles Ps and the elementary poles Pe each have the same width. In the illustrated example, each stabilization pole Ps and elementary Pe has a width equal to 1 °. According to this example, the irregular pole Pi consists of elementary stabilization poles distributed in the following manner: Pe, Ps, 2Pe, Ps, 5Pe, Ps, 2Pe, Ps, Pe. There may be provided another embodiment in which all the stabilization poles Ps have an identical width, but of different value than the widths of the elementary poles Pe. According to this example, the irregular pole Pi is constituted as follows: 3Pe, Ps, 7Pe, Ps, 3Pe. Each stabilization pole Ps has a width of 0.5 °, while the elementary poles Pe together have an angular width of 14 °.
Le codeur 1 selon l'invention, tel que décrit ci-dessus, est destiné à être monté sur une cible tournante au sens général, à partir de laquelle au moins une position est déterminée. Selon une caractéristique préférée de réalisation, le codeur 1 selon l'invention est destiné à être monté sur une poulie d'entraînement montée en sortie du moteur d'un véhicule automobile, c'est-à-dire sur une poulie de distribution ou sur l'une des poulies auxiliaires. Selon une caractéristique avantageuse, le codeur 1 est monté sur la poulie d'entraînement se trouvant dans l'axe du vilebrequin, afin de permettre une détection du point mort haut d'allumage d'un cylindre.The encoder 1 according to the invention, as described above, is intended to be mounted on a rotating target in the general sense, from which at least one position is determined. According to a preferred embodiment, the encoder 1 according to the invention is intended to be mounted on a drive pulley mounted at the output of the engine of a motor vehicle, that is to say on a distribution pulley or on one of the auxiliary pulleys. According to an advantageous characteristic, the encoder 1 is mounted on the drive pulley located in the axis of the crankshaft, in order to allow detection of the top dead center of ignition of a cylinder.
Il est à noter que l'objet de l'invention peut également être appliqué à la réalisation d'un capteur comportant un anneau magnétique 1 muni de plusieurs pôles irréguliers Pi permettant de repérer plusieurs positions. D'une manière avantageuse, l'anneau magnétique 1 comporte, par exemple, quatre pôles irréguliers Pi permettant de repérer la position des cylindres d'un moteur. Dans ce cas, le codeur 1 est monté solidaire de l'arbre à cames d'un moteur de véhicule automobile. Bien entendu, le codeur 1 peut être monté sur l'arbre à cames en ayant un seul pôle irrégulier.It should be noted that the subject of the invention can also be applied to the production of a sensor comprising a magnetic ring 1 provided with a plurality of irregular poles Pi making it possible to locate several positions. Advantageously, the magnetic ring 1 comprises, for example, four irregular poles Pi for locating the position of the cylinders of an engine. In this case, the encoder 1 is mounted integral with the camshaft of a motor vehicle engine. Of course, the encoder 1 can be mounted on the camshaft with only one irregular pole.
Selon une autre caractéristique préférée de mise en œuvre, le codeur 1 selon l'invention est destiné à être monté à l'intérieur d'une plaque de support d'un joint d'étanchéité dynamique pour un arbre de transmission, montée entre le vilebrequin et la boîte de vitesses d'un moteur d'un véhicule automobile. Le codeur 1 est entraîné en rotation par l'arbre de transmission et se trouve monté en relation de proximité d'au moins une cellule de détection 2 montée sur la plaque de support du joint d'étanchéité, afin de constituer un capteur de position. Selon une autre caractéristique préférée de mise en œuvre, le codeur 1 selon l'invention est calé en rotation sur un arbre d'un moteur d'un véhicule automobile ou est entraîné en rotation par le vilebrequin ou l'arbre à cames d'un moteur d'un véhicule automobile, en étant monté à l'intérieur du bloc moteur d'un tel véhicule, en relation de proximité d'une cellule de détection 2 afin de constituer un capteur de position.According to another preferred embodiment, the encoder 1 according to the invention is intended to be mounted inside a support plate of a dynamic seal for a transmission shaft, mounted between the crankshaft and the gearbox of an engine of a motor vehicle. The encoder 1 is rotated by the transmission shaft and is mounted in close relation with at least one detection cell 2 mounted on the support plate of the seal, to form a position sensor. According to another preferred embodiment, the encoder 1 according to the invention is rotated on a motor shaft of a motor vehicle or is rotated by the crankshaft or the camshaft of a motor vehicle. engine of a motor vehicle, being mounted inside the engine block of such a vehicle, in proximity relation of a sensor cell 2 to form a position sensor.
L'invention n'est pas limitée aux exemples décrits et représentés, car diverses modifications peuvent y être apportées sans sortir de son cadre. The invention is not limited to the examples described and shown, since various modifications can be made without departing from its scope.

Claims

REVENDICATIONS
1 - Capteur de position, du type comportant un codeur formé par un anneau magnétique multipolaire (1) pourvu, sur sa circonférence, de pôles Nord (N) et de pôles Sud (S) alternés et monté pour défiler devant une cellule de mesure (2) délivrant un signal périodique correspondant à l'évolution de l'intensité du champ magnétique délivré par les pôles, au moins l'un desdits pôles d'un signe contraire au signe de ses pôles adjacents (Pa) est dit "irrégulier" (Pi) et comporte, d'une part, entre ses deux pôles adjacents (Pa), un écartement différent par rapport au pas d'écartement entre les autres pôles et, d'autre part, des moyens (3) de correction de la valeur de son champ magnétique, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents audit pôle irrégulier, ledit signal magnétique délivré entre le passage des pôles adjacents ne passant pas par la valeur nulle, caractérisé en ce que les moyens de correction (3) sont réalisés par au moins un pôle magnétique saturé, dit de stabilisation (Ps), possédant un signe contraire au signe du pôle irrégulier (Pi) qui est également saturé, chaque pôle de stabilisation (Ps) s'étendant d'un bord à l'autre de l'anneau magnétique, en étant intercalé dans le pôle irrégulier, de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier.1 - Position sensor, of the type comprising an encoder formed by a multipole magnetic ring (1) provided, on its circumference, with alternating North (N) and South poles (S) and mounted to pass in front of a measuring cell ( 2) delivering a periodic signal corresponding to the evolution of the intensity of the magnetic field delivered by the poles, at least one of said poles of a sign opposite to the sign of its adjacent poles (Pa) is said to be "irregular" ( Pi) and comprises, on the one hand, between its two adjacent poles (Pa), a different spacing with respect to the spacing pitch between the other poles and, on the other hand, means (3) for correcting the value of its magnetic field, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to said irregular pole, said magnetic signal delivered between the passage of the adjacent poles not passing through the zero value, characterized in that the correction means ( 3) are made by at least one saturated magnetic pole, said stabilization (Ps), having a sign opposite the sign of the irregular pole (Pi) which is also saturated, each stabilization pole (Ps) extending from one edge to the other of the magnetic ring, being interposed in the irregular pole, so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole.
2 - Capteur de position selon la revendication 1, caractérisé en ce que le pôle irrégulier (Pi), de signe contraire aux pôles de stabilisation (Ps), comporte une série de pôles élémentaires (Pe) s'étendant chacun d'un bord à l'autre de l'anneau magnétique, entre lesquels sont intercalés les pôles de stabilisation (Ps).2 - Position sensor according to claim 1, characterized in that the irregular pole (Pi), of opposite sign to the stabilization poles (Ps), comprises a series of elementary poles (Pe) each extending from one edge to the other of the magnetic ring, between which are interposed the stabilization poles (Ps).
3 - Capteur de position selon la revendication 1 ou 2, caractérisé en ce que les pôles de stabilisation (Ps) et élémentaires (Pe) présentent chacun une largeur constante d'un bord à l'autre de l'anneau magnétique.3 - Position sensor according to claim 1 or 2, characterized in that the stabilization poles (Ps) and elementary (Pe) each have a constant width from one edge to the other of the magnetic ring.
4 - Capteur de position selon la revendication 3, caractérisé en ce que tous les pôles de stabilisation (Ps) possèdent une largeur identique.4 - Position sensor according to claim 3, characterized in that all the stabilization poles (Ps) have the same width.
5 - Capteur de position selon la revendication 3, caractérisé en ce que tous les pôles de stabilisation (Ps) possèdent une largeur différente. 6 - Capteur de position selon la revendication 3, caractérisé en ce que tous les pôles de stabilisation (Ps) et les pôles élémentaires (Pe) possèdent une largeur identique. 7 - Capteur de position selon la revendication 3, caractérisé en ce que tous les pôles de stabilisation (Ps) possèdent une largeur identique, mais de valeur différente des largeurs des pôles élémentaires (Pe).5 - position sensor according to claim 3, characterized in that all the stabilization poles (Ps) have a different width. 6 - Position sensor according to claim 3, characterized in that all the stabilization poles (Ps) and the elementary poles (Pe) have an identical width. 7 - Position sensor according to claim 3, characterized in that all the stabilization poles (Ps) have an identical width, but different value of the widths of the elementary poles (Pe).
8 - Capteur de position selon l'une des revendications 2 à 7, caractérisé en ce que la largeur totale des pôles de stabilisation (Ps) est inférieure à la largeur totale des pôles élémentaires (Pe).8 - position sensor according to one of claims 2 to 7, characterized in that the total width of the stabilization poles (Ps) is less than the total width of the elementary poles (Pe).
9 - Capteur de position selon la revendication 1 , caractérisé en ce que les pôles Nord (N) et les pôles Sud (S) alternés sont des pôles magnétiques saturés.9 - Position sensor according to claim 1, characterized in that the north poles (N) and the south poles (S) are alternating saturated magnetic poles.
10 - Capteur de position selon la revendication 1, caractérisé en ce que le ou les pôles de stabilisation (Ps) sont intercalés dans le pôle irrégulier (Pi) de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal, considéré entre le passage d'un pôle adjacent et le milieu du pôle irrégulier, varie de manière monotone.Position sensor according to claim 1, characterized in that the stabilizing pole or poles (Ps) are interposed in the irregular pole (Pi) so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal, considered between the passage of an adjacent pole and the middle of the irregular pole, varies monotonously.
11 - Capteur de position selon la revendication 1 ou 10, caractérisé en ce que le ou les pôles de stabilisation (Ps) sont intercalés dans le pôle irrégulier (Pi), de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal soit symétrique par rapport à la valeur nulle du champ magnétique.11 - Position sensor according to claim 1 or 10, characterized in that the stabilization pole or poles (Ps) are interposed in the irregular pole (Pi), so as to stabilize the magnetic signal delivered by the passage of poles adjacent to the irregular pole, so that such a signal is symmetrical with respect to the null value of the magnetic field.
12 - Capteur de position selon la revendication 1, 10 ou 11, caractérisé en ce que le ou les pôles de stabilisation (Ps) sont intercalés dans le pôle irrégulier (Pi), de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal présente une période constante en ce qui concerne les pôles adjacents au pôle irrégulier.12 - Position sensor according to claim 1, 10 or 11, characterized in that the stabilization pole or poles (Ps) are interposed in the irregular pole (Pi), so as to stabilize the magnetic signal delivered by the passage of the poles adjacent to the irregular pole, so that such a signal has a constant period with respect to the poles adjacent to the irregular pole.
13 - Capteur de position selon la revendication 1, 10, 11 ou 12, caractérisé en ce que le ou les pôles de stabilisation (Ps) sont intercalés dans le pôle irrégulier (Pi), de manière à stabiliser le signal magnétique délivré par le passage des pôles adjacents au pôle irrégulier, de sorte qu'un tel signal présente une symétrie par rapport au milieu du pôle irrégulier.13 - Position sensor according to claim 1, 10, 11 or 12, characterized in that the stabilization pole or poles (Ps) are interposed in the irregular pole (Pi), so as to stabilize the magnetic signal delivered by the passage poles adjacent to the irregular pole, so that such a signal has a symmetry with respect to the middle of the irregular pole.
14 - Capteur de position selon la revendication 1 , caractérisé en ce que la cellule de mesure (2) est une cellule à effet Hall, à effet Hall différentielle, à effet Hall avec concentrateur de flux, magnétorésistive, magnétorésistante géante. 15 - Capteur de position selon l'une des revendications 1 à 14, caractérisé en ce que le codeur (1) est calé en rotation sur un arbre d'un moteur d'un véhicule automobile. 14 - Position sensor according to claim 1, characterized in that the measuring cell (2) is a hall effect Hall effect cell, Hall effect with flux concentrator, magneto-resistive, magneto-resistant giant. 15 - Position sensor according to one of claims 1 to 14, characterized in that the encoder (1) is rotated on a motor shaft of a motor vehicle.
EP05793196A 2004-07-27 2005-07-27 Irregular saturate pole position sensor Withdrawn EP1771703A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR0408281A FR2873806B1 (en) 2004-07-27 2004-07-27 POSITION SENSOR WITH IRREGULAR POLE STATURE
PCT/FR2005/001963 WO2006018543A1 (en) 2004-07-27 2005-07-27 Irregular saturate pole position sensor

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KR (1) KR20070049647A (en)
BR (1) BRPI0513770A (en)
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WO (1) WO2006018543A1 (en)

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BRPI0513770A (en) 2008-05-20
FR2873806B1 (en) 2006-11-24
US7705587B2 (en) 2010-04-27

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