FR3080679A1 - DEVICE FOR DETECTING THE ANGULAR POSITION OF A ROTOR OF A ROTATING ELECTRIC MACHINE - Google Patents

Abstract

The invention relates to a device (500) for detecting the angular position of a rotor (4) of a rotating electrical machine (600) intended to set a motor vehicle in motion, the rotor (4) being rotatably mounted in a stator (5) of the rotating electrical machine (600). The device (500) for detecting the angular position of the rotor (4) comprises at least: at least one position sensor (2a, 2b, 2c) configured to be integral with the stator (5) of the rotating electrical machine (600) ), - a magnetic target (1) having magnetic poles North and South, the magnetic target (1) comprising a first face (10, 10a) and a second face (11, 11a), the magnetic target (1) being movable in rotation about an axis of revolution (100), configured to be centered on an axis of rotation (400) of the rotor (4), characterized in that a dimension (15) measured between the first face (10, 10a ) and the second face (11, 11a) is variable.

Description

DEVICE FOR DETECTING THE ANGULAR POSITION OF A ROTOR OF A ROTATING ELECTRIC MACHINE

The field of the present invention is that of rotating electrical machines used in motor vehicles. The invention relates more particularly to rotary electrical machines used in particular for setting in motion a motor vehicle.

Such a rotary electrical machine comprises at least one stator and a rotor placed within this stator and movable in rotation relative to the latter. In the context of using such a rotating electric machine as an electric motor, it is important to know precisely the angular position of the rotor relative to the stator, in particular for injecting electric current at the right time into the stator.

To do this, it is known to equip the rotary electrical machine with at least one rotor position sensor and a magnetic target, the position sensor being integral with the stator and the magnetic target being linked to the rotor.

The evolution of motor vehicles has led to the production of rotating electrical machines whose rotors have increasingly large diameters. This increase in the diameter of the rotors is accompanied by an increase in the mechanical stresses which apply to the production and the installation within such a rotary electrical machine of a position sensor of the rotor and of the target. associated magnetic. In addition, the increase in the diameter of the rotors is accompanied by significant changes in the electromagnetic signal detected by the position sensor, changes which should be limited when possible and / or taken into account for quality detection. the angular position of the rotor. These modifications to take into account relate on the one hand, to the amplitude of voltage of the signal which comes from the sensor and on the other hand, to the maximum acceptable level of harmonics for this signal.

The object of the invention is to propose an assembly for detecting the angular position of a large diameter rotor which is simple and inexpensive to manufacture and which is easy to install in a rotary electric machine intended to set a vehicle in motion. automotive, and which allows the generation of a quality signal illustrating the desired angular position.

To this end, the subject of the invention is a device for detecting the angular position of a rotor mounted mobile in rotation in a stator of a rotary electric machine intended to set in motion a motor vehicle, the device for detecting position angular of the rotor comprising at least:

- at least one position sensor, configured to be integral with the stator of the rotary electric machine,

a magnetic target comprising magnetic poles North and South, the magnetic target comprising a first face and a second face, the magnetic target being movable in rotation around an axis of revolution, configured to be centered on an axis of rotation of the rotor , characterized in that a dimension measured between the first face and the second face is variable.

In the device according to the invention, the position sensor is, for example, a sensor of the Hall effect type. Advantageously, the position detection assembly according to the invention comprises several position sensors, in particular of this type.

The magnetic target of the detection device according to the invention has a generally substantially cylindrical shape. More specifically, the magnetic target of the detection device according to the invention advantageously has, in a plane perpendicular to its axis of revolution, a substantially annular shape.

It should be understood here by substantially that the dimensions and orientations mentioned in this document take into account the manufacturing, mounting and wear tolerances.

To allow the detection of the desired angular position, the magnetic target has, within a rotary electrical machine equipped with a detection device according to the invention, a magnetic configuration representative of the magnetic configuration of the rotor to which it is linked.

Advantageously, the magnetic target of the device according to the invention therefore has a succession of North and South magnetic poles arranged alternately around its axis of revolution.

Advantageously, the magnetic target of the detection device according to the invention is received in a target holder which has an axis of revolution substantially coincident with the axis of revolution, previously defined, of the magnetic target, the target holder being movable in rotation around its axis of revolution. Within a rotary electric machine equipped with a detection device according to the invention, this axis is substantially coincident with the axis of rotation of the rotor of the rotary electric machine. More specifically, within such a rotating electrical machine, the target holder is advantageously linked to the aforementioned rotor, directly or by means of one or more parts, in such a way that it is, with the magnetic target that 'it carries, driven in rotation by the rotation of the rotor, about the axis of rotation of the latter. In other words, within a rotary electric machine equipped with a detection device according to the invention, the magnetic target is linked in rotation with the rotor of the rotary electric machine and coaxial with the latter.

The position sensor (s) are placed in such a way that when the magnetic target is rotated around its axis of revolution, all the angular regions of this magnetic target, measured around the axis of revolution of the latter, pass successively in front of this or these sensors. In other words, the position sensor (s) are, in the detection device according to the invention, in a fixed relative position relative to the magnetic target driven in rotation about its axis of revolution. In a rotary electric machine equipped with a detection assembly according to the invention, the position sensor (s) are advantageously linked to the stator of the rotary electric machine, directly or through one or more parts, in such a way that when the rotor of this rotary electric machine is driven in rotation about its axis of revolution, an annular surface of the magnetic target passes in front of this or these sensors.

It should be noted that the invention applies to all types of relative configurations of the magnetic target and of the position sensor or sensors within the detection device according to the invention, insofar as the position sensor or sensors are in a fixed relative position relative to the magnetic target when the latter is rotated about its axis of revolution.

Thus, according to a first configuration, designated in the following as an internal radial configuration, the target holder has, in section along a plane containing its axis of revolution, the general shape of a U, the axis of revolution of the holder. target being located in a substantially central position of the horizontal portion of this U. According to this internal radial configuration, the magnetic target is in the form of a portion of cylinder coaxial with the axis of revolution of the target holder and placed inside vertical branches of the aforementioned U. In this relative configuration, the position sensor (s) are placed between the magnetic target and the axis of revolution common to the latter and to the target holder. In other words, in this internal radial configuration, the position sensor (s) are arranged radially inside the substantially cylindrical volume defined by the magnetic target.

According to a second configuration, designated in the following as an external radial configuration, the target holder has, in section along a plane containing its axis of revolution, the same general shape as in the internal radial configuration, that is to say the general shape of a U, and the magnetic target is in the form of a portion of cylinder coaxial with the axis of revolution of the target holder. However, in the external radial configuration, the magnetic target is placed outside the vertical branches of the U previously described. In this relative configuration, the magnetic target is placed, radially with respect to its axis of revolution, between the vertical branches of the U formed by the target holder and the angular position detection sensors. In other words, in the external radial configuration, the position sensor (s) are arranged radially outside the substantially cylindrical volume defined by the magnetic target itself placed outside the receiving housing of the target holder .

It should be noted that, in the internal radial configuration or in the external radial configuration, the position sensor or sensors are placed facing an axial wall of the magnetic target, that is to say facing a wall extending parallel to the axis of revolution of the magnetic target.

According to a third configuration, designated in the following as an axial configuration, the target holder has, in section along a plane containing its axis of revolution, the same general shape as in the internal radial configuration and in the external radial configuration, it that is to say the general shape of a U, the axis of revolution of the target holder being placed substantially in the central position of the horizontal branch of this U. However, in the axial configuration, the magnetic target, of annular shape , is placed against the horizontal branch of the aforementioned U, inside the reception housing, previously defined, delimited by this U. In this axial configuration, the position sensor or sensors are placed facing an annular surface of the magnetic target, that is to say with regard to a surface of this target which is perpendicular to its axis of revolution.

According to different manufacturing methods, the magnetic target can be produced by injecting, into a mold, a polymer resin or an elastomeric material loaded with magnetic particles such as, for example, ferrite particles or rare earth particles. By way of nonlimiting examples, the polymeric material used to manufacture the magnetic target can be a resin based on polyamide or polyphenyl. More generally, the materials used to manufacture the magnetic target are advantageously chosen to meet the constraints of rigidity and resistance at high temperature imposed by the environment and by the operation of the rotating electric machine. According to different embodiments, the magnetic target can be injection molded or attached by bonding to a surface of the target holder.

According to the invention, the magnetic target comprises a first face and a second face which determine between them a variable dimension.

The aforementioned dimension is measured here

- in a plane perpendicular to the axis of revolution of the magnetic target, in a radial direction, in the case of radial configurations, or

- in a direction parallel to the axis of revolution of the magnetic target in the case of the axial configuration. In other words, this dimension can be measured perpendicular to a plane in which the face of the target fits which is devoid of the undulations generating the variation of the dimension between the first face and the second face.

This variable dimension can be called the thickness of the magnetic target. The thickness of the magnetic target varies, evolving circularly around the axis of revolution of the magnetic target.

Depending on the position of the sensor, the first face or the second face can be corrugated and this corrugated face is the one facing the sensor (s).

According to an exemplary embodiment, with reference to the axis of revolution of the magnetic target, the first face is an inner face of the magnetic target, while the second face is an outer face of the magnetic target. The inner face is, radially with respect to the previously defined axis of revolution, the wall of the magnetic target closest to this axis of revolution, and the outer face is, radially with respect to the previously defined axis of revolution, the wall of the magnetic target furthest from this axis of revolution.

The dimension previously cited is, with reference to these definitions, a radial dimension, measured radially with respect to the axis of revolution of the magnetic target, between the above-mentioned inner face and the outer face. In other words, the radial dimension here corresponds to a thickness, measured radially, of the annular shape which the magnetic target has in section along a plane perpendicular to its axis of revolution.

It must then be understood from the above that according to the invention, the distance measured between the first face and the second face of the magnetic target, is not constant over all the angular positions of an angular sector of 360 degrees , measured around the axis of revolution of the magnetic target and in a plane perpendicular to it. In other words, the distance between the first face and the second face of the ring formed by the magnetic target varies along the periphery of the magnetic target.

As mentioned above, to carry out the desired detection, the magnetic target is rotated around its axis of revolution. In this rotational movement, the signal detected by the position sensor (s) varies according to the magnetic configuration of the region of the magnetic target, driven in rotation around its axis of revolution, which passes over this or these sensor (s) of position. As such position sensors being, as indicated above, fixed relative to the moving magnetic target in rotation, it follows from the above that, during the rotation of the magnetic target, the distance between the latter and the or the position sensors vary. According to the invention, this variation in distance is configured to optimize the signal detected by the position sensor (s) in order to carry out, in a rotary electrical machine comprising a detection device according to the invention, a quality detection of the angular position of a large diameter rotor. A detection device according to the invention thus guarantees ease of manufacture and mounting on the rotating machine. It also guarantees compliance with the voltage amplitude values, thus avoiding any signal clipping phenomenon.

Advantageously, the invention may have one or more of the following characteristics, taken separately or in combination:

- The variation of the dimension of the magnetic target measured between the first face and the second face of the magnetic target is regular. It is understood here that this variation is continuous on the periphery of the latter, for the radial configurations, or on an annular surface of the magnetic target, for the axial configuration. That is to say that the first face and the second face, previously defined, of the magnetic target, do not have any discontinuity on their respective edges or surfaces. According to an advantageous, but not exclusive, embodiment, the invention provides that the distance, measured radially between the axis of revolution of the magnetic target and the outer face of the latter, is constant over the entire perimeter of this face. exterior. The outer face therefore has, in section along a plane perpendicular to the axis of revolution of the magnetic target, a substantially circular shape. According to this embodiment, the inner face of the magnetic target then has, in section along a plane perpendicular to the axis of revolution of the magnetic target, a non-circular shape, that is to say that the distance, measured radially, between this inner face and the axis of revolution of the magnetic target is not constant: for example, this wall advantageously has a wavy shape around the axis of revolution previously defined.

- the variation of the dimension of the magnetic target measured between the first face and the second face changes direction at the magnetic poles of this. More precisely, at each angular position corresponding to a magnetic extremum region of the magnetic target, that is to say to a region in which the magnetic field North or South of the target is maximum, the variation of the dimension of this magnetic target measured between the first face and the second face changes direction. In other words, this dimension reaches an extremum for each angular position of the magnetic target in which the magnetic field of the latter, North or South, also reaches an extremum. As previously mentioned, the above angular positions are measured around the axis of revolution of the magnetic target, in a plane perpendicular to it, the angular regions designating, by extension, the sectors of the magnetic target corresponding to above-mentioned angular positions.

- The dimension of the magnetic target measured between the first face and the second face is maximum in the regions of the North magnetic pole thereof. In other words, and with reference to the above, the dimension of the magnetic target measured between the first face and the second face is maximum for the angular regions of the latter in which the North magnetic field is maximum.

- The dimension of the magnetic target measured between the first face and the second face is minimum in the regions of the South magnetic pole thereof. In other words, and with reference to the above, the dimension of the magnetic target measured between the first face and the second face is minimum for the angular regions of the latter in which the South magnetic field is maximum.

the dimension of the magnetic target measured between the first face and the second face varies according to a substantially sinusoidal law. More precisely, with reference to an average dimension around which the dimension of the magnetic target measured between the first face and the second face varies, the variations of this dimension of the magnetic target obey a substantially sinusoidal law. This allows, in particular, to act on the harmonics of the signal detected by the position sensor (s) and to improve the precision of the detection. Such a law of variation further limits the signal saturation phenomenon leading to clipping of the latter, and therefore further improves the accuracy of the angular position detection carried out.

- the average distance between the magnetic target and the position sensor (s) is between 1 and 5 millimeters. Preferably, but not exclusively, this average distance is of the order of approximately 3 millimeters. The average distance is here measured perpendicular to the surface of the magnetic target opposite the position sensor (s) considered. More precisely, in the internal or external radial relative configuration, described above, of the magnetic target and of the position sensor (s), the above-mentioned average distance is the distance, measured radially with respect to the axis of revolution of the magnetic target, in a plane perpendicular to this axis of revolution, between the position sensor (s) and a line representing the mean radial dimension, previously defined, of the magnetic target. More precisely still, this mean distance is measured with respect to a center, or crystal, of the sensor considered. For the axial configuration, previously described, of the position sensor (s) relative to the magnetic target, the measurement of the average distance is carried out in a direction parallel to the direction of the axis of revolution of the magnetic target, between a crystal, or center, of the sensor in question, and the surface of the magnetic target located opposite this sensor.

- The detection device according to the invention comprises several position sensors. Preferably, but not exclusively, the detection device according to the invention comprises three position sensors, arranged at approximately ίο to 30 degrees from each other. The angular arrangement of the position sensors is here measured around the axis of revolution of the magnetic target, in a plane perpendicular thereto.

By implementing the aforementioned characteristics, taken separately or in combination, the invention achieves the goals it had set itself, namely, on the one hand, the production of a device allowing precise and reliable detection the angular position of a large diameter rotor, on the other hand, the production of such a simple, reproducible and inexpensive manufacturing detection device and, finally, the production of such a detection device which is integration into a motor vehicle.

The invention also extends to a rotary electric machine intended to, at least, set in motion a motor vehicle, comprising at least:

- a rotor arranged mobile in rotation within a stator,

- At least one device for detecting the angular position of the rotor as described above.

Advantageously, the rotary electric machine according to the invention can both function as an electric generator and as an engine capable of setting the motor vehicle in motion.

Advantageously, the rotary electric machine according to the invention may have one or more of the following characteristics, taken separately or in combination:

at least one position sensor, and advantageously all the position sensors, is integral with the stator of the rotary electric machine,

- the magnetic target movable in rotation around an axis of revolution is integral with the rotor, being centered on the axis of rotation of the rotor,

- The magnetic target of the device for detecting the angular position of the rotor has as many alternations of magnetic poles North, South as there are in the rotor of the rotary electric machine according to the invention.

- an outside diameter of the rotor is greater than 270 millimeters.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below for information, in relation to the following drawings, in which:

FIG. 1 is a schematic perspective view of an exemplary embodiment of a detection device according to the invention,

FIG. 2 is a schematic view from above of a detection device such as that represented by FIG. 1, in the environment of a rotary electric machine,

FIG. 3 is a close-up view of the top view illustrated in FIG. 2,

- And Figure 4 is a schematic perspective view of a rotary electric machine comprising a detection device according to the invention.

It should first of all be noted that if the figures show the invention in detail for its implementation, said figures can of course be used to better define the invention if necessary. It should also be noted that the same elements are designated by the same references on all of the figures.

With reference to the various figures, a detection device 500 comprises a magnetic target 1 and at least one position sensor 2a, 2b, 2c.

According to the non-exclusive embodiment, more particularly illustrated by the figures, such a detection device 500 comprises three position sensors, respectively 2a, 2b, 2c.

With reference to FIG. 1, the magnetic target 1 has the general shape of a straight cylinder portion, with an axis of revolution 100. More specifically, the magnetic target 1 has a first face 10, in this case a inner face 10a, located closest to the axis of revolution 100, and a second face 11, here an outer face 11a, the furthest from the axis of revolution 100. The inner face 10a and the outer face 11a are each radially centered on the axis of revolution 100 of the magnetic target i. In other words, in section along a plane perpendicular to its axis of revolution 100, the magnetic target i has a substantially annular shape centered on the axis of revolution 100. This is more particularly visible in FIG. 2. From a electromagnetically, the magnetic target i has, around its axis of revolution loo previously defined, a succession of alternations of north and south magnetic poles.

The magnetic target i is, for example, produced by injecting, into a mold, a polymer resin, for example a resin based on polyamide or polyphenyl, or an elastomeric material charged with magnetic particles, for example particles of ferrite or rare earth particles. More generally, the materials used to manufacture the magnetic target are advantageously chosen to meet the constraints of rigidity and resistance at high temperature imposed by the environment and by the operation of a rotary electric machine equipped with the detection device 500 according to the invention.

According to the invention, the dimension 15 of the magnetic target 1, measured between the first face 10 and the second face 11, previously defined, of the magnetic target 1, is not constant around the periphery of the magnetic target 1. L thickness of the magnetic target 1 varies, evolving circularly around the axis of revolution 100 of the magnetic target 1. According to the example illustrated in FIG. 3, this dimension 15 is measured radially with respect to the axis of revolution 100.

According to the embodiment illustrated by FIGS. 1 to 3, a distance 12, measured radially between the axis of revolution 100 of the magnetic target 1 and the outer face 11a of the latter, is constant, that is to say saying that the outer face 11a previously defined has, in section along a plane perpendicular to the above-mentioned axis of revolution 100, a substantially circular shape, to within the manufacturing tolerances, this circular shape being centered on the axis of revolution 100. According to this exemplary embodiment, a distance 13, measured radially between the axis of revolution 100 of the magnetic target 1 and the interior face 10a previously defined, is not constant. More specifically, in section along a plane perpendicular to the aforementioned axis of revolution 100, the inner face 10a has a wavy shape around the axis of revolution 100. This shape is, of course, not exclusive, and any other shape generating a variation in the thickness of the target can be considered in the context of the invention.

As shown in Figures i to 3, the radial dimension 15, previously defined, has a continuous succession of alternations of maxima 15a and minima 15b, the inner face 10a of the magnetic target 1 having no discontinuity.

According to the invention and as visible in FIG. 3, the maxima 15a and the minima 15b are located in regions of the magnetic target 1 in which the magnetic field has an extremum. More precisely, the maxima 15a and the minima 15b of the radial dimension 15 are located in angular positions, respectively 150a and 150b, in which the magnetic field of the magnetic target 1 is maximum. In other words, whatever the nature of the extremum reached by the radial dimension 15 at an angular position of maximum North or South polarization, the variation of the radial dimension 15 of the magnetic target 1 changes direction with each change. of magnetic pole around the axis of revolution 100 previously defined.

It should be understood here that the aforementioned angular positions are measured around the axis of revolution 100 of the magnetic target 1, in a plane perpendicular to the aforementioned axis of revolution 100, and with respect to an origin defined as the axis of revolution 100. According to a particularly advantageous embodiment of the invention, the maxima 15a of the radial dimension 15 are located at angular positions 150a of the magnetic target 1 in which the magnetic field of North polarization is maximum, and the minima 15b of the radial dimension 15 are located at angular positions 150b of the magnetic target 1 in which the magnetic field of South polarization is maximum.

Thus, according to such an embodiment, between an angular region of polarization South and an angular region of polarization North of the magnetic target 1, around the axis of revolution 100 previously defined, the radial dimension 15 increases until reaching a maximum 15a at the angular position 150a of maximum north polarization, then the radial dimension 15 decreases, around the aforementioned axis of revolution 100, to the next angular region of south polarization where this radial dimension 15 reaches a minimum 15b at the angular position of maximum South polarization.

According to a particularly advantageous embodiment of the invention, the variation of the radial dimension 15, previously defined, between maximum 15a and minimum 15b, follows a sinusoidal, or substantially sinusoidal, law.

As mentioned above, the detection device 500 according to the invention comprises, according to the embodiment more particularly illustrated by the figures, three position sensors, respectively referenced 2a, 2b, 2c. For example, the position sensors 2a, 2b, 2c are sensors of the Hall effect type, that is to say that they are configured to measure variations in the magnetic field. Advantageously, the position sensors 2a, 2b, 2c, are arranged at angular positions of approximately 10 to 30 degrees from each other, measured around the axis of revolution 100 of the magnetic target 1, in a plane perpendicular to this one.

More particularly visible in FIGS. 1 and 2, the position sensors 2a, 2b, 2c, are arranged radially between the axis of revolution 100 and the interior face 10a, previously defined, of the magnetic target 1. This relative configuration is called internal radial configuration. Alternatively, the position sensors 2a, 2b, 2c can be, for example, arranged in an external radial configuration in which they are placed radially with respect to the axis of revolution 100 of the magnetic target 1 so that the external face 11a of the latter is located radially, with respect to the axis of revolution 100, between the latter and the position sensors 2a, 2b, 2c. According to another alternative embodiment, the position sensors 2a, 2b, 2c, can be arranged axially with respect to the magnetic target 1, that is to say with regard to a surface thereof perpendicular to the axis revolution 100 mentioned above.

With particular reference to FIGS. 1 and 4, the magnetic target 1 is received in a target holder 3 of which an axis of revolution 300 is substantially coincident, apart from manufacturing and wear tolerances, with the axis of revolution 100 of the magnetic target i.

More specifically, the target holder 3 has, in section along a plane containing its axis of revolution 300, the general shape of a U whose axis of symmetry is constituted by the aforementioned axis of revolution 300. The target holder 3 thus forms a substantially cylindrical receiving housing 30, the axis of revolution of which coincides with the axis of revolution 300 of the target holder 3. The target holder 3 is thus delimited by a wall 35 and a bottom 34 , the wall comprising an inner surface 31, an outer surface 33 and a bottom 34, the assembly forming an open ring on the top. The bottom 34 is provided with a through hole for certain components of the rotor, such as its axis for example.

In the internal radial relative configuration of the magnetic target 1 and of the position sensors 2a, 2b, 2c, more particularly illustrated by FIGS. 1 to 3, the outer face 11a of the magnetic target 1 is received against the inner surface 31 of the wall 35 above. The magnetic target 1 is thus located inside the volume 32 defined by the receiving housing 30 and delimited in particular by the above-mentioned interior surface 31. In this internal radial configuration, the external face 11a of the magnetic target 1, parallel to the axis of revolution 100 of the latter, is therefore received against the internal surface 31 of the wall 35 of the target holder 3, parallel to the axis of revolution 300 of the latter, coincident with the axis of revolution 100 of the magnetic target. In this internal radial configuration, the position sensors 2a, 2b, 2c are placed radially, in the reception housing 30 previously defined, between the axis of revolution 100, 300, common to the magnetic target 1 and to the target holder 3, and the inner face 10a of the magnetic target 1.

In the external radial relative configuration of the magnetic target 1 and of the position sensors 2a, 2b, 2c, previously described and not shown in the figures, the internal face 10a of the magnetic target 1 is received against the external surface 33 of the wall 35 cited above. The magnetic target 1 is thus located outside the volume 32 previously described. In this external radial configuration, the position sensors 2a, 2b, 2c are placed radially outside the reception housing 30 previously defined, and the magnetic target 1 is therefore located between the axis of revolution 100 and the sensors of position 2a, 2b, 2c.

Advantageously, in an external radial configuration as just described, the internal face 10a of the magnetic target i has, in section along a plane perpendicular to the axis of revolution 100, 300, common to the magnetic target 1 and to the target holder 3, a substantially circular shape, that is to say that the distance 13, previously defined, between and the inner face 10a of the magnetic target 1 and the axis of revolution 100, 300, common to the latter and target 3, is constant. It follows that, in such an external radial configuration, the distance 12, previously defined, between the external face 11a of the magnetic target 1 and the axis of revolution 100, 300, common to the latter and to the target holder 3, n is not constant. For example, the outer face 11a of the magnetic target has, in section along a plane perpendicular to the common axis 100, 300, mentioned above, a wavy shape around this axis.

In the relative axial configuration of the magnetic target 1 and of the position sensors 2a, 2b, 2c, previously described and not shown in the figures, the reception housing 30 previously defined comprises, perpendicular to its axis of revolution 300, the bottom 34 constituted by the horizontal branch of the U-shape that the target holder 3 has in section along a plane containing its axis of revolution 300. In this relative axial configuration of the magnetic target 1 and the position sensors 2a, 2b, 2c, the magnetic target 1 advantageously has the shape of a ring whose dimension, along the above-mentioned axis of revolution 100, is small, and the position sensors 2a, 2b, 2c, are arranged, in a direction parallel to the axis of revolution 100, 300, common to the magnetic target 1 and to the target holder 3, with regard to an annular surface of this ring, this annular surface being perpendicular to the common axis of revolution 100, 300, supra. This axial configuration is in particular recognizable by a regular undulation of this annular surface, the latter being directly facing the position sensors.

According to different embodiments, the magnetic target 1 can be injection molded or attached by bonding to one of the faces of the target holder 3.

Whatever their relative configuration, that is to say internal radial, external radial or axial configuration relative to the magnetic target i, the invention provides that, in the detection device 500, the position sensors 2a, 2b , 2c are fixed relative to the magnetic target 1, itself driven in rotation about its axis of revolution 100.

It therefore follows from the above that, in the rotational movement of the magnetic target 1 around its axis of revolution 100, the angular regions of the magnetic target 1, of variable radial dimension, scroll successively with regard to the position sensors 2a, 2b, 2c. In other words, in the rotational movement of the magnetic target 1 around its axis of revolution 100, a distance 16 visible in FIG. 3, measured radially with respect to the aforementioned axis of revolution 100, between the magnetic target and the position sensors 2a, 2b, 2c, varies. Advantageously, the above-mentioned distance 16 has an average value of the order of 1 to 5 millimeters, preferably approximately 3 millimeters. This mean value of the distance 16 is here defined as the distance, measured radially with respect to the axis of revolution 100 of the magnetic target 1, in a plane perpendicular to this axis of revolution 100, between the position sensor (s) 2a , 2b, 2c and a line representing an average radial dimension 15c of the magnetic target 1, the average radial dimension 15c, being defined as the value of the radial dimension 15, previously defined, around which this quantity varies along the periphery of the magnetic target 1.

The combination of the variations of the radial dimension 15 previously defined with the variations of the magnetic field of the target 1 then causes a modification of the magnetic signal received by the position sensors 2a, 2b, 2c. According to the invention, the variations in the aforementioned radial dimension are defined so that this magnetic signal meets the requirements sought in terms of harmonics, variation of the voltage amplitude and clipping of this signal. For example, the variation, previously mentioned, of the radial dimension 15 of the magnetic target 1 according to a substantially sinusoidal law, makes it possible to act on the harmonics of the signal detected by the position sensors 2a, 2b, 2c, and to improve the precision of the detection of the desired angular position. Such a law of variation further limits the signal saturation phenomenon leading to clipping of the latter, and therefore further improves the accuracy of the angular position detection carried out.

FIG. 4 schematically illustrates a rotary electric machine 600 according to the invention, intended in particular for setting in motion a motor vehicle, and equipped with a detection device 500 as just described.

With reference to FIG. 4, the rotary electric machine 600 comprises the rotor 4, which can move in rotation about the axis of rotation 400. In the rotary electric machine 600, the rotor 4 is placed inside the stator 5 relative to to which it is movable in rotation about the aforementioned axis of rotation 400. Advantageously, the stator 5 has a general shape of revolution, the axis 500 of which is substantially coincident, with the tolerances of manufacture, assembly and wear, with the axis of rotation 400 of the rotor 4. Advantageously, the stator 5 is consisting of a set of electromagnetic coils schematically shown in Figures 3 and 4. The stator 5 is received in a housing 6 to which it is connected by suitable fixing means, not detailed in the figures.

From an electromagnetic point of view, the rotor 4 has, angularly relative to its axis of rotation 400, a succession of alternations of North and South magnetic poles.

To detect the angular position of the rotor 4 within the rotating electrical machine 600, the magnetic target 1 is linked in rotation to the rotor 4, and its magnetic configuration is representative of that of the rotor 4. More precisely, within the rotary electrical machine 600 according to the invention, the magnetic target 1 is arranged in such a way that its axis of revolution 100, previously defined, is substantially coincident, with the manufacturing, assembly and wear tolerances, with the axis rotation 400 of the rotor 4, previously defined. According to different embodiments of the invention, the magnetic target 1 has the same number of alternations of North and South magnetic poles as the rotor 4, or it has a number of alternations of North, South magnetic poles, less than the number alternation of these magnetic poles that presents the rotor 4 Furthermore, as mentioned above, to carry out the detection of the angular position of the rotor 4 within the rotary electrical machine 600, the position sensors, here in number of three, 2a, 2b, 2c, must be fixed relative to the magnetic target 1 driven in rotation by the rotation of the rotor 4 around the axis 100, 400 common to these two elements. To do this, in the rotary electric machine 600 according to the invention, the position sensors 2a, 2b, 2c are made integral with the stator 5, itself fixed relative to the rotor 4 to which the magnetic target 1 is linked.

According to the exemplary embodiment, more particularly illustrated by FIGS. 2 to 4, the position sensors, three in number, 2a, 2b, 2c, are placed on a support 51, approximately approximately 15 degrees from each other relatively to the common axis 100, 400, of the magnetic target 1 and of the rotor 4. More specifically, the support 51 is, according to this particular embodiment, in the form of a portion of disc centered on the common axis 100, 400, previously described and extending over an angular sector of between 20 ° and 6o ° configured to accommodate all the position sensors 2a, 2b, 2c.

By implementing the means which have just been described, the invention makes it possible to detect the angular position of a rotor 4 of a rotary electrical machine 600 with great precision and while minimizing possible deformations or disturbances of the signal received by the position sensors 2a, 2b, 2c previously described. By implementing these means, the invention finds a particularly advantageous, but not exclusive, application for the detection of the angular position of rotors 4 of large diameter. This is the case, in particular, for rotary electrical machines 600 in which the diameter of the rotor 4 is greater than 270 millimeters.

The invention therefore achieves the goals it set for itself.

The invention as it has just been described cannot however be limited to the means and configurations exclusively described and illustrated, and also applies to all means or configurations, equivalent and to any combination of such means or configurations. In particular, the invention applies, as described above, to any relative configuration of the magnetic target 1 and of the position sensors 2a, 2b, 2c of internal radial, external radial or axial configuration, as well as any number, type or configuration of position sensors 2a, 2b, 2c, insofar as these are fixed relative to the magnetic target 1 driven in rotation by the rotation of a rotor 4 of a rotating electric machine 600.

Claims (11)

1. Device (500) for detecting the angular position of a rotor (4) of a rotary electric machine (600) intended to set in motion a motor vehicle, the rotor (4) being mounted so as to be able to rotate in a stator (5) of the rotary electric machine (600), the device (500) for detecting the angular position of the rotor (4) comprising at least: - at least one position sensor (2a, 2b, 2c) configured to be integral with the stator (5) of the rotary electric machine (600), - a magnetic target (1) comprising North and South magnetic poles, the magnetic target (1) comprising a first face (10, 10a) and a second face (11, 11a), the magnetic target (1) being movable in rotation about an axis of revolution (100), configured to be centered on an axis of rotation (400) of the rotor (4), characterized in that a dimension (15) measured between the first face (10, 10a) and the second face (11,11a) is variable. 2. Device (500) according to claim 1, characterized in that a variation in the dimension (15) of the magnetic target (1) measured between the first face (10,10a) and the second face (11,11a) is regular. 3. Device (500) according to claim 1 or 2, characterized in that a variation in the dimension (15) measured between the first face (10, 10a) and the second face (11, 11a) changes direction at the poles of the magnetic target (1). 4. Device (500) according to any one of the preceding claims, characterized in that the dimension (15) of the magnetic target (1) measured between the first face (10,10a) and the second face (11,11a) is maximum in the North magnetic pole regions thereof. 5. Device (500) according to any one of the preceding claims, characterized in that the dimension (15) of the magnetic target (1) measured between the first face (10, 10a) and the second face (11, 11a) is minimal in the South magnetic pole regions thereof. 6. Device (500) according to any one of the preceding claims, characterized in that the dimension (15) of the magnetic target (1) measured between the first face (10, 10a) and the second face (11, 11a) varies according to a substantially sinusoidal law. 7. Device (500) according to any one of the preceding claims, characterized in that the magnetic target (1) is a ring of a plastic material charged with magnetic particles. 8. Device (500) according to any one of the preceding claims, characterized in that an average distance (16) between the magnetic target (1) and the at least one position sensor (2a, 2b, 2c) is between 1 and 5 mm. 9. Device (500) according to any one of the preceding claims, characterized in that it comprises three position sensors (2a, 2b, 2c) arranged angularly between ten and fifteen degrees from each other. 10. Rotating electric machine (600) intended to at least set in motion a motor vehicle, comprising at least: - a stator (5), - a rotor (4) disposed inside the stator (5) and mounted so as to be able to rotate relative to the latter, - At least one device (500) for detecting the angular position of the rotor (4) according to any one of the preceding claims. 11. Rotating electric machine (600) according to the preceding claim, characterized in that the stator (5) has an outside diameter greater than 270 millimeters.