FR3065848B1 - MOTORIZED DEVICE FOR MOTOR VEHICLE AND ASSOCIATED DRIVING ASSISTANCE SYSTEM - Google Patents

Abstract

The invention relates to a motorized device (3) for a motor vehicle comprising an accessory (4) for a motor vehicle (100) mounted movably in rotation about an axis of rotation (A1) and a motor (5) configured to drive in rotation the accessory (4), said motor (5) comprising a rotor (51) and a stator (53), the motorized device (3) comprising: - a fixed part (33) comprising the stator (53), - a part mobile (31) comprising the rotor (51) and the accessory (4) integral in rotation with the rotor (51). According to the invention, at least one magnetic bearing (28) is arranged between the fixed part (33) and the movable part (31) of the motorized device (3). Said at least one magnetic bearing (28) comprises at least one first magnetic ring mounted integral with the movable part (31) and at least one second magnetic ring mounted integral with the fixed part (33). The invention also relates to a corresponding driver assistance system (1).

Description

Motorized device for a motor vehicle and associated driving assistance system

The present invention relates to the field of motorized devices for vehicles including automobiles. In particular, the invention applies to the field of driving assistance and especially to driver assistance systems, installed on certain vehicles, the driving assistance system possibly comprising an optical sensor, such as example a camera comprising a lens.

Motorized devices can be used to rotate various motor vehicle equipment or accessories. The problem of congestion being constant in the automotive field, the motorized devices include smaller and smaller engines while maintaining sufficient power and rotational speeds for the proper operation of the equipment or accessory. The present invention relates in particular to a motorized device comprising a small electric motor, or even a miniature electric motor.

In the context of the present invention, a small electric motor is understood to mean a stepping motor, an actuator, a DC motor with or without a brush, an asynchronous motor or a synchronous motor whose mass is less than 10 kg. , or even less than 1 kg, in particular used to operate equipment for vehicles.

By miniature electric motor is meant in the context of the present invention a stepper motor, an actuator, a DC motor with or without brushes, an asynchronous motor or a synchronous motor, whose mass is less than 200g or less at 100 g, preferably between 30 g and 100 g, for example between 30 g and 60 g.

This may include a hollow motor.

For example, in the field of driving assistance, front, rear or side vision cameras are used in a large number of motor vehicles. In order to maintain a wide angle of view for such cameras, they are generally installed outside motor vehicles at different locations depending on the desired use. In this case, the camera is highly exposed to the projections of mineral or organic dirt that can be deposited on its optics and thus reduce its effectiveness or render it inoperative. One solution provides for arranging the camera in a housing closed by a rotary cover driven by a motorized device.

In known motorized devices, mechanical bearings such as ball bearings are used to guide the rotation of the equipment or mobile accessory integral in rotation of the rotor with respect to the fixed stator or a fixed support of the motorized device. A major disadvantage of such mechanical bearings is the friction generated and the need for lubrication. However some lubricating oils used can degas strongly or even produce toxic fumes, which generates pollution.

The present invention proposes to remedy at least partially the disadvantages mentioned above by proposing a motorized device for a motor vehicle to reduce the size of the engine while limiting the problems of friction and pollution. For this purpose the invention relates to a motorized device for a motor vehicle comprising an accessory for a motor vehicle mounted to rotate about an axis of rotation and a motor configured to rotate the accessory, said motor comprising a rotor and a stator, the motorized device comprising: a fixed part comprising the stator, and a movable part comprising the rotor and the accessory integral in rotation with the rotor,

According to the invention, the motorized device further comprises at least one magnetic bearing arranged between the fixed part and the mobile part of the motorized device. Said at least one magnetic bearing comprises at least a first magnetic ring mounted integral with the movable part and at least a second magnetic ring mounted integral with the fixed part.

Such a magnetic bearing is non-contact and makes it possible to replace the mechanical bearing or bearings, such as ball bearings, used in the motorized devices so as to make the movable part of the motorized device levitated permanently with respect to the fixed part, without no friction contact. This solution makes it possible to eliminate all the friction and viscosity of the bearings of the solutions of the prior art. In addition, this eliminates the need for lubrication bearings and the risk of internal degassing.

Said device may further comprise one or more of the following characteristics, taken separately or in combination: said device comprises between one and four magnetic bearings; said device further comprises at least one mechanical bearing; said at least one mechanical bearing is a ball bearing; said at least one magnetic bearing is arranged between the stator and the rotor of said motor; said at least one magnetic bearing comprises a predefined number of first and second magnetic rings, each first and second magnetic ring having two concentric faces of opposite poles; said at least one first magnetic ring is mounted integral with the rotor; said at least one second magnetic ring is mounted integral with the stator; said at least one first magnetic ring is spaced from said at least one second magnetic ring by an air gap; said at least one magnetic bearing has an even number of first magnetic rings and second magnetic rings; said at least one magnetic bearing preferably comprises two first magnetic rings and two second magnetic rings; first two magnetic rings, respectively two second magnetic rings, are spaced apart by an air gap; said at least one magnetic bearing comprises two concentric support rings; said at least one magnetic bearing has at least one conical portion; said at least one magnetic bearing has at least one face extending in a direction oblique to the axis of rotation of the motor; the motorized device comprises at least two magnetic bearings each having at least one face extending in a direction oblique to the axis of rotation of the motor; said at least one face extending in a direction oblique with respect to the axis of rotation of the motor is a face of generally conical or frustoconical shape; the two magnetic bearings are arranged opposite to a median plane of the motor perpendicular to the axis of rotation of the motor; the engine is a hollow motor; the motor is a brushless motor; the accessory is for example part of a driver assistance system; the accessory is a means of protecting an optical sensor of a driver assistance system; the accessory is at least partially transparent; the accessory comprises in particular an optical element configured to be disposed upstream of an optics of the optical sensor. The invention also relates to a driving assistance system comprising an optical sensor and a motorized device as defined above. According to one aspect of the invention, the accessory is a means of protection of the optical sensor. Other features and advantages of the invention will emerge more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings in which: FIG. 1 schematically represents a motor vehicle comprising a driver assistance system comprising a motorized device according to the invention, - Figure 2a is a partial longitudinal sectional view of the motorized device of Figure 1, - Figure 2b is a front view and in perspective of the device FIG. 3 is a sectional view schematically showing a portion of an embodiment of a motorized device according to the invention; FIG. 4 illustrates a motorized device variant according to the invention; FIG. 5 illustrates another variant of a motorized device according to the invention; FIG. 6 illustrates yet another variant of a motorized device. according to the invention, - Figure 7 is a perspective view of a magnetic bearing of a motorized device of Figures 2a to 6, - Figure 8 is a cross-sectional view of the magnetic bearing of Figure 7, - the FIG. 9a is a schematic front view of a group of a first magnetic ring and a second magnetic ring of the magnetic bearing of FIGS. 7 and 8, and FIG. 9b is a schematic view of another group of FIGS. a first magnetic ring and a second magnetic ring whose poles are inverted with respect to FIG. 9a; FIG. 10 is a cross-sectional view of a magnetic bearing of the example of FIG. 4; and FIG. 11 is a cross-sectional view of an additional bearing of the example of FIG. 6.

In these figures, the identical elements bear the same references.

The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Simple features of different embodiments may also be combined or interchanged to provide other embodiments.

In the description, it is possible to index certain elements, such as for example first element or second element. In this case, it is a simple indexing to differentiate and name close but not identical elements. This indexing does not imply a priority of one element with respect to another and it is easy to interchange such denominations without departing from the scope of the present description. This indexing does not imply an order in time either. The invention is in the field of motor vehicles 100. In particular, the invention can be applied to a motor vehicle 100 equipped with a system 1 for driving assistance. Such a vehicle is shown diagrammatically in FIG. 1. The invention relates to a motorized device 3 for a motor vehicle 100. In particular, such a motorized device 3 can be part of the driver assistance system 1 fitted to the motor vehicle 100.

In known manner, the driving assistance system 1 comprises in particular at least one optical sensor 13. The optical sensor 13 is for example an optical sensor 13 for shooting such as a camera. It may be a CCD ("coupled coupled device") or a CMOS sensor comprising a matrix of miniature photodiodes. According to another variant, it may be a sensor for remote sensing laser called LIDAR sensor, acronym in English of "light detection and ranging".

As can be seen more clearly in FIGS. 2a and 2b, the optical sensor 13 has an optic 14 optical 15. The optic 14 is for example a lens. This optic 14 is for example convex (convex) of convexity oriented towards the outside of the optical sensor 13, such as a so-called fish-eye optics ("fish-eye" in English).

According to the example illustrated in Figure 1, the motorized device 3 is mounted at the front of the motor vehicle 100, at a bumper. Of course, alternatively the motorized device 3 can be mounted at the rear of the motor vehicle 100, for example at the bumper or the license plate. It can also for example be mounted on the sides of the vehicle, for example at the mirrors.

The motorized device 3 may be fixed according to any known technique, on any element 2 of the motor vehicle 100, such as a bodywork element or an external element such as a bumper, a rearview mirror or a license plate.

More specifically, with reference to FIG. 2a, the motorized device 3 comprises: at least one accessory 4 for a motor vehicle 100 rotatably mounted about an axis of rotation A1, and a motor 5 configured to drive in rotation 4. The accessory 4 is for example a part of the driver assistance system 1. Without limitation, the accessory 4 may be a means of protection of the optical sensor 13 of the system 1 to assist the conduct. The accessory 4 may be at least partially transparent. In particular when the motorized device 3 is part of a driving assistance system 1, and the accessory 4 is a means of protection of the optical sensor 13, the accessory 4 is advantageously partially or entirely transparent.

According to the embodiment described, the accessory 4 comprises a housing 6, better visible in Figures 2a and 2b.

According to this embodiment, the accessory 4 also advantageously comprises an optical element 9.

As regards the housing 6, it is rotatably mounted about the axis of rotation Al.

The housing 6 may be centered around rotational axis A1 of the housing 6. In this example, the housing 6 is generally substantially cylindrical in shape.

The housing 6 may be made of any suitable material known to those skilled in the art, for example aluminum or a thermally conductive polycarbonate.

Moreover, the optical sensor 13 is in this example mounted in the housing 6. To do this, the housing 6 comprises a housing 19 (see Figure 2a) configured to receive the optical sensor 13, for example so that the optical 15 of the optical sensor 13, or coincides with rotation axis Al of the housing 6.

The housing 19 can also receive the motor 5, for example here at the rear of the housing 6.

Preferably, the housing 6 is a sealed housing. The optical element 9, meanwhile, is intended to protect the optics 14 of the optical sensor 13 possible projections of dirt or solid debris that could damage this optic 14. This is therefore a protective element, or more precisely of a protective mask of the optical sensor 13, and it is this optical element 9 which is subjected to attacks from the outside, that is to say both water splashes, pollutants, gravel only pollutant deposits or traces of water. The optical element 9 is arranged at the front of the motorized device 3 so as to face a road scene whose optical sensor 13 is configured to take part in the shooting.

The motor 5 is for example arranged on the opposite side to the optical element 9. The optical element 9 is for example transparent. This optical element 9 may be made of glass or a transparent plastic material such as polycarbonate. The optical element 9 can be made in one piece with the housing 6. Alternatively, the housing 6 and the optical element 9 can be made by two separate parts secured. By way of non-limiting example, the connection between the housing 6 and the optical element 9 can be done by ultrasonic welding. The housing 6 being integral with the optical element 9, this forms a sealed block thus preventing the introduction of dirt inside the housing 6 intended to receive the optical sensor 13 and the motor 5. The optical element 9 is arranged at the front of the accessory 4, in this example at the front of the housing 6. The front of the housing 6 or the accessory 4 is the part intended to cope with the road scene whose optical sensor 13 participates in the shooting, when the accessory 4 is mounted on the motor vehicle 100 (Figure 1). In contrast, the rear of the housing 6 (Figures 2a, 2b) is the portion of the housing 6 opposite the front of the housing 6; the rear of the housing 6 is the furthest part of the road scene whose optical sensor 13 participates in the shooting.

In addition, the optical element 9 is also rotatably mounted about the axis of rotation A1. More specifically, the housing 6 can be arranged to be rotated by the motor 5 (FIG. 2a), which allows the rotation of the optical element 9. The optical element 9 is therefore configured to be rotated with the housing 6, so as to allow protection of the optical element 9 by a centrifugal effect. The optical element 9 is advantageously arranged centrally with respect to the axis of rotation A1. This optical element 9 has in particular a symmetry of revolution with respect to the axis of rotation A1.

Pat elsewhere, according to the illustrated embodiment, the optical element 9 is distinct from the optical sensor 13. This optical element 9 is configured to be disposed upstream of the optical sensor 13, more precisely upstream of the optics 14 of the optical sensor 13. In particular, the optical element 9 can be arranged so that the rotation axis A1 of the optical element 9 coincides with the optical axis 15 of the optical sensor 13. In the present, the upstream term is defined relative to the optical axis 15 and with respect to the road scene whose optical sensor 13 participates in the shooting. In other words, it is understood by "upstream" of the optic 14, a position in which the optical element 9 is disposed between the optics 14 and the road scene whose optical sensor 13 participates in the shooting, according to the optical axis 15. The optical element 9 being disposed upstream of the optics 14 of the optical sensor 13, its production in a transparent material makes it possible not to harm the efficiency of the optical sensor 13.

In addition, the optical element 9 is dimensioned so as to cover the entire surface of the optic 14. At the assembly of the motorized device 3 and the optical sensor 13 on the motor vehicle 100 (also referring to FIG. ), the optical element 9 is arranged centrally with respect to the optical sensor 13, more precisely centrally with respect to the optic 14.

Advantageously, referring again to FIGS. 2a and 2b, the optical element 9 has a general shape substantially similar to the shape of the optic 14. In this example, the optical element 9 is at least partly of substantially convex, with a curve substantially parallel to the curved surface of the optic 14 of the optical sensor 13.

According to an alternative not shown, the optical element 9 may be formed by an external lens of the optical sensor 13.

In addition, in order to avoid a phenomenon of condensation between the optic 14 and the optical element 9, the inner surface of the optical element 9 advantageously has an anti-fogging property. The inner surface of the optical element 9 is the surface intended to be arranged facing the optic 14 of the optical sensor 13. In particular the inner surface of the optical element 9 has an anti-fog coating.

Alternatively or in addition, the outer surface of the optical element 9 may have one or more of the following properties: hydrophobic, infra-red, photocatalytic, super hydrophobic, oleophobic, lipophobic, hydrophilic, or even superhydrophilic, resistance to gravel , or any other surface treatment to reduce the adhesion of dirt. In particular, thanks to the hydrophobic properties of the outer surface of the optical element 9, any drops of water will run on the outer surface without leaving any traces because the water will not adhere to this external surface.

Referring more particularly to Figure 2a, which relates to the engine 5, it is particularly a miniature engine. By miniature engine means a small engine especially suited for automotive equipment.

In particular, it is a hollow motor. By way of non-limiting example, it may be more particularly a brushless motor, also known under the name "brushless motor" in English.

The motor 5 can have a rotation speed of between 1000 and 50000 revolutions / minute, preferably between 5000 and 20000 revolutions / minute, and more preferably between 7000 and 15000 revolutions / minute. The motor 5 is for example electrically powered by a power supply connected to the general electrical circuit of the motor vehicle 100 (also referring to Figure 1).

The motor 5 is configured to rotate the accessory 4, namely in this example the housing 6 and the optical element 9 integral with the housing 6.

The motor 5 is rotatably mounted about an axis of rotation A2. In the example illustrated in FIG. 2a, the motor 5 is arranged so that its axis of rotation A2 coincides with the axis of rotation A1 of the optical element 9, and with the optical axis 15 of the optical sensor 13. .

The motor 5 comprises a rotor 51 and a stator 53. The stator 53 is fixed and the rotor 51 is rotatable relative to the fixed stator 53.

According to the embodiment described, the housing 6 and the optical element 9 are integral in rotation with the rotor 51 of the motor 5.

According to the illustrated embodiment, the rotor 51 is disposed around the stator 53. The stator 53 is therefore inside and the rotor 51 outside. Of course, this arrangement is not limiting and it is possible to envisage a reverse arrangement in which the rotor 51 is rotatably mounted inside the stator 53 outside.

In addition, the motor 5 is in this example arranged in the extension of the optical sensor 13. The motor 5 being hollow, it can receive at least partly the optical sensor 13. In particular, according to the configuration illustrated, it is the stator 53 of the motor 5 which is hollow and can receive a portion of the optical sensor 13. This is a rear portion of the optical sensor 13 on the side opposite to the optic 14, more precisely it is a question of a support part 17, in particular a fixed part, of the optical sensor 13.

The motorized device 3 thus comprises: a mobile part 31 comprising the rotor 51, and a fixed part 33 comprising the stator 53.

According to the embodiment described, the movable portion 31 of the motorized device 3 also comprises and at least one movable element integral in rotation with the rotor 51, such as in particular the accessory 4, that is to say the housing 6 and the optical element 9 in this example.

Similarly, the fixed portion 33 may also comprise an element or support fixed to the stator 53. Of course, the element or support may be fixed directly or not to the stator 53. Without limitation, in this example, the fixed part 33 the motorized device 3 comprises a fixed support 46 for mounting the motorized device 3 on the motor vehicle 100, also referring to Figure 1. There is also talk of mounting bracket.

This fixed support 46 is in particular fixed to the stator 53.

Referring more particularly to FIGS. 2a and 2b, the fixed support 46 may comprise a front part which has an opening 45 for the passage of the optical element 9 and the optic 14 of the optical sensor 13, to thus allow vision outwards. This opening 45 is for example arranged so as to be arranged facing a complementary opening of the element 2 of the motor vehicle 100 (also referring to Figure 1), so that once the fixed support 46 installed on the element 2 of the motor vehicle 100, the optical 14 of the optical sensor 13 and the optical element 9 protrude from the opening 45 and the opening in the element 2 of the motor vehicle 100 (see FIGS. at 2b).

The fixed support 46 advantageously also comprises an opening 47 at the rear of the motorized device 3, better visible in FIG. 2a, to enable the optical sensor 13 to be connected to cables (not shown) necessary for the operation of the optical sensor 13. Advantageously, there is provided a sealed arrangement at the rear of the motorized device 3 for the passage of cables or son to limit the entry of water vapor and / or other contaminants in the housing 6. In particular, the opening 47 is sealed to limit entry of water vapor and / or other contaminants into the housing 6.

Referring to Figures 2a and 3 to 11, the motorized device 3 further comprises at least one bearing 27, 28, 270, 280, 29, 27 ', 28'.

According to the example shown in Figure 2a or schematically in Figures 3 to 5, the motorized device 3 comprises two bearings 27 or 270 or 27 ', and 28 or 280 or 28', or more than two bearings 27, 28 29, as shown in FIG. 6. The bearings 27, 270, 27 ', 28, 280, 28', 29 are shown diagrammatically in FIGS. 2a and 3 to 6.

In the example of FIGS. 2a, 3 and 6 to 9b, the bearing or bearings 27 or 27 ', and 28 or 28', or else 29, are generally of substantially annular or cylindrical shape, or else of general disc shape. Alternatively, as illustrated in Figures 4, 5 and 10, the bearing or bearings 270, 280 may have at least one cone portion, as will be described in more detail later.

These bearings 27, 270, 27 ', 28, 280, 28', 29 are each arranged between the mobile part 31 and the fixed part 33 of the motorized device 3.

In addition, the bearings 27, 270, 27 ', 28, 280, 28' or 29 are arranged concentrically with the motor 5.

Referring to the particular example illustrated in FIG. 2a, a bearing, namely the bearing 27 'in the example of FIG. 2a, can be arranged outside the housing 6, between the optical element 9 and a part, especially a front part, of the fixed support 46. This bearing 27 'allows the rotation of the housing 6 relative to the fixed support 46. Another bearing, the bearing 28 in the example of Figure 2a, is arranged between the rotor 51 and the stator 53 of the motor 5. This bearing 28 allows the rotation of the housing 6 secured to the rotor 51 relative to the stator 53 of the motor 5.

Alternatively, as shown diagrammatically in FIG. 3 or FIG. 6, the two bearings 27 and 28 can be arranged between the rotor 51 and the stator 53.

According to the invention, the motorized device 3 comprises at least one magnetic bearing 27 or 270, 28 or 280, or 29 arranged between the fixed part 33 and the mobile part 31 of the motorized device 3.

In particular for such an application, the motorized device 3 may include, without limitation, one and four magnetic bearings 27 or 270, 28 or 280, or 29.

According to the embodiment illustrated in Figure 2a, at least one of the bearings 27 ', 28 previously described is therefore a magnetic bearing. This is for example the bearing 28 arranged between the rotor 51 and the stator 53 of the motor 5, which is a magnetic bearing. Conversely, it is conceivable that it is the bearing 27 'disposed between the optical element 9 and the fixed support 46 which is the magnetic bearing. The other bearing, for example the bearing 27 'according to the embodiment of Figure 2a, can be removed. In this case, the motorized device 3 may comprise a single bearing 28 which is a magnetic bearing.

Alternatively, the other bearing, for example the bearing 27 'in the example of Figure 2a, may be a mechanical bearing such as a ball bearing. In this case, the motorized device 3 may comprise at least one magnetic bearing 28 and at least one mechanical bearing 27 '. Such a mechanical bearing such as a ball bearing is well known and is not described in more detail herein. Such a variant is also schematically simplified in Figure 5 with a magnetic bearing 270 and a ball bearing 28 '. As described below, according to this variant the magnetic bearing 270 has at least one cone portion, for example the magnetic bearing 270 is generally conical or frustoconical. In this way, it has at least one face extending obliquely relative to the axis of rotation A2 of the motor 5. This arrangement makes it possible to constrain the mechanical bearing 28 '.

Alternatively, the two bearings 27 or 270 and 28 or 280 may be magnetic bearings, as shown schematically in Figure 3 or 4 or Figure 6.

Alternatively or in addition to one or other of these variants, the motorized device 3 may further comprise the bearing or bearings 27; 270; 27 ', 28; 280; 28 ', one or more additional bearings 29 as shown schematically in Figure 6 or 11. Advantageously, such additional bearings 29 are also magnetic bearings so as not to add friction or noise.

Referring to Figures 7 to 9b, there is described in more detail an embodiment of magnetic bearing such as the bearing 28 for a motorized device 3 according to the embodiment described. In Figures 7 and 8, the magnetic bearing is designated by the reference 28, but of course, this embodiment can be applied for a magnetic bearing 27 or for an additional bearing 29 when it is magnetic.

The magnetic bearing 27, 28, 29 comprises a predefined number of magnetic rings 61, 63. In particular, the magnetic bearing 27, 28, 29 comprises at least a first magnetic ring 61 mounted integral with the movable part 31 and at least one second magnetic ring 63 mounted integral with the fixed portion 33. For this purpose, the magnetic bearing 27, 28, 29 comprises for example two support rings 67 and 69 concentric. The support ring 67 forms an outer ring and the support ring 69 forms an inner ring disposed inside the outer support ring 67. The support rings 67, 69 may in particular be metallic.

Each first, respectively second, magnetic ring 61, 63 has two concentric faces of opposite poles. In other words, each first, respectively second, magnetic ring 61, 63 has a north pole face and a south pole face. The faces of opposite poles are schematized by hatching in opposite directions in FIGS. 3 to 11.

According to the embodiment illustrated in FIGS. 3 and 6 to 9b, the magnetic bearing 27, 28, or 29 is of annular or cylindrical shape, so that the faces of the first and second magnetic rings 61, 63 are faces. cylindrical.

In addition, the at least one first magnetic ring 61 may be mounted integral with the rotor 51 and the at least one second magnetic ring 63 may be mounted integral with the stator 53 (see Figures 3 to 6).

To do this, the first magnetic ring or rings 61 are fixed on the outer support ring 67, itself fixed to the rotor 51 in this example. Also, the second or second magnetic rings 63 are fixed on the inner support ring 69, itself fixed to the stator 53 in this example.

The first magnetic ring (s) 61 and the second magnetic ring (s) 63 are arranged with facing faces of the same pole, so as to push back mutually, as shown schematically by the arrows Fl, F2 in Figures 3 to 6. This keeps the rotor 51 levitated with respect to the stator 53.

In the example illustrated in Figures 7 to 9b, the or each second magnetic ring 63 is arranged in the or a first magnetic ring 61 associated, so that the facing faces of the first 61 and second 63 magnetic rings are likewise pole. In other words, if the outer face of the first magnetic ring 61 is north pole and its inner face is south pole, the face of the second magnetic ring facing the inner face of the first magnetic ring 61 is also south pole. Of course, the opposite is also true.

Preferably, the magnetic bearing 28, or 27 comprises an even number of first magnetic rings 61 and second magnetic rings 63. By way of non-limiting example as illustrated in the examples of Figures 3, 6, 7 and 8, the bearing magnetic 28, respectively 27, comprises two first magnetic rings 61 and two second magnetic rings 63. In other words, each magnetic bearing 28, 27 comprises for example two rows of first and second rings 61, 63 which are opposed. An even number of first and second magnetic rings could also be considered for the additional bearings 29.

Referring to Figure 8, two groups of magnetic rings 61, 63 are spaced by a gap ei, also called the first gap. Each group has a first magnetic ring 61 and a second magnetic ring 63.

The first gap ei is advantageously constant. It is conceivable to have an insulator in this first gap ei. The insulation may be a metal film or a metal ring to stop the magnetic flux so that it remains in the magnetic bearing 28, respectively 27, or 29.

Also, each first magnetic ring 61 is spaced from a second magnetic ring 63 by another gap e2, also called the second gap. The second air gap e2 is advantageously of the same value between all the first magnetic rings 61 and second magnetic rings 63.This indexing gaps ei and e2 only allows to differentiate without involving priority between these two gaps ei, β2. Of course, the air gaps ei and e2 can be provided independently of one another. In particular, it can be provided that each first magnetic ring 61 is spaced from a second magnetic ring 63 by a gap β2, without providing groups of magnetic rings 61, 63 spaced by a gap ei.

Moreover, in the example of FIGS. 2a, 3, 6 and 8, the bearing or bearings 27 or 27 'and 28 are arranged coaxially with the motor 5.

In particular, the faces of the magnetic bearings 27, 28 extend parallel to the faces of the rotor 51 and the stator 53. In other words, the faces of the bearings 27, 28, which in this example are cylindrical, extend in one direction. forming a zero angle with the axis of rotation A2 of the motor 5.

More precisely, in the particular example illustrated in FIG. 8, the magnetic bearing 28 is of annular or cylindrical shape, of which Taxe coincides with the axis of rotation A2 of the motor 5, and the first air gap ei corresponds to an axial air gap. Also according to this particular example of Figure 8, with the magnetic bearing 28 of annular or cylindrical shape whose Taxe coincides with A2 rotation axis of the motor 5, the second gap corresponds to a radial air gap.

In the particular case of an additional bearing 29 as represented in FIG. 6 and FIG. 11, a first magnetic ring 61 is arranged facing a second magnetic ring 63 with facing faces of the same pole, so as to repel each other, as shown schematically by arrows Fl, F2 (see Figure 6). The first magnetic ring 61 is spaced from the second magnetic ring 63 by an air gap (see FIG. 11). Unlike the embodiment variant previously described with reference to FIG. 8, the gap between the first and second magnetic rings 61, 63 corresponds to an axial air gap, and no longer radial.

Furthermore, in order to guarantee axial stability of the rotor 51 in levitation with respect to the stator 53 by virtue of the magnetic bearings 27, 270, 28, 280, at least one axial centering or stopping means such as an abutment can be provided. for example, in order to avoid a displacement of the rotor 51 in the longitudinal direction of the motor 5, as shown schematically by the double arrow F in FIGS. 3 to 6.

The axial centering can be obtained using at least one second bearing, in particular a second mechanical bearing, such as the bearing 27 'in the example illustrated in FIG. 2a or the bearing 28' in the example illustrated in FIG. FIG. 5. This gives a hybrid solution with at least one magnetic bearing 27; 270, or 28; 280 and at least one mechanical bearing 28 'or 27'.

As a variant (see FIG. 4) or in addition (see FIG. 5), at least one magnetic bearing 270, or even all of the magnetic bearings 270, 280 may have at least one part arranged obliquely with respect to the axis of rotation. A2 rotation of the motor 2. In this example at least one face extends at least partially in a direction oblique to the axis of rotation A2 of the motor 5.

To do this, according to the embodiment illustrated in Figures 4, 5 and 10, the magnetic bearing 270 or 280 may have at least one portion of conical shape. For example, the magnetic bearing 270, 280 is generally conical or frustoconical.

In Figure 10, the magnetic bearing is designated by the reference 280, but of course, this embodiment can be applied for a magnetic bearing 270 or for an additional bearing 29 when it is magnetic.

Only the differences of the magnetic bearings 270, 280 with respect to the bearings 27, 28 previously described are explained below.

According to the embodiment illustrated in Figures 4, 5 and 10, the magnetic bearing 270, 280, being of conical or frustoconical shape, the faces of the first (s) and second (s) magnetic ring 61, 63 are conical faces or frustoconical.

According to the particular example of FIGS. 4, 5 and 10, the faces of the first (s) and second (s) rings 61, 63 at the conical portion of each bearing 270, 280 extend in an oblique direction relative to to the axis of rotation A2 of the motor 5. For example, the face or faces of the first (s) and second (s) rings 61, 63 at the conical portion of the magnetic bearing 280, respectively 270, may extend in a direction inclined at an angle α less than 50 °, more precisely between 30 ° and 50 °, preferably of the order of 45 °, with respect to the axis of rotation A2 of the motor 5.

In the example of Figure 10, only one group of a first magnetic ring 61 and a second magnetic ring 63 is illustrated. Of course, alternatively and similarly to the embodiment of Figure 8, several groups of first and second magnetic rings 61, 63 may be provided, and may be spaced two by two of a gap ei.

In addition, similarly to the embodiment described with reference to FIG. 8, each first magnetic ring 61 is spaced apart from a second magnetic ring 63 by an air gap e2.

Moreover, in the case of several magnetic bearings 270, 280, or 29 (also referring to FIG. 6), the angle of inclination a can be chosen and adapted independently for each magnetic bearing 270, 280, or 29 In other words, the tilt angles have faces of the tapered portions of the magnetic bearings 270, 280, or 29 may be equal or different. Finally, the inclination angle has faces of the conical portions of one and / or the other of the magnetic bearings 270, 280, 29 may be adapted to promote the transverse force or the radial force according to the applications. Moreover, the angle of inclination a can be adapted according to the quality of the first (s) and second (s) magnetic rings so as to control the displacement of the rotor 51.

In addition, according to the variant shown in FIG. 4, the two magnetic bearings 270, 280 are advantageously arranged oppositely to a median plane of the motor 5, perpendicular to the axis of rotation A2 of the motor 5. This solution is particularly advantageous when the motorized device 3 comprises only magnetic bearings 270, 280 without additional mechanical bearing. Indeed, this opposite or herringbone arrangement of the magnetic bearings 270, 280 makes it possible to control the longitudinal displacement of the motor 5, more precisely of the rotor 51, without the need for additional parts and makes it possible to avoid the use of a mechanical bearing which would add friction and noise in operation.

Alternatively or additionally, the longitudinal displacement control of the motor 5, more precisely the rotor 51, is provided by the additional bearing or bearings 29 which are advantageously also magnetic bearings (see Figure 6). To do this, this (s) additional bearing (s) 29 is (are) arranged (s) to exert a constraint, here axially, to limit the axial displacement of the rotor 51. In the illustrated example , the additional bearing (s) 29 are arranged so that the faces of the first and second magnetic rings 61, 63 extend along an axis perpendicular to the axis of rotation A2 of the motor 5, vertical by 6. In addition, in the illustrated example, this (s) additional bearing (s) 29 is (are) arranged (s) around the lateral faces of the engine 5, here of the stator 53.

Thus, in the case of a motorized device 3 comprising an accessory 4 serving to protect the optics 14 of an optical sensor 13, during the rotational driving of the housing 6 and the optical element 9, the centrifugal force that the possible stains undergo is greater than the adhesion of these stains on the optical element 9. Any stains deposited on the outer surface of the optical element 9 are ejected from the optical element 9 and do not disturb the field of view V of the optical sensor 13. The use of one or more magnetic bearings 27, 270, 28, 280, 29 each comprising at least one first and at least one second magnetic rings 61, 63 arranged so that the magnetic fluxes oppose each other, as shown schematically by the arrows F1, F2, maintains the levitation of the rotor 51 driving the housing 6 and the optical element 9 relative to the stator 53, su pprimant friction problems due to the use of mechanical bearings such as ball bearings in the solutions of the prior art. This makes it possible to gain power and thus makes it possible to reduce the size of the motor 5. It has been found that with such a solution the size of the motor 5 can be halved for the same power as in the solutions of the art. previous using only mechanical bearings.

In addition, it is no longer necessary with such a magnetic bearing 27, 270, 28, 280, 29 to provide a lubrication of the bearing as in the solutions of the prior art with mechanical bearings, which avoids the problems of degassing lubricant and eliminates the risk of pollution inherent in this degassing.

Claims (3)

Motorized device (3) for a motor vehicle comprising an accessory (4) for a motor vehicle (100) rotatably mounted about an axis of rotation (A1) and a motor (5) configured to rotate the accessory (4), said motor (5) comprising a rotor (51) and a stator (53), the motorized device (3) comprising: - a fixed part (33) comprising the stator (53), and - a movable part ( 31) comprising the rotor (51) and the accessory (4) integral in rotation with the rotor (51), characterized in that the motorized device (3) further comprises at least one magnetic bearing (27, 270, 28, 280 , 29) arranged between the fixed part (33) and the movable part (31) of the motorized device (3), said at least one magnetic bearing (27, 270, 28, 280, 29) comprising at least a first magnetic ring ( 61) mounted integral with the movable part (31) and at least one second magnetic ring (63) mounted integral with the fixed part (33). 2. Device (3) according to the preceding claim, further comprising at least one mechanical bearing (27 ', 28'). 3. Device (3) according to any one of the preceding claims, wherein said at least one magnetic bearing (27, 270, 28, 280, 29) is arranged between the stator (53) and the rotor (51) of said motor (5). 4. Device (3) according to any one of the preceding claims, wherein said at least one magnetic bearing (27, 270, 28, 280, 29) comprises a predefined number of first and second magnetic rings (61, 63), each first and second magnetic ring (61, 63) having two concentric faces of opposite poles. 5. Device (3) according to any one of the preceding claims, wherein said at least one first magnetic ring (61) is spaced from said at least one second magnetic ring (63) by an air gap (ef). 6. Device (3) according to any one of the preceding claims, wherein said at least one magnetic bearing (27, 270, 28, 280, 29) comprises an even number of first magnetic rings (61) and second magnetic rings. (63). 7. Device (3) according to the preceding claim, wherein two first magnetic rings (61), respectively two second magnetic rings (63), are spaced by an air gap (ei). 8. Device (3) according to any one of the preceding claims, wherein said at least one magnetic bearing (27, 270, 28, 280, 29) comprises two concentric support rings (67, 69). 9. Device (3) according to any one of the preceding claims, wherein said at least one magnetic bearing (270, 280, 29) has at least one face extending in a direction oblique to the axis of rotation. (A2) of the engine (5). 10. Device (3) according to any one of the preceding claims, wherein the motor (5) is a hollow motor. 11. Device (3) according to any one of the preceding claims, wherein the accessory (4) is a means of protection of an optical sensor (13) of system (1) driving assistance, the accessory (4) comprising in particular an optical element (9) configured to be arranged upstream of an optic (14) of the optical sensor (13). 12. System (1) for driving assistance for a motor vehicle comprising an optical sensor (13) and a motorized device (3) according to any one of the preceding claims, the accessory (4) being a means of protecting the motor vehicle. optical sensor (13).