Protective device for an optical sensor.

Description

[0001] The present invention relates to the field of driving assistance and in particular to driving assistance systems installed on certain vehicles, the driving assistance system possibly comprising an optical sensor, such as for example a camera comprising a lens, in particular comprising at least one lens. More particularly, the invention relates to a device for protecting such an optical sensor.

[0002] Currently, front, rear, and side-view cameras are installed in a large number of motor vehicles. They are part of driver assistance systems, such as parking assistance systems and lane departure warning systems.

[0003] There are known cameras that are installed inside the passenger compartment of a vehicle against the rear window / window, aiming backwards from the rear window of the vehicle. These cameras are well protected from external climatic hazards and from dirt caused by organic or mineral pollutants. However, the viewing angle for such cameras, installed inside the passenger compartment, is not optimal, especially for parking assistance, because they do not allow you to see obstacles located near the rear of the vehicle, for example.

[0004] For this reason, it is preferred to install the cameras of driver assistance systems outside the vehicles in different locations depending on the intended use, for example on the rear or front bumper, or on the rear or front license plate of the vehicle. In this case, the camera is therefore highly exposed to splashes of mineral or organic dirt that can deposit on its optics and thus reduce its effectiveness or even render it inoperative. Especially in rainy weather, rain and dirt splashes can significantly affect the operability of the driver assistance system including such a camera. The surfaces of the camera optics must be cleaned to ensure their proper functioning.

[0005] To counter the deposit of dirt on the camera, it is known to arrange a device for cleaning the camera optics, generally a cleaning fluid nozzle, near the camera, to remove the pollutants that have been deposited over time. However, the use of these nozzles leads to an increase in the operating costs of such a driver assistance system because they require the use of fairly large quantities of cleaning fluid.

[0006] Recently, the applicant has developed another device for cleaning camera optics, which comprises a housing mounted to rotate about an axis of rotation and which has a housing configured to receive an optical sensor, an optical element secured to the housing, the optical element having at least one transparent surface arranged in the field of vision of the optical sensor and an actuator coupled to the housing to rotate the housing and the optical element and thus allow the removal of dirt by a centrifugal effect. Document WO2018 / 019662 discloses such a cleaning device.

[0007] Other examples of optical sensor protection devices are described in US2007217782 US2011181725 and KR200700347299.

[0008] The invention aims to protect an alternative to the cleaning device illustrated in this document, which is distinguished in particular in the shape of the actuator and its cooperation with the housing.

[0009] In this context, a first embodiment according to the invention relates to a device for protecting an optical sensor for a motor vehicle, said optical sensor comprising an optic, the device comprising: a housing mounted to rotate about an axis of rotation and having a housing configured to receive the optical sensor, an optical element secured to the housing and configured to be arranged in the field of vision of the optical sensor, and an actuator coupled to the housing to drive the housing and the optical element in rotation, the actuator comprising a rotor and a stator configured so that the actuator is an internal rotor motor, the protection device being characterized in that the housing is directly fixed to the rotor and in that the rotor comprises three successive portions forming an actuating portion carrying a magnetic mass, a guide portion and a drive portion securely connected to the housing.

[0010] Preferably, at least a portion of the rotor extends within a volume defined by the stator, said at least portion of the rotor carrying a magnetic mass.

[0011] Advantageously, the invention thus makes it possible to arrange the rotating part in the center of the motor, which makes it possible to reduce the noise and unbalance induced by the rotation of the rotor carrying a magnetic mass.

[0012] This characteristic is accompanied in particular by a stepped profile of the rotor and, where appropriate, an intermediate part associated with this rotor, in order to allow one end to be integral in rotation with the housing which must be large enough to surround the optical sensor and at the opposite end to be as close as possible to the axis of rotation of the housing in order to reduce the overall size of the actuator.

[0013] The housing may be directly fixed to the rotor. In this case, the rotor may comprise three successive portions forming an actuating portion carrying a magnetic mass, a guiding portion and a driving portion integrally connected to the housing. Preferably, the driving portion has an average diameter of a value greater than the value of the average diameter of the actuating portion. Preferably, such a rotor is in a single piece.

[0014] A second embodiment according to the invention relates to a device for protecting an optical sensor for a motor vehicle, said optical sensor comprising an optic, the device comprising: a housing mounted to rotate about an axis of rotation and having a housing configured to receive the optical sensor, an optical element secured to the housing and configured to be arranged in the field of vision of the optical sensor, and an actuator coupled to the housing to drive the housing and the optical element in rotation, the actuator comprising a rotor and a stator configured so that the actuator is an internal rotor motor, the protection device being characterized in that it comprises an intermediate part forming a connection between the housing and the rotor, in that the rotor comprises an actuating portion carrying a magnetic mass and in that the intermediate part comprises a drive portion (513) securely connected to the housing and a guide portion connecting the drive portion to the actuating portion of the rotor.

[0015] The intermediate part may further have a covering crown extending the guide portion and covering one of the ends of the stator.

[0016] According to various characteristics of the invention, taken alone or in combination, it can be provided that: the actuator is a hollow motor; the optical sensor is extended at one axial end by a support tail housed at least partially inside the rotor internal to the hollow motor; the protection device comprises a movable part and a fixed part, the movable part comprising at least the rotor and the housing, and the fixed part comprising at least the stator, and the protection device comprises at least one bearing, preferably two, arranged between the movable part and the fixed part; at least one of the bearings is arranged between the rotor and the support tail; the stator comprises a transverse wall perpendicular to the axis of rotation of the housing and arranged opposite the optical element, the transverse wall comprising a sleeve for receiving one end of the support tail.

[0017] The invention also relates to a driving assistance system comprising an optical sensor comprising an optic. According to the invention, said system further comprises a device for protecting the optical sensor as defined above.

[0018] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given as an illustrative and non-limiting example, and the appended drawings among which: there figure 1 schematically represents a motor vehicle comprising a driving assistance system according to the invention, the figure 2 is a perspective view of a protection device for an optical sensor of the assistance system of the figure 1 , there figure 3 is a partial longitudinal sectional view of the protection device of the figure 2 according to a first embodiment, the figure 4 is a partial longitudinal sectional view of the protection device of the figure 2 according to a second embodiment.

[0019] There figure 1 shows a motor vehicle 100 equipped with at least one driving assistance system 1 according to the invention. The driving assistance system 1 comprises in particular at least one optical sensor 13 and a protection device 3, better visible on the figures 2 à 4 , surrounding the optical sensor 13.

[0020] According to the example illustrated on the figure 1 , the driving assistance system 1 is mounted at the front of the vehicle 100 at a bumper. Of course, as a variant, the protection device 3 can be mounted at the rear of the 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 rearview mirrors.

[0021] The protective device 3 can be fixed using any known technique, to any element 2 of the vehicle 100, such as a bodywork element or an exterior element such as a bumper, a rearview mirror or a license plate. For this purpose, a clip system, a screwing system, or even a bonding system can be mentioned, but not limited to.

[0022] The protective device 3 is configured and sized to receive and house the optical sensor 13.

[0023] The optical sensor 13 is, for example, an optical image capture sensor such as a camera. It may be a CCD sensor (for "charged coupled device") or a CMOS sensor comprising a matrix of miniature photodiodes. According to another variant, it may be a sensor for laser remote sensing called a LIDAR sensor, an acronym in English for "light detection and ranging".

[0024] As can be seen better on the figure 2 , the optical sensor 13 comprises an optic 14 with an optical axis 15. The optic 14 is for example an objective. A lens may comprise at least one lens, in particular several lenses depending on the field of vision and the resolution, for example between two and ten lenses, generally four or five lenses, or even ten lenses in the case of a so-called fish-eye optic. At least one of the lenses of the optic 14 is for example convex (domed) with convexity oriented towards the outside of the optical sensor 13, such as a so-called fish-eye optic.

[0025] The optics 14 is mounted at a first end, namely the front end, of a sensor body 16 in which an electronic unit 160 for controlling the optics is arranged. Furthermore, the sensor body is extended axially, i.e. in the direction parallel to the optical axis 15, towards the rear, i.e. opposite the optics 14, by a support-forming part 17 (visible in the figures 3 et 4 ) of the optical sensor 13.

[0026] The support 17 has a shape of revolution around the optical axis 15, with a base 170 fixed on the sensor body 16 and a support tail 171 which axially extends the base. The support tail 171 is hollow and it allows the passage of cables connecting the electronic unit 160 for controlling the optics to a network of the vehicle by means of cables not shown here.

[0027] The protection device 3 comprises at least one accessory 4 mounted to rotate about an axis of rotation A1 and having the function of protecting the optical sensor 13, and an actuator, more precisely a motor 5, configured to drive the accessory 4 in rotation. The protection device 3 is therefore a motorized device.

[0028] The accessory 4 of the protection device 3 comprises a housing 6 and an optical element 9 secured to the housing 6, with in the illustrated embodiments an optical element 9 made in a single piece with the housing 6. Alternatively, the housing 6 and the optical element 9 can be made by two separate pieces secured together.

[0029] The optical element 9 and the housing 6 are described in more detail below.

[0030] As regards the housing 6, it is mounted to be mobile in rotation around an axis of rotation A1 which is substantially parallel, if necessary merged with the optical axis 15.

[0031] Preferably, the housing 6 is a waterproof housing. The housing 6 may be made of any suitable material known to those skilled in the art.

[0032] More precisely, this housing 6 is arranged so as to be driven in rotation by the motor 5, which allows the rotation of the optical element 9. The optical element 9 is therefore, in this particular example, configured to be driven in rotation with the housing 6, so as to allow cleaning of the optical element 9 by centrifugal effect.

[0033] The optical element 9 is configured to be arranged at the front of the housing 6. The front of the housing 6 means the part of the housing 6 intended to face the road scene of which the optical sensor 13 participates in the shooting, when the protection device 3 is mounted on the vehicle 100 (also referring to the figure 1 ). In contrast, the rear of the housing 6 means the part of the housing 6 opposite the front of the housing 6 and is therefore the part furthest from the road scene in which the optical sensor 13 participates in taking pictures.

[0034] As illustrated, the optical sensor 13 is mounted in the protection device so that the sensor body 16 is housed at least partly in the housing 6 while the optics 14 are opposite the optical element 9. To do this, the housing 6 is configured so as to form a housing 19 (see figure 3 ) sized to receive the optical sensor 13, for example so that the optical axis 15 of the optical sensor 13 coincides with the axis of rotation A1 of the housing 6.

[0035] More precisely, the housing 6 comprises a wall 21 defining the housing 19 for the optical sensor 13. This wall 21 can be centered around the axis of rotation A1 of the optical element 9 and the housing 6. In this example, the wall 21 is of a substantially cylindrical general shape.

[0036] According to a first variant, the wall 21 can be made in a single piece with the optical element 9. According to a second variant, the wall 21 and the optical element 9 can be made by two separate pieces, and in this case the optical element 9 is made integral with the wall 21 at a front end of the latter. By way of non-limiting example, the connection between the wall 21 and the optical element 9 can be made by ultrasonic welding. Thus, the housing 6 and the optical element 9 can be made in one or more pieces. 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.

[0037] The optical element 9, for its part, is intended to protect the optics 14 of the optical sensor 13 from possible projections of dirt or solid debris which could damage this optics 14. It is therefore a protective element, or more precisely a protective mask for the optical sensor 13, and it is this optical element 9 which is subjected to attacks coming from the outside, that is to say from projections of water, pollutants, gravel as well as deposits of pollutants or traces of water.

[0038] According to the embodiment described, the optical element 9 is distinct from the optical sensor 13.

[0039] This optical element 9 has an optical axis 91.

[0040] The optical element 9 is arranged at the front of the protection device 3. In other words, the optical element 9 is arranged at the front of the housing 6. The front of the protection device 3 means the part intended to face the road scene of which the optical sensor 13 participates in the shooting, when the protection device 3 is mounted on the vehicle 100 ( figure 1 ). In contrast, the rear of the protection device 3 is the part opposite the front and the optical element 9; it is therefore the part furthest from the road scene in which the optical sensor 13 participates in taking pictures.

[0041] The optical element 9 is intended to be arranged upstream of the optical sensor 13, more precisely upstream of the optics 14 ( figures 2 And 3). In this document, the term upstream is defined in relation to the optical axis 15 and in relation to the road scene in which the optical sensor 13 participates in the shooting. In other words, “upstream” of the optics 14 means a position in which the optical element 9 is arranged between the optics 14 and the road scene in which the optical sensor 13 participates in the shooting, along the optical axis 15.

[0042] This optical element 9 is advantageously sized so as to cover the entire surface of the optics 14. The optical element 9 is therefore arranged in the field of vision of the optical sensor 13. For this purpose, the optical element 9 is advantageously transparent so as not to impair the efficiency of the optical sensor 13. This optical element 9 can be made of glass or of a transparent plastic material such as polycarbonate.

[0043] The optical element 9 can be arranged centered relative to the optical sensor 13, more precisely centered relative to the optics 14. The optical element 9 is arranged so that its optical axis 91 coincides with the optical axis 15 of the optical sensor 13.

[0044] As stated previously, the optical element 9 is integral with the housing 6, it is therefore integral in rotation with the housing 6. Thus, the optical element 9 is also mounted mobile in rotation about the axis of rotation A1. More precisely, the housing 6 can be arranged so as to be driven in rotation by the motor 5, which allows the rotation of the optical element 9. The optical element 9 is therefore configured to be driven in rotation with the housing 6, so as to allow cleaning of the optical element 9 by a centrifugal effect.

[0045] Advantageously, the axis of rotation A1 of the optical element 9 coincides with the optical axis 15 of the optical sensor 13. This axis of rotation A1 also coincides with the optical axis 91 of the optical element 9.

[0046] The optical element 9 can be arranged centered relative to the axis of rotation A1. This optical element 9 has in particular a symmetry of revolution relative to the axis of rotation A1.

[0047] Furthermore, when the protection device 3 receiving the optical sensor 13 is mounted on the vehicle 100 (also referring to the figure 1 ), the optics 14 and the optical element 9 advantageously protrude from an opening provided on the element 2 of the vehicle 100.

[0048] We will now describe the engine 5 in more detail, with particular reference to a first embodiment illustrated in the figure 3 and a second embodiment illustrated in the figure 4 .

[0049] The motor 5 is assembled at the rear of the housing 6, that is to say on the side opposite the optical element 9. More particularly, the motor 5 is arranged in the extension of the optical sensor 13. This forms a sealed block, thus preventing the introduction of dirt inside the housing 6 intended to receive the optical sensor 13. A sealed arrangement can be provided at the rear of the motor 5 for the passage of cables or wires in order to limit the entry of water vapor and / or other contaminants inside the protection device 3.

[0050] Motor 5 can in particular be a small or even miniature electric motor.

[0051] By small electric motor is meant in the context of the present invention a stepper motor, an actuator, a direct current motor with or without brushes, an asynchronous motor or a synchronous motor, the mass of which is less than 10 kg, or even less than 1 kg, in particular used to operate equipment for vehicles.

[0052] By miniature electric motor is meant in the context of the present invention a stepper motor, an actuator, a direct current motor with or without brushes, an asynchronous motor or a synchronous motor, the mass of which is less than 200g, or even less than 100g, preferably between 30g and 100g, for example between 30g and 60g.

[0053] The motor 5 comprises a rotor 51 and a fixed stator 53, the rotor 51 being movable in rotation relative to the fixed stator 53. By way of non-limiting example, the motor 5 may more particularly be a brushless motor, also known as a “brushless motor” in English.

[0054] The motor 5 is fixed to a structural element of the vehicle not shown here, by means of the stator and this motor 5 is coupled to the housing 6 to drive the housing 6 and the optical element 9 in rotation. The housing 6 and the optical element 9 are integral with the rotor 51 of the motor 5.

[0055] The motor 5 is thus configured and sized to drive the housing 6 and the optical element 9 secured to the housing 6 in rotation.

[0056] The motor 5 is rotatably mounted about an axis of rotation A2. The motor 5 is for example 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, as well as with the optical axis 91 of the optical element 9.

[0057] The motor 5 is advantageously a hollow motor 5. It can receive at least in part the optical sensor 13 and more particularly the support tail 17. In this way, the hollow motor 5 can be crossed by the support tail and therefore, as described previously by cables connecting the electronic unit 160 for controlling the optics to a network of the vehicle.

[0058] According to the invention, the motor 5 is an internal rotor motor, that is to say that the stator 53 is arranged around at least part of the rotor 51.

[0059] According to the invention, the rotor 51 is hollow and provides a central passage for the support tail 17. A clearance is provided between the external surface of the support tail and the internal face delimiting the central passage of the rotor 51, in order to allow the rotation of the rotor 51 around the support tail 17.

[0060] In the illustrated examples, the motor 5 comprises at least one magnet 55 integral in rotation with the rotor 51, and a predefined number of electromagnetic coils 57, in particular at least four electromagnetic coils 57 mounted on the stator 53. The electromagnetic coils 57 are intended to be powered to enable the magnet 55 integral with the rotor 51 to be driven. For this purpose, the motor 5 comprises a control circuit 59 for powering the electromagnetic coils 57. This control circuit 59 can be connected to an electrical power supply harness 61 connected to the general electrical circuit of the vehicle 100 (referring to the figure 2 ).

[0061] It follows from the above and from the description common to the different embodiments that the protection device 3 comprises a movable part 31, also called rotating part 31, and a fixed part 33 (see figure 3 ).

[0062] The mobile part 31 comprises on the one hand at least the rotor 51 of the motor 5, and on the other hand at least one mobile element integral in rotation with the rotor 51, such as in particular the housing 6 and the associated optical element 9.

[0063] Furthermore, the fixed part 33 comprises on the one hand at least the stator 53 of the motor 5 and on the other hand at least one element or support fixed to the stator 53. In the example illustrated, the fixed part 33 of the motorized device 3 comprises the support tail 17 secured to the optical sensor 13, this support tail 17 being fixed to the stator 53.

[0064] In order to ensure the rotation of the movable part 31, the protection device 3 may comprise in particular one or more bearings 27, 28 shown schematically in the figures 3 et 4 In the examples illustrated, without being limiting, the protection device 3 comprises two bearings 27, 28.

[0065] These bearings 27, 28 are each arranged between the movable part 31 and the fixed part 33 of the protection device 3. The bearings 27, 28 are of a substantially annular general shape. In addition, the two bearings 27, 28 are arranged concentrically with the motor 5.

[0066] A first embodiment of the protection device is illustrated in detail on the figure 3 .

[0067] The stator 53 comprises a peripheral wall 530 forming a cylinder centered on the axis of rotation A2 and a transverse wall 531 which extends substantially perpendicularly the peripheral wall and which axially delimits the stator at one end of this peripheral wall.

[0068] The transverse wall has an orifice centered on the axis of rotation A2 of the motor and sized to allow passage to the support tail 17 secured to the optical sensor. This orifice is bordered by a sleeve 532 which extends the transverse wall 531 towards the inside of the motor. This sleeve 532 is notably configured to allow the stator to be fixed to the support tail 17. The sleeve surrounds the free end of the support tail, opposite the optical sensor. The fixing between these two elements is a fixing by tight fitting, or by welding without this being exhaustive since the stator and the support tail together form part of the fixed part 33.

[0069] As illustrated, the sleeve 532 can serve as a support for a control circuit 59 for powering the electromagnetic coils 57.

[0070] Rotor 51 has a stepped shape with three distinct portions.

[0071] A first portion of the rotor, arranged inside the volume defined by the stator, consists of an actuating portion 511, carrying the magnet 55 allowing the rotor to rotate inside the stator. This first portion has a first diameter whose value is a function of the value of the diameter of the support tail 17, in order to allow rotation around this fixed element formed by the support tail and to allow the smallest possible size of the motor.

[0072] A second portion of the rotor, extending partly inside the volume defined by the stator and partly outside it, consists of a guide portion 512, on which rest the bearings facilitating the rotational guidance of the rotor inside the stator. This second portion may, if necessary, as illustrated in the figure 3 , have a shoulder forming stop surfaces for positioning the bearings. This second portion has a second average diameter whose value is greater than the value of the first diameter of the actuating portion 511, thereby forming a step between the actuating portion and a third portion of the rotor.

[0073] The third portion of the rotor, arranged outside the volume defined by the stator, consists of a drive portion 513, secured at its free end to the rear end of the accessory 4, here the free end of the housing 6. This third portion has a third diameter whose value, greater than the value of the second portion of the rotor, is a function of the value of the diameter of the housing 6, in order to allow the rotor and the housing to be secured to rotate in order to eliminate dirt.

[0074] In this embodiment, the two bearings are arranged in the area of ​​the guide portion 512 of the rotor 51. A first bearing 27 is arranged inside the rotor, between the internal face of the guide portion and the support tail 17, while a second bearing 28 is arranged substantially in the same area, this time in contact with the external surface of the guide portion 512, between this guide portion and the internal face of the peripheral wall of the stator.

[0075] A second embodiment of the protection device is illustrated in detail in the figure 4 , and this second embodiment differs from the first embodiment in particular in that the sleeve 532 which extends the transverse wall 531 of the stator is here turned outwards. As previously, the sleeve 532 surrounds the free end of the support tail 17 and the two elements are made integral.

[0076] The above results in a saving of space in the area opposite the internal face of the transverse wall, and the second bearing 28 is in this embodiment arranged in this area. More particularly, the second bearing 28 is arranged between the support tail 17 and a crown 510 formed at the end of the rotor arranged opposite the transverse wall 531 of the stator, the crown 510 having a larger diameter than the rest of the actuating portion 511 of the rotor housed in the internal volume of the stator as previously described. In this way, the two bearings 27, 28 are spaced apart from each other and advantageously arranged close to the axial ends of the rotor, which improves the rotational guidance performance and therefore the performance of the motor. This improvement also makes it possible to use smaller bearings, which has the advantage of reducing the mechanical friction between the rotor and the support tail 1.

[0077] In this second embodiment, the motor 5 differs in particular in that the rotor 51 is not directly connected to the housing 6, but by means of an intermediate part 54.

[0078] As illustrated, it is the intermediate part 54 which comprises the guide portion 512 and the drive portion 513 connected to the housing 6. In this second embodiment, the intermediate part 54 also comprises a covering ring 540 which extends the guide portion 512 to cover the open end of the stator, opposite the transverse wall 531.

[0079] The intermediate part is welded onto the rotor and forms with it a rotating assembly to drive the housing 6 and the optical element 9.

[0080] Advantageously, this intermediate part can be made of a material different from that of the rotor, which can improve the fixing of the bearing 27 arranged between the internal face of the guide portion 512 and the support tail 17.

[0081] Such an optical sensor protection device having an internal rotor motor has the advantage of having a magnet 55 arranged inside the space defined by the electromagnetic coils 57 of the stator, which makes it possible to use a magnet of limited size and therefore to reduce the mass of the protection device.

[0082] In operation, the actuator, more precisely the motor 5, rotates the housing 6 and the optical element 9 secured to the housing 6, relative to the optical sensor 13. The rotation of the housing 6 and the optical element 9 ensures the elimination of dirt due to the centrifugal force to which the latter are subjected. The field of vision V of the optical sensor 13 is thus always clear and clean.

[0083] The magnetic mass, i.e. the magnet 55, is integral with the internal rotor according to the invention. This configuration is particularly advantageous in that the unbalance created by the rotation of the magnetic mass is arranged as close as possible to the axis of rotation of the motor. The noise generated by the rotation of the magnet is thus reduced.

[0084] The preceding description clearly explains how the invention makes it possible to achieve the objectives it has set itself and in particular to propose an optical sensor protection device which allows effective cleaning of a sensor of a driving assistance system, in particular with reduced bulk and operating noise.

[0085] The invention is not limited to the embodiments specifically given in this document as non-limiting examples, and extends in particular to all equivalent means and to any technically effective combination of these means. Thus, the characteristics, variants and different forms of the embodiments of the invention may be associated with each other, in various combinations, to the extent that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of the characteristics described, provided that, in accordance with the invention, the protection device comprises an internal rotor motor according to the claims.

Claims

1. A device (3) for protecting an optical sensor (13) for a motor vehicle (100), said optical sensor (13) comprising an optic (14), characterized in that the device (3) includes: - a casing (6) mounted rotatably about a rotation axis (A1) and having a housing (19) configured to receive the optical sensor (13), - an optical element (9) attached to the casing (6) and configured to be placed in the field of vision of the optical sensor (13), and - an actuator (5) coupled to the casing (6) in order to rotate the casing (6) and the optical element (9), the actuator (5) including a rotor (51) and a stator (53) which are configured such that the actuator is a motor having an internal rotor, the protecting device (3) being characterized by the casing (6) is fixed directly on the rotor (51) and in that the rotor (51) three successive portions forming an actuating portion (511) carrying a magnetic mass (55), a guide portion (512) and a drive portion (513) attached to the casing (6).

2. The protecting device (3) as claimed in claim 1, characterized in that at least part of the rotor (51) extends inside a volume defined by the stator (53), said at least part of the rotor (51) carrying a magnetic mass (55).

3. The protecting device (3) as claimed in claim 1 or 2, characterized in that the drive portion (513) has an average diameter with a value greater than the value of the average diameter of the actuating portion (511).

4. The protecting device (3) of an optical sensor (13) for a motor vehicle (100), the said optical sensor (13) - a casing (6) mounted rotatably about a rotation axis (A1) and having a housing (19) configured to receive the optical sensor (13), - an optical element (9) integral with the casing (6) and configured to be placed in the field of vision of the optical sensor (13), and - an actuator (5) coupled to the casing (6) to rotate the casing (6) and the optical element (9), the actuator (5) including a rotor (51) and a stator (53) configured such that the actuator is a motor having an internal rotor the protecting device (3) being characterized in that it includes an intermediate piece (54) forming a link between the casing (6) and the rotor (51). in that the rotor (51) includes an actuating portion (511) carrying a magnetic mass (55) and in that the intermediate piece (54) includes a drive portion (513) attached to the casing (6) and a guide portion (512) linking the drive portion to the actuating portion of the rotor.

5. The protecting device (3) as claimed in the preceding claim, characterized in that the intermediate piece (54) has an overlapping ring (540) extending the guide portion (512) and overlapping one of the ends of the stator.

6. The protecting device (3) as claimed in one of the preceding claims, characterized in that the actuator (5) is a hollow motor.

7. The protecting device (3) as claimed in the one of the preceding claims, characterized in that the optical sensor (13) is extended at one axial end by a support shank (17) housed at least partially inside the rotor (51) internal to the hollow motor.

8. The protecting device (3) as claimed in one of the preceding claims, characterized in that it includes a mobile part (31) and a fixed part (33), the mobile part (31) including at least the rotor (51) and the casing (6), and the fixed part including at least the stator (53) and characterized in that it includes at least one rolling bearing (27, 28), preferably two, arranged between the mobile part (31) and the fixed part (33).

9. The protecting device (3) as claimed in the preceding claim, in combination with claim 7, characterized in that at least one of the rolling bearings (27, 28) is arranged between the rotor (51) and the support shank (17).

10. The protecting device (3) as claimed in one of the preceding claims, in combination with claim 7, characterized in that the stator (53) includes a transverse wall (531) perpendicular to the rotation axis of the casing and placed in the opposite direction to the optical element (9), the transverse wall including a sleeve (532) for receiving an end of the support shank (17).

11. A driving assistance system including an optical sensor and a device for protecting the optical sensor as claimed in one of the preceding claims.