DEVICE FOR PROTECTING AN OPTICAL SENSOR AND CORRESPONDING DRIVER ASSISTANCE SYSTEM

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. The invention also relates to a method for assembling such a protection device.

[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 preferable 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 greatly 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 it, 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] Alternatively, the camera is housed in a protective device. However, such a protective device is very bulky to install. Reducing bulk is a constant goal in the automotive industry, particularly in the field of driver assistance.

[0007] A device for protecting an optical sensor of a driving assistance system for a motor vehicle is described in the publication referenced FR3058651.

[0008] The present invention proposes to at least partially overcome the above-mentioned drawbacks by presenting an alternative device for protecting an optical sensor making it possible to prevent the deposition of dirt on the optical sensor such as a camera, and the arrangement of which is optimized so as to reduce the size.

[0009] To this end, the invention relates to a device for protecting an optical sensor of a driving assistance system for a motor vehicle, the optical sensor comprising an optic, said device comprising: an optical element configured to be arranged upstream of the optics of the optical sensor and mounted to rotate about a first axis of rotation, and a motor, in particular an electric motor, configured to drive the optical element in rotation.

[0010] According to the invention, the motor comprises a rotor configured to rotate about a second axis of rotation intersecting with the first axis of rotation of the optical element.

[0011] Such an arrangement makes it possible to reduce the size of the protection device and in particular facilitates its installation in the same housing for its assembly on a motor vehicle.

[0012] The optical sensor protection device may further comprise one or more of the following features, taken separately or in combination: the second axis of rotation of the motor is substantially perpendicular to the first axis of rotation of the optical element; the optical element is at least partly transparent; the optical element is distinct from the optical sensor; the optical element is configured to be arranged relative to the optics of the optical sensor, such that the first axis of rotation of the optical element is parallel and coincident with the optical axis of the optical sensor; the optical element is configured to be arranged relative to the optics of the optical sensor, such that the first axis of rotation of the optical element is coincident with the optical axis of the optical sensor; said device comprises at least one means for transmitting the movement of the rotor of the motor to the optical element; the transmission means comprises at least two toothed wheels, including a first toothed wheel configured to be driven by the rotor of the motor and configured to drive a second toothed wheel;said device comprises a housing configured to receive the optical sensor and the motor; the optical sensor and the motor are received in the same housing of the housing; the housing is configured to receive said at least one transmission means; the optical sensor, the motor and said at least one transmission means are received in the same housing of the housing; said device further comprises a module for generating and / or projecting air onto at least one zone of the optical element; the air generation and / or projection module is configured to generate and project a flow of compressed air; the flow of compressed air is preferably of pressure less than 10 bars; the air generation and / or projection module is configured to generate a predetermined volume of air, for example of the order of 10 mL; the air generation and / or projection module comprises at least one air projection nozzle;the air projection nozzle is arranged fixed relative to the optical element; the air projection nozzle is arranged so as to project an air flow onto the central zone of the optical element; the air generation and / or projection module comprises at least one air generation member; said at least one air generation member is chosen from at least one piston, a pump, an air reservoir, a turbine; the air generation and / or projection module comprises at least one valve or solenoid valve; the air generation and / or projection module comprises at least one pump for generating an air flow and an air reservoir connected to the pump so as to store the air flow generated by the pump; the air generation and / or projection module further comprises at least one valve connected to the air reservoir and to the projection nozzle, making it possible to regulate the air flow to the projection nozzle at a predetermined air volume and pressure;the housing is configured to receive said at least one air generating member; at least one air generating member is received in the same housing as the optical sensor, and / or the motor, and / or said at least one transmission means; the optical element has at least one surface configured to be arranged in the field of vision of the optical sensor; the optical element has at least one surface that is at least partly planar or substantially planar configured to be arranged in the field of vision of the optical sensor; the optical element has at least one surface that is at least partly spherical or substantially spherical configured to be arranged in the field of vision of the optical sensor; the optical element has at least one surface that is at least partly aspherical configured to be arranged in the field of vision of the optical sensor; said at least one surface has an extent greater than or equal to that of the field of vision of the optical sensor;the optical element is arranged centered relative to the first axis of rotation. ;

[0013] The invention also relates to a driving assistance system comprising an optical sensor comprising an optic. According to the invention, said system comprises a device for protecting the optical sensor as defined above.

[0014] 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 [ Fig.1] (figure 1 ) schematically represents a motor vehicle comprising a driving assistance system according to the invention, the [ Fig.2] (figure 2 ) is a perspective view of an optical sensor protection device, the [ Fig.3] (figure 3 ) is an exploded view of the protection device of the [ Fig.2] (figure 2 ) on which a box receiving the various elements of said device has been removed, the [ Fig.4] (figure 4 ) is a schematic representation of an optical element and an air projection nozzle of said device, the [ Fig.5a] (figure 5a ) is a schematic representation of a side view of the optical element with a water drop, the [ Fig. 5b] figure 5b is a schematic representation of the optical element of the [ Fig.5a] figure 5a after projection of an air flow, the [ Fig.6a] (figure 6a ) is a schematic representation of an area of ​​the optical element subjected to the air flow, and the [ Fig.6b] (figure 6b ) is a schematic representation of the optical element and the surface subjected to the air flow after rotation of the optical element.

[0015] In these figures, identical elements have the same references.

[0016] The following embodiments 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 to only one embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0017] In the description, certain elements may be indexed, such as 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 over another and such names can easily be interchanged without departing from the scope of the present description. This indexing also does not imply an order in time.

[0018] There [ Fig.1] (figure 1 ) shows a motor vehicle 100 equipped with at least one driving assistance system 1 according to the invention.

[0019] The driving assistance system 1 comprises in particular at least one optical sensor 13 and a protection device 3 for the optical sensor 13 which is better visible on the [ Fig.2] et [Fig.3] (figures 2 et 3 ).

[0020] The optical sensor 13 is for example an optical sensor 13 for taking pictures such as a camera. It may be a CCD sensor (for "charged coupled device" in English, namely a charge transfer 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".

[0021] As can be seen better on the [ Fig.3] (figure 3 ), 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, for example for a so-called fish-eye optic.

[0022] It is also possible to provide a support 17 for the optical sensor 13. This support 17 is arranged at the rear of the optical sensor 13 on the side opposite the optics 14.

[0023] According to the illustrated embodiment, the optical sensor 13 is intended to be mounted in the protection device 3. More precisely, the optical sensor 13 and in particular its support 17 are intended to be mounted fixed in the protection device 3.

[0024] Furthermore, the protection device 3 may comprise a base 31 intended to be fixed to the housing 6' and on which the support 17 of the optical sensor 13 is fixed. For this purpose, an orifice 33 may be provided on the base 31 to receive an axis of the support 17.

[0025] According to the example illustrated on the [ Fig.1] (figure 1 ), the protective device 3 is mounted at the front of the motor vehicle 100 at a bumper. Of course, as a variant, the protective 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 one side of the vehicle, for example at a rearview mirror.

[0026] 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. Dispositif de protection

[0027] More specifically, referring again to the [ Fig.2] et [Fig.3] (figures 2 et 3 ), the protection device 3 comprises: at least one accessory 4 for motor vehicle 100 (also referring to the [ Fig.1] (figure 1 )), this accessory 4 being mounted mobile in rotation around a first axis of rotation A1 and having the function of protecting the optical sensor 13, and an actuator, more precisely a motor 5, in particular an electric motor, configured to drive the accessory 4 in rotation.

[0028] The protection device 3 is therefore a motorized device.

[0029] The protection device 3 advantageously further comprises a housing 6' ([ Fig.2 ] - figure 2 ) to contain or form a support for all the elements of the protection device 3. The housing 6' can also contain the optical sensor 13.

[0030] In particular, the protection device 3 may comprise a first subassembly and a second subassembly, assembled together and arranged in the housing 6'. The first subassembly may comprise the accessory 4. The second subassembly may comprise the motor 5. Accessoire

[0031] The accessory 4 or means of protection may be at least partially transparent.

[0032] According to the embodiment described, the accessory 4 comprises an optical element 9 (see [ Fig.2] et [Fig.3 ] - figures 2 et 3 ).

[0033] The optical element 9 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. To do this, the optical element 9 is intended to be arranged upstream of the optics 14 of the optical sensor 13. In the present document, the term upstream is defined relative to the optical axis 15 and relative 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.It is this optical element 9 which is subject to attacks from the outside, that is to say from splashes of water, pollutants, gravel as well as deposits of pollutants or traces of water.

[0034] This optical element 9 is advantageously dimensioned 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 at least partly transparent so as not to impair the efficiency of the optical sensor 13. This optical element 9 can be made of glass or a transparent plastic material such as polycarbonate. The optical element 9 has at least one surface 9a, 9b (see [ Fig.5a] et [Fig.5b ] - figures 5a, 5b ), here central, intended to be arranged at least partially opposite the optic 14. Referring again to the [ Fig.2] et [Fig.3] (figures 2 et 3 ), the optical element 9 has a peripheral rim 90 intended to at least partially surround the optic 14.

[0035] 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 is parallel, or even coincident with the optical axis 15 of the optical sensor 13.

[0036] According to the embodiment described, the optical element 9 is distinct from the optical sensor 13.

[0037] This optical element 9 has an optical axis 91.

[0038] According to the example illustrated with the protection device 3 mounted at the front of the vehicle 100, the optical element 9 is arranged at the front of the protection device 3 while being oriented towards the front of the motor vehicle 100. In other words, the optical element 9 is arranged at the front of the accessory 4, or 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 ([ Fig.1 ] - figure 1 ).

[0039] Of course, as a variant, the optical sensor 9 can be oriented towards the rear of the motor vehicle 100 or can be mounted on one side of the vehicle, for example at the level of a rearview mirror.

[0040] Furthermore, the optical element 9 is arranged so as to be driven in rotation by the motor 5, to allow cleaning of the optical element 9 by centrifugal effect. The optical element 9 is advantageously arranged so that its axis of rotation A1 is parallel, or substantially parallel, to the optical axis 15 of the optical sensor 13, when the protection device 3 and the optical sensor 13 are mounted in the housing 6'. Advantageously, the first axis of rotation A1 of the optical element 9 coincides with the optical axis 15 of the optical sensor 13. This first axis of rotation A1 is also parallel or even coincident with the optical axis 91 of the optical element 9.

[0041] The optical element 9 can be arranged centered relative to the first axis of rotation A1. This optical element 9 has in particular a symmetry of revolution relative to the first axis of rotation A1.

[0042] Furthermore, when the protection device 3 receiving the optical sensor 13 is mounted on the vehicle 100 (also referring to the [ Fig.1 ] - figure 1 ), the optics 14 and the optical element 9 advantageously protrude from an opening provided on the element 2 of the vehicle 100.

[0043] Furthermore, the optical element 9 may have at least one surface 9a, 9b configured to be arranged at least partly in the field of vision of the optical sensor 13. This surface 9a, 9b advantageously has an extent greater than or equal to that of the field of vision of the optical sensor 13.

[0044] According to one embodiment, this surface 9a, 9b is at least partly, or even totally, flat in the field of vision of the optics 14 of the optical sensor 13. The at least partly flat optical element 9 can be produced in a simple manner.

[0045] Alternatively, the at least one surface 9a, 9b is at least partly spherical or substantially spherical in the field of vision of the optical sensor 13.

[0046] According to yet another variant, the at least one surface 9a, 9b is at least partly aspherical in the field of vision of the optical sensor 13.

[0047] In particular, according to the embodiment described, the optical element 9 comprises an inner surface 9a and an outer surface 9b opposite each other. The surfaces 9a, 9b are better visible on the [ Fig.5a] et [Fig.5b] (figures 5a et 5b ). The internal surface 9a of the optical element 9 is the surface intended to be arranged directly opposite the optics 14 of the optical sensor 13.

[0048] Also referring to the [ Fig.2] et [Fig.3] (figures 2 et 3 ), the inner 9a and outer 9b surfaces are located partly or completely in the field of vision of the optical sensor 13 when the housing 6' houses the optical sensor 13. The inner surface 9a and the outer surface 9b may be parallel. The surfaces 9a, 9b are advantageously centered relative to the optical sensor 13, more precisely to the optics 14.

[0049] Furthermore, in order to avoid a condensation phenomenon between the optics 14 and the optical element 9, the internal surface 9a of the optical element 9 advantageously has an anti-fog property. In particular, the internal surface 9a of the optical element 9 has an anti-fog coating.

[0050] Alternatively or additionally, the inner surface 9a and / or outer surface 9b of the optical element 9 may have one or more of the following properties: hydrophobic, infrared filter, photocatalytic, super hydrophobic, lipophobic, hydrophilic, or even super hydrophilic, resistance to gravel, or any other surface treatment making it possible 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 off the outer surface without leaving any traces because the water will not be able to adhere to this outer surface. Thus, the layers or coatings on the outer surface 9b of the optical element 9 make it possible to limit the possibilities of adhesion of organic or mineral pollutants as well as the presence of traces of water on the optical element 9 which could impair the proper functioning of the driving assistance system 1.Advantageously, a liquid solution, such as a Rain-X ® type solution, can be deposited on the external surface 9b of the optical element 9 in order to form a hydrophobic film. These exemplary embodiments are provided for illustrative purposes and are not limiting. For example, a person skilled in the art can use a transparent optical element 9 having an external surface 9b having other properties making it possible to limit the adhesion of dirt to this external surface 9b without departing from the scope of the present invention.

[0051] Optionally, the optical element 9 may also include an integrated defrosting or demisting system to ensure good operability of the driving assistance system 1 regardless of weather conditions, such as a filament or a defrosting resistor for example.

[0052] Advantageously, at least one condensation limiting means, hereinafter called anti-condensation means (not shown in the figures), is provided. Such an anti-condensation means may be provided at the edge of the optical element 9 at least partially surrounding the optics 14. By way of non-limiting example, the anti-condensation means may comprise at least one through-orifice. Preferably, when several orifices are provided, they are arranged symmetrically with respect to the first axis of rotation A1 of the optical element 9. In addition, one or more semi-permeable membranes (not shown) may be provided, respectively arranged at least at the level of one orifice. These membranes are permeable to air and impermeable to water, thus promoting good ventilation between the optics 14 and the optical element 9 and thus preventing the accumulation of condensation.

[0053] Furthermore, according to an alternative embodiment not shown, the protection device 3 may further comprise a rotating housing secured to the optical element 9 intended to be driven in rotation by the motor 5 via the transmission means 7. This may in particular be a rotating housing capable of receiving at least partially the optical sensor 13. Motorisation

[0054] As for motor 5, it is advantageously a small, even miniature, electric motor.

[0055] 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.

[0056] 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 7g.

[0057] By way of non-limiting example, the motor 5 may more particularly be a brushless motor, also known as a “brushless motor” in English.

[0058] The motor 5 may have a rotational speed of between 1000 and 50000 rpm, preferably between 5000 and 20000 rpm, and more preferably between 7000 and 15000 rpm. Such rotational speeds allow the removal of any dirt that may have been deposited on the optical element 9 by centrifugal effect and thus allow the optics 14 of the optical sensor 13 to be kept clean to ensure optimized operation of the driving assistance system 1. According to a particularly advantageous embodiment described below, the rotational speed can be reduced to a speed of the order of 4000 to 5000 rpm.

[0059] The motor 5 is for example electrically powered by a power supply connected to the general electrical circuit of the vehicle 100 (also referring to the - [ Fig.1 ] - figure 1 ).

[0060] Referring again to the [ Fig.2] et [Fig.3] (figures 2 et 3 ), the motor 5 is rotatably mounted around a second axis of rotation A2. The motor 5 comprises a rotor 51 and a fixed stator 53, the rotor 51 being rotatable relative to the fixed stator 53. The rotor 51 has a rotary shaft 510. According to the illustrated embodiment, the stator 53 is arranged around the rotor 51. The stator 53 is therefore external and the rotor 51 internal.

[0061] The motor 5 is configured to drive the accessory 4 in rotation, namely in this example the optical element 9.

[0062] The motor 5, in particular the rotor 51, is rotatably mounted about a second axis of rotation A2. The motor 5 is arranged so that its axis of rotation A2 intersects with the first axis of rotation A1 of the optical element 9, and with the optical axis 15 of the optical sensor 13. More particularly, the motor 5 is arranged so that its axis of rotation A2 is perpendicular or substantially perpendicular to the first axis of rotation A1 of the optical element 9, and to the optical axis 15 of the optical sensor 13. Such an arrangement makes it possible to obtain a compact assembly received in the housing 6'.

[0063] In this case, the protection device 3 comprises at least one means 7 for transmitting the movement of the rotary shaft of the electric motor to the optical element. According to the example illustrated, the transmission means 7 comprises at least two toothed or cogwheels 71 and 73. A first cogwheel 71 is arranged so as to be able to rotate about the second axis of rotation A2. A second cogwheel 73 is arranged in engagement with the first cogwheel 71, and so as to be able to rotate about the first axis of rotation A1. The rotary shaft 510 is coupled to the first cogwheel 71 to drive it in rotation about the second axis of rotation A2. This first cogwheel 71 in turn drives the second cogwheel 73 about the first axis of rotation A1. The first toothed wheel 71 can be mounted on the base 31 with the interposition of a bearing, such as a ball bearing 75.

[0064] The second toothed wheel 73 is configured to drive the optical element 9 in rotation. In particular, another bearing, such as a ball bearing 77, may be provided between the second toothed wheel 73 and the optical element 9, in particular the peripheral rim 90 of the optical element 9. The second toothed wheel 73 has a central orifice for receiving at least part of the optical element 9 and the bearing 77.

[0065] For a compact arrangement, the second toothed wheel 73 can also be arranged around the optics 14 of the optical sensor 13. Module de génération et / ou de projection d'air

[0066] According to a particular embodiment, the protection device 3 further comprises an air generation and / or projection module 8. This module 8 is designed to generate and / or project at least one air flow onto at least one zone of the optical element 9. The air flow projected onto the optical element 9 is shown diagrammatically by the arrows F on the [ Fig.4] et [Fig.5b] (figures 4 et 5b ).

[0067] In particular, it is an air flow F compressed. The air flow F compressed is in particular of pressure less than 10 bars, for example between 1 bar and 2 bars, and preferably of the order of 1.5 bars.

[0068] The air generation and / or projection module 8 ([ Fig.2] et [Fig.3 ] - figures 2 et 3 ) is also configured to generate a predetermined volume of air, for example of the order of 10mL.

[0069] To do this, the air generation and / or projection module 8 comprises at least one air projection nozzle 81, visible on the [ Fig.2] et [Fig.3] (figures 2 et 3 ) and represented very schematically on the [ Fig.4], [Fig.5b] et [Fig.6a] et [Fig.6b] (figures 4 et 5b, et 6a, 6b ).

[0070] The air projection nozzle 81 is arranged fixed relative to the optical element 9. This air projection nozzle 81 is located above the optical element 9, with reference to the arrangement of the elements on the [Fig.2] à [Fig.4 And [Fig.5b] à [Fig.6b ] ( figures 2 à 4

[0071] And 5b à 6b ) which corresponds to the final arrangement on the motor vehicle. The air projection nozzle 81 is notably arranged close to the optical element 9.

[0072] The air projection nozzle 81 is further arranged to project the air flow F at least on the central area of ​​the optical element 9. In particular, the air projection nozzle 81 is arranged so as to project the air flow F on the central area and possibly on a lower area of ​​the optical element 9. The term lower is designated with reference to the arrangement of the elements on the [ Fig.6a] (figure 6a ). The lower zone corresponds to the zone furthest from the air projection nozzle 81. The entire zone of the external surface 9b of the optical element 9 onto which the air flow is projected F is referenced by Z1 and is represented schematically on the [ Fig.6a] (figure 6a ). The shape of the air projection nozzle 81 can be modified so as to adapt the air flow F. This representation of the area Z1 subjected to air flow F is very schematic, and in particular, the optical element 9 being mobile in rotation, it is clear that the area Z1 of the optical element 9 subjected to the air flow F is not the same during rotation.

[0073] According to the example illustrated, the air projection nozzle 81, in particular its end, may have a generally conical shape, as a result of which the air flow F projected reaches an area Z1 of the optical element 9, of generally triangular or “V” shape. In this example, the apex of the triangular shape is at or near the center of the external surface 9b of the optical element 9 and the base of the triangular shape at the lower part, with reference to the arrangement on the [ Fig.6a] (figure 6a ), of the external surface 9b of the optical element 9.

[0074] Referring to the [ Fig.5a] et [Fig.5b] (figures 5a et 5b ), the projection of the air flow F allows the ejection of small drops of water 10 which would remain in the center or substantially in the center of the optical element 9. The air flow F can be projected evenly onto the outer surface 9b of the optical element 9.

[0075] In particular, the air generation and / or projection module 8 can be implemented during the rotation of the optical element 9. In combination with the rotation of the optical element 9, all or almost all of the external surface 9b of the optical element 9 is swept by the air flow. F , as schematized by the circular zone Z2 on the[ Fig.6b] (figure 6b ).

[0076] The air flow Fadvantageously compressed air projected by the air projection nozzle 81 allows, in a manner complementary to the rotation of the optical element 9, to ensure optimized cleaning of the latter. Indeed, when approaching the center of the optical element 9, it may be that small drops of water or dirt located in the center or near the center of the optical element 9 are more difficult to remove because the rotation speed at the center may not be sufficient to eject them. Such a drop of water is shown diagrammatically and designated by the reference 10 on the [ Fig.5a] et [Fig.5b] (figures 5a et 5b ). To eliminate these small drops of water in the center, it is advisable to rotate at a very high speed, for example greater than 10,000 revolutions per minute. Alternatively, by projecting a small volume of compressed air, for example 10 ml of compressed air at 1.5 bars, for a certain duration, namely 100 ms in the case described to release the predetermined 10 ml of compressed air, the time to release this given volume of air, all or almost all of the external surface 9b of the optical element 9 passes one to several times, for example six to seven times, under the air flow F .

[0077] This makes it possible to eject not only the water drops 10 from the center of the external surface 9b of the optical element 9 but also those at the periphery. The air jet completing the rotation of the optical element 9 for cleaning the latter, the speed of the motor 5 can be reduced in particular to around 4000 to 5000 revolutions per minute.

[0078] Of course, the example of an air volume of 10 mL at a pressure of 1.5 bars is an illustrative and non-limiting embodiment. The volume and pressure values ​​can be adapted, in particular with a view to minimizing the protection device 3.

[0079] According to another embodiment, it is possible to envisage a continuous projection of air onto the external surface 9b of the optical element 9.

[0080] Furthermore, according to a variant not illustrated, the protection device 3 may comprise several projection nozzles, and in particular for projection of another fluid, such as cleaning liquid.

[0081] The air generation and / or projection module 8 also comprises at least one air generation member. This may be, for example, an external member that is not attached to the engine 5. Examples that may be mentioned, in a non-limiting and non-exhaustive manner, are one or more pistons, one or more pumps, one or more air tanks, or one or more turbines. The air generation and / or projection module 8 may also comprise one or more valves or solenoid valves.

[0082] According to the particular example illustrated on the [ Fig.2] et [Fig.3] (figures 2 et 3 ), the air generation and / or projection module 8 comprises: at least one pump 83 or micro-pump, for generating an air flow, and an air reservoir 85 connected to the pump 83 so as to store the air flow generated by the pump 83.

[0083] The air generation and / or projection module 8 also comprises in this example at least one valve or solenoid valve 87 connected to the air reservoir 85 and to the projection nozzle 81, making it possible to regulate and control the air flow to the projection nozzle 81, in particular to deliver a predetermined volume of air, for example 10 mL, at a predetermined pressure, for example 1.5 bars. The valve 87 or the solenoid valve makes it possible to release the air flow sequentially.

[0084] Of course, any other means for generating or producing an air flow can be considered. Any means for bringing this air and / or projecting this air onto the external surface 9b of the optical element 9 is also conceivable.

[0085] According to an alternative not shown, the motor 5 provided for the rotational drive of the optical element 9 can be used for the generation of the air flow. F to be projected onto the optical element 9. Boitier

[0086] Referring again to the [ Fig.3] (figure 3 ), the 6' housing is advantageously a waterproof 6' housing. The 6' housing can be made of any suitable material known to those skilled in the art.

[0087] This 6' housing is configured to receive the optical sensor 13 and the motor 5. In particular, the 6' housing can define a housing 60 receiving both the optical sensor 13 and the motor 5.

[0088] This housing 6' can also receive the means 7 for transmitting the movement of the rotary shaft 510 to the optical element 9. The transmission means 7 can be received in the same housing 60 as the motor 5 and the optical sensor 13.

[0089] As stated previously, the protection device 3 may comprise an air generating member, and in this case the housing 6' may receive this air generating member, in particular in the same housing as the optical sensor 13, the motor 5, and the transmission means 7.

[0090] According to the illustrated embodiment, the housing 60 also contains the pump 83, the air reservoir 85 and the valve or solenoid valve 87. Of course, the pump 83 and the air reservoir 85 can be remote, that is to say they may not be arranged in the housing 6' next to the optical sensor 13.

[0091] Furthermore, a sealed arrangement is advantageously provided at the level of the housing 6' 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.

[0092] Thus, in operation, the actuator, more precisely the motor 5, rotates the first toothed wheel 71 which in turn drives the second toothed wheel 73 in engagement with the optical element 9. The rotation of the optical element 9, possibly combined with the projection of a fluid, such as a flow of compressed air onto the external surface 9b of the optical element 9, ensures the elimination of dirt due to the centrifugal force to which the latter are subjected. The field of vision of the optical sensor 13 thus remains clear.

[0093] Furthermore, the production of this protection device 3 with an axis of rotation A2 of the motor 5 intersecting or even perpendicular to the axis of rotation A1 of the optical element 9, makes it possible to reduce the size of the protection device 3 and to obtain a very compact device 3. This in particular facilitates its mounting on the motor vehicle 100.

Claims

1. A device (3) for protecting an optical sensor (13) of a driver assistance system (1) for a motor vehicle (100), the optical sensor (13) comprising an optic (14), said device (3) including: - an optical element (9) configured to be positioned upstream of the optic (14) of the optical sensor (13) and rotatably mounted about a first axis of rotation (A1), and - an electric motor (5) configured to rotate the optical element (9), characterized in that the electric motor (5) comprises a rotor (51) configured to rotate about a second axis of rotation (A2) that intersects the first axis of rotation (A1) of the optical element (9).

2. The device (3) as claimed in the preceding claim, wherein the second axis of rotation (A2) of the electric motor (5) is substantially perpendicular to the first axis of rotation (A1) of the optical element (9).

3. The device (3) as claimed in any one of the preceding claims, wherein the optical element (9) is configured to be arranged with respect to the optic (14) of the optical sensor (13) so that the first axis of rotation (A1) of the optical element (9) is parallel to or coincident with the optical axis (15) of the optical sensor (13).

4. The device (3) as claimed in any one of the preceding claims, including at least one means (7) for transmitting the movement of the rotor (51) of the electric motor (5) to the optical element (9).

5. The device (3) as claimed in any one of the preceding claims, including a housing (6') configured to receive the optical sensor (13) and the electric motor (5).

6. The device (3) as claimed in any one of the preceding claims, wherein said device (3) further comprises a module (8) for generating and / or spraying air onto at least one region (Z1) of the optical element (9).

7. The device (3) as claimed in the preceding claim, wherein the air generating and / or spraying module (8) includes at least one air spray nozzle (81).

8. The device (3) as claimed in the preceding claim, wherein the air spray nozzle (81) is arranged so that it sprays an air jet (F) onto the central region of the optical element.

9. The device (3) as claimed in any one of the preceding claims 6 to 8, wherein the air generating and / or spraying module (8) comprises at least one air generating member, selected from at least a piston, a pump (83), an air reservoir, and an impeller.

10. The device (3) as claimed in any one of the preceding claims 6 to 9, wherein the air generating and / or spraying module (8) includes: - at least one pump (83) for generating an air jet, and - an air reservoir (85) connected to the pump (83) so as to store the air jet generated by the pump (83).