Mechatronic electrical assistance module

Abstract

The present invention relates to a mechatronic electrical assistance module (1) including an electric motor (10) formed by a rotor (11) and a stator having a plurality of wound teeth as well as a differential position sensor (400) which is located between two constituent mechanical assemblies and provides a signal representative of the torque exerted between these mechanical assemblies, the mechanical assemblies being a drive means (100) and a hub (200), one of the mechanical assemblies being rigidly connected to the rotor (11). The position sensor (400) is associated with an assembly (300) that is deformable in the transverse plane and connected to the hub (200) at two to eight connection points (321, 322, 323) and to the external drive means (100) by at least two connection points (311, 312, 313).

Description

Mechatronic electric assistance module Field of invention

[0001] The present invention relates to the field of light electrically assisted pedal vehicles and more specifically to that of pedals providing information on the power exerted by the user on the pedals and integrating for this purpose a pedaling sensor. The pedaling sensor is the element which transmits the information on pedaling to the computer. Pedaling sensors are important elements of the electric bicycle insofar as they control the level of assistance that the bicycle will provide and therefore its autonomy. The user naturally adapts the speed of the bicycle to have ergonomic pedaling at the desired energy expenditure.

[0002] The electric motor starts when the user presses the pedal. The pedal sensor measures the torsional deformation of the crank axle to deduce the torque it is subjected to and therefore the pedaling power. Many pressure sensors also include a rotation sensor and become force sensors by combining the two pieces of information. By measuring the torque and rotation speed, the computers are able to analyze the situation more precisely and provide more proportional assistance depending on the effort. State of the art

[0003] Known from the state of the art is international patent application WO2021219199 describing a robotic arm comprising a drive motor with a drive shaft rotatable relative to a central axis of rotation, a base support and a measuring system for measuring a torque (M) acting inside the drive device. The measuring device has a spoked wheel with a hub, a radial outer ring and a plurality of spokes. The deformation of these spokes which connect the hub to the outer ring makes it possible to measure the torque, either the hub or the outer ring being permanently connected to the base support.

[0004] Disadvantages of the prior art

[0005] The prior art solution proposes to use the deformation of the spokes of a spoked wheel, placed coaxially around the central axis, between the hub and the outer ring, to calculate the torque, captured by sensors located on the spokes. These sensors detect variations in length or compression within the spokes. The radial deformation is not directly representative of the torque because it can be disturbed by linear, rather than angular, forces acting in the transverse plane of the spoked wheel. Furthermore, a torque acting on the spoked wheel results in a tangential component and a radial component, and only the radial component will be measured by the sensors. This results in poor sensitivity, limited resolution, and irregular variation of the signal as a function of the angular torque. Solution provided by the invention

[0006] The present invention generally relates to a mechatronic electrical assistance module having the characteristics set out in claim 1.

[0007] This mechatronic module comprises an electric motor formed by a rotor and a stator having a plurality of wound teeth as well as a differential position sensor interposed between two mechanical assemblies and providing a signal representative of the torque exerted between these mechanical assemblies, said mechanical assemblies being a drive means and a hub, one of the mechanical assemblies being integral with said rotor, characterized in that said position sensor is associated with an assembly deformable in the transverse plane, linked to said hub at 2 to 8 connection points, and to the external drive means by at least 2 connection points.

[0008] The mechatronic electrical assistance module according to the invention may also comprise, in a non-limiting manner, the following characteristics taken individually or in combination: at least part of said connection points has a degree of freedom in axial rotation, said deformable assembly is deformable in flexion, said deformable assembly is constituted by a radially undulating crown having a plurality of portions connecting an outer arc to an inner arc each having an inflection point, and in particular part of said outer arcs may be free with respect to said outer drive means and in this case the connections with said outer drive means are made by connection points with a degree of freedom in axial rotation and in this case, said hub may be connected to said inner arcs by connection points with a degree of freedom in axial rotation, and furthermore said outer arcs,free with respect to said external drive means, have a width greater than that of the internal arcs,said deformable assembly is constituted by a lamination of at least two transverse sheets of spring steel,said deformable assembly is constituted by multiple disjointed elastic elements, so as to form a pivot connection articulated in rotation with respect to said external drive means, and a pivot connection articulated in rotation with respect to said hub, and in particular said multiple elastic elements have a bent shape with two longitudinal arms,said deformable assembly is constituted by N disjointed elastic elements deformable in flexion, said mechatronic module comprising a part secured to said external drive means, having N housings for embedding the end of the elastic elements, and a crenellated crown, secured to the hub,having N convex profiles bearing on the surface of said deformable elastic elements opposite said embedding, said deformable assembly has a maximum angle of deformation obtained by the abutment of two complementary means, one being integral with the external drive means and the other being integral with the hub and in particular: the complementary means making it possible to ensure the abutment are in the form of a second notched crown integral with the hub and the teeth of which are interdigitated with teeth of an insert integral with the external drive means and alternatively, said deformable assembly has a maximum angle of deformation obtained by the abutment of the surface of said N elastic elements, opposite the bearing surface of the notched crown, against the housings of the transverse partition. Detailed description of a non-limiting example of embodiment.,

[0009] The present invention will be better understood upon reading the following description, concerning a non-limiting example of embodiment illustrated by the appended drawings where:represents a first embodiment of a mechatronic electric assistance module in exploded perspective view,represents a detailed front view of the torque sensor according to the first embodiment,represents a perspective view of the motor housing with the torque take-up part shown in exploded view,represents a front view of the torque sensor according to a second embodiment,represents an exploded perspective view of the torque sensor according to the second embodiment,represents a front view of the torque sensor according to a third embodiment of the torque sensor,represents a schematic view of the assembly deformable at rest according to a third embodiment,represents a schematic view of the deformable assembly during deformation according to the third embodiment., General principle

[0010] The invention proposes a very compact mechatronic electric assistance module (1) integrating both the electric motor (10) and the torque sensor necessary for measuring the force supplied by the user and making it possible to generate a control law for the electric motor to assist pedaling. The torque sensor is thus interposed between a torque input supplied by the user, in the form of a hub (200) and an output mechanically connected to the wheel, in the form of a flange (130).

[0011] A configuration allowing both very good integration and optimization of performance is to use an electric motor (10) called an external rotor (11), allowing to clear an internal cylindrical space to house the torque sensor. The rotor is integral with an external drive means (100) to transmit the generated torque to the wheel of the vehicle. The stator (not visible in the figures), being housed within the rotor, is fixed to the chassis and has a central cylindrical recess allowing to accommodate the hub (200), constituting the torque input connected to the pedal assembly, on which the torque sensor is partly fixed. The torque applied to the hub (200) by the user is also transmitted to the external drive means (100) for driving the wheels using a flange (130).

[0012] The torque sensor technology used incorporates a position sensor (400) which measures a differential displacement between two components mechanically connected by a calibrated deformable assembly (300), this type of sensor being known in particular from international patent application WO2006008425A1. The hub (200) is thus connected to the external drive means (100) via this deformable assembly (300) and the position sensor (400) measures the differential displacement between the hub (200) and the external drive means (100).

[0013] It should be noted that this application requires precise torque measurement; in fact, to generate maximum comfort for the user, the mechatronic electric assistance module must be able to precisely compensate for the force generated by the user and be very responsive, which implies being able to measure fairly low torques. Thus, the elasticity of the deformable assembly (300) must be large enough to generate measurable displacements when these low torques are applied. This large deformation capacity must be controlled to avoid reaching the plasticity zone of the deformable assembly (300), leading to irreversible deformation of the latter and therefore to a loss of sensor precision, or even to a breakage of the mechanical connection between the hub and the wheel.

[0014] The invention therefore provides for limiting the deformation range of the deformable assembly (300) and adding a mechanical stop to ensure the transmission of mechanical forces between the hub (200) and the external drive means (100) as soon as the torque applied at the input is located above a threshold value.

[0015] One of the major challenges is thus located at the level of the production of the deformable assembly (300) in a very reduced size. Indeed, to obtain a sufficient elastic deformation range, the material used which must have a high rigidity to deform elastically, must have a great length. Usually, these torque sensor technologies use long torsion shafts which is unfavorable to their integration in an environment highly constrained in the axial direction. The invention therefore provides a deformable assembly (300) whose deformations are obtained in a radial plane, also called transverse plane.

[0016] For this purpose, the external drive means (100) has a flange (130) provided with a housing (150) whose depth is less than a third of the axial size of said external drive means (100) and extending radially over a dimension similar to that of the stator. Said housing makes it possible to integrate the deformable assembly (300) in the desired size. The bottom of the housing (150) is delimited by a transverse partition (160) perforated by a passage (165) to allow the insertion of the hub (200) or a fixed guide axis.

[0017] The housing is further closed by a cover (120) with preferential cooperation of a peripheral seal (125).

[0018] The hub (200) is for example provided with a sleeve (201) passing through the external drive means (100) and allowing guidance with the passage (165) by means of a plain bearing (190), or can alternatively be coupled to a flange provided with multiple pins passing through slots in the transverse partition to transmit the torque to the support part of the multipolar ring magnet. The sleeve is terminated by an axial protrusion (202) providing support for the multipolar ring magnet (430) of the position sensor (400).

[0019] The hub (200) is the element that receives the torque exerted by the user via the crankset, but it is not the one that is directly driven by the motor. The motor drives another component, the external drive means (100), which is responsible for transmitting the movement to the bicycle wheel. The hub (200) serves as the point of application of the user's torque (via the crankset) and is used to capture the forces applied by the user, which are then measured for electric assistance.

[0020] The electric assist motor is not directly connected to the hub. The motor is connected to the external drive means (100), which is the driven part for rotating the wheel.

[0021] The hub (200) is used to sense the force applied by the user and transmit this force to the position sensor via a deformable assembly while the motor is configured to directly transmit the torque to the wheel without interposition of the deformable element.

[0022] The hub (200), being a part rotating synchronously with the wheel, has a tubular geometry to accommodate a fixed axle (not shown), that is to say integral with the frame of the pedal vehicle, on which it is guided in rotation by means of bearings.

[0023] In order to obtain the measurement of the torque supplied by the user, the position sensor (400) is provided with two toothed collectors (410, 420) made of ferromagnetic material. The teeth of the collectors (410, 420) extend in the axial direction opposite the multipolar ring magnet (430), the collectors being interdigitated. The number of teeth of the collectors (410, 420) is equal to the number of pairs of poles of the multipolar ring magnet (430) and the looping of the flux from a north pole of the magnet to a south pole is favored by its passage through the collectors (410, 420). The collectors (410, 420) are fixed to the hub (200) while the multi-pole ring magnet (430) is fixed to the external drive means (100) (or vice versa) and can therefore exhibit relative movement with respect to the collectors (410, 420) by deformation of the deformable assembly (300) when a torque is applied.The flux passing through the collectors (410, 420) is thus linked to the phase shift, between the teeth of the latter and the poles of the multipolar ring magnet (430), by a bijective law which is sought to be as linear as possible to maximize the precision of the sensor.

[0024] It may also be noted that the sensor technology used according to the invention is intrinsically limited in angular travel, a mechanical stop ensuring the transmission of mechanical forces between the hub (200) and the external drive means (100), as soon as the torque applied at the input is located above a threshold value, makes it possible, in addition to protecting the deformable assembly, to avoid deterioration of the position sensor (400).

[0025] The general principle will be illustrated through different examples of implementation and in particular detailed with regard to the deformable assembly (300) of the position sensor (400). First example of realization

[0026] Figures 1 to 3 illustrate a first embodiment of a torque sensor according to the invention.

[0027] In particular, this embodiment has a deformable assembly (300) in the form of a radially undulating flat crown, similar to a flower, having 9 inner arcs (331) and 9 outer arcs (332) distributed with a regular angular distribution and connected by 18 portions (330), each of the inner arcs (331) being connected to two outer arcs (332) and vice versa.

[0028] With reference to the center of the corrugated crown, the outer arcs (332) have a concave orientation while the inner arcs (331) have a convex orientation, each portion (330) connecting them having an inflection point (333) at the level of the neutral fiber of the deformable assembly.

[0029] The deformable assembly (300) is mechanically coupled to the hub via three connection points (311, 312, 313) in the form of radial protuberances each extending an internal arc (331) and cooperating with notches (241) of a crenellated crown (240) of the hub (200).

[0030] The connecting points (311, 312, 313) are regularly distributed and therefore have an angle of 120° between them, they thus extend an interior arc (331) out of three.

[0031] In order to ensure the transmission of torque to the external drive means (100), the deformable assembly (300) comprises a second set of connection points (321, 322, 323) in the form of holes, each made in an external arc (332), in which pins (121, 122, 123) are inserted, embedded in a transverse partition (160) of the external drive means (100). The connection points (321, 322, 323) located in external arcs (332) also have a regular distribution and are angularly equidistant with respect to the connection points (311, 312, 313) of the internal arcs (331).

[0032] The undulating path connecting each of the connection points (311, 312, 313) of the inner arcs (331) to one of the connection points (321, 322, 323) of one of the nearest outer arcs (332) is made through a succession of inner arcs (331) and outer arcs (332) connected by portions (330) so as to constitute an elastic element (310) deformable in bending, like a beam, the neutral fiber (320) of one of which is symbolically represented in dotted lines.

[0033] As illustrated, the deformable assembly (300) is made up of 6 identical deformable elastic elements (310) distributing the forces to be transmitted between the hub (200) and the external drive means (100).

[0034] As illustrated, each elastic element (310) extends in an angular sector such as that delimited by dashes.

[0035] The succession of internal arcs and external arcs constituting an elastic element (310), makes it possible to lengthen the path between its ends and gives it better power of deformation in bending in the radial plane.

[0036] The connection points (321, 322, 323) of the outer arcs (332) have a degree of freedom in rotation, around the axial direction, so as to limit the local forces at the connections and therefore to avoid premature wear of the deformable element (300). The position of said connection points (321, 322, 323) is also chosen so as to minimize the angle of rotation and therefore the wear of the elements in contact. Similarly, the cooperation between the notches (241) and the protuberances of the deformable assembly (300), to produce the connection points (311, 312, 313), allows a degree of freedom in rotation via a rolling contact, the instantaneous center of rotation moving with the deformations.

[0037] The regular distribution of the connection points (311, 312, 313, 321, 322, 323) to the hub (200) and to the external drive means (100) makes it possible to symmetrize the forces and therefore to improve the service life of the device.

[0038] The distribution of the homogeneous bending stresses of an elastic element (310) is obtained by a continuous variation of its width (W) in the direction orthogonal to the neutral fiber (320). Indeed, as the internal stresses are intrinsically linked to the geometry of the part and to the locations of embedding, it is possible to play on the rigidity and therefore to distribute the forces by locally modifying said width (W). In particular, the width (W) of the elastic element (310) is increased as a function of the distance, , between the neutral fiber (320) and the line segment (340), according to a law , the straight line segment (340) connecting the connection point (311, 312, 313) to the hub (200) and the connection point (321, 322, 323) to the external drive means (100) located at the ends of the elastic element. Typically an ideal sizing rule gives , but the width can be adjusted to meet technical feasibility constraints, the interest being above all to increase the thickness in the areas very far from the segment (340), where the torques are the greatest. In particular, the width (W) is also increased in the perimeter close to the connection points (321, 322, 323) by means of external drive (100) so as to be compatible with a pin assembly with the latter. Indeed, this assembly requires the creation of a hole in the elastic element which weakens it and introduces local torque forces.

[0039] The increase in the width (W) of the elastic element (310) as a function of the distance from the straight line (340) is essential when the connection points (311, 312, 313, 321, 322, 323) have a degree of freedom in axial rotation, in fact the torques exerted along the elastic element are then greater than in the context of an embedded connection which concentrates the stresses around the connection points.

[0040] The deformable assembly (300) presented in 2 can be produced by a monolithic part cut by shearing, electroerosion, sawing, or any other process known to those skilled in the art. This part could also be obtained by additive manufacturing, or be made of a laminated sheet metal assembly that is easier to cut. Also, the deformable assembly (300) as presented in figures 1 and 2 has axial symmetry for each spoke passing through a connection point (311, 312, 313, 321, 322, 323), but in the case where a torque, between the hub (200) and the external drive means (100), is transmitted in only one direction, the elastic elements (310) work for some only in compression and for others only in tension, the shape of the elastic elements (310) could then be adapted to optimize its resilience to a unidirectional force.The connecting points (311, 312, 313, 321, 322, 323) could also be in the form of a stop transmitting forces only in one direction of rotation.

[0041] In order to avoid damage to the mechatronic electric assistance module (1) when an over-torque is applied, the device is provided with a stop. This stop is achieved by bringing a part of the hub (200) into contact with a part of the external drive means (100) without the intermediary of the deformable assembly (300), as soon as the deformation of the deformable assembly exceeds a determined angle. For this purpose, the hub has a second notched crown (280) whose teeth (281) are interdigitated with teeth (181) of an insert (180) secured to the external drive means. The width of the teeth (181, 281) is chosen so as to provide the desired angular movement to define the threshold torque from which the torque transmission takes place through the teeth (181, 281) rather than through the deformable assembly (300).

[0042] The insert (180), shown in exploded view in the, is in the form of a wafer, the periphery of which is crenellated with teeth (182), inserting into a housing (161) of the transverse partition (160), said housing (161) comprising complementary teeth (162) and being held in axial position by means of screws (186). The cooperation of the teeth (162, 182) makes it possible to maximize the torque transmission surface between the insert (180) and the transverse partition (160) so as to best distribute the forces on the latter. Indeed, the flange (130) being preferably made of aluminum, the transmission of the forces directly from the hub (200) which has a small diameter, does not make it possible to transmit the forces to the flange (130) without risking its work hardening and therefore the appearance of play deteriorating the operation of the system.One option is therefore to increase the diameter to which the forces of the flange (130) are taken in order to maximize the contact surface and therefore reduce the contact pressure, this can be done through an intermediate part, the insert (180) which is made of a much harder material such as steel. A possible alternative to do without the insert (180) would be to use a flange (130) made of steel, but the consequence of which is a negative impact on the weight of the device.

[0043] It also allows the exploded view to be seen of the plain bearing (190) for guiding between the hub (200) and the passage (165) of the flange (160). As the hub (200) and the flange (160) are only set in relative motion when a torque is applied, the speed of movement and the travel path are very limited, which allows the use of a plain bearing (190), which is very compact, to guide this movement satisfactorily rather than a rolling bearing.

[0044] It should be noted that Figures 1 to 3 show only the multipolar ring magnet (430) and the collectors (410, 420) of the position sensor (400), at least one magnetosensitive probe and its electronics (not shown), but whose different arrangements are known from the state of the art, is necessary to measure the variations in the magnetic flux passing through the collectors. This magnetosensitive probe has the advantage of being fixed relative to the chassis of the vehicle and therefore movable relative to the collectors (410, 420).

[0045] Second embodiment of the deformable assembly

[0046] Figures 4 and 5 show an alternative embodiment of the deformable assembly (300) and the angular travel limiting stop between the hub (200) and the external drive means (100). For this embodiment, the deformable assembly (300) is made up of multiple disjointed arcuate elastic elements (310), each of these elastic elements (310) being in the form of two rectilinear arms (336, 337) connected by an elbow (335).

[0047] The connection points (311, 312, 313) between each of the elastic elements (310) and the hub (200) are produced by means of pins (220) embedded in the hub taking transverse support on the teeth (281) of a notched crown (280). Said pins cooperate with a cylindrical notch of the end of the arm (336) so as to provide a degree of freedom in rotation of the connection.

[0048] Similarly, the connection points (321, 322, 323) between each of the elastic elements (310) and the external drive means (100) are also produced by means of pins (121, 122, 123) embedded in the transverse partition (160). Said pins cooperate with a cylindrical notch of the end of the arm (337) so as to provide a degree of freedom in rotation of the connection. An axial protuberance (164) of the transverse partition (160) makes it possible to provide transverse support to the pin so as to improve the transmission of forces.

[0049] The elastic elements (310) are inserted with a slight elastic deformation between their respective pins, so that a force is always exerted between the elastic elements (310) and the pins in the rest position of the device, so as to ensure that the elastic elements (310) are held in position. When a torque is applied, the elastic elements (310) deform in bending at the elbow, following a compressive force exerted at the two ends (336, 337). An alternative or tensile forces exerted at the ends is nevertheless entirely conceivable for those skilled in the art, the connections at the ends nevertheless having to be slightly modified to accept this type of stress while maintaining the degree of freedom in rotation.

[0050] In order to ensure the stop function in the event of over-torque, another series of teeth (282) is provided at the hub (200), these teeth coming into abutment against inserts (180) taking the form of pins embedded in the transverse partition (160), as soon as a calibrated angular deformation is reached.

[0051] The inserts (180) bear transversely on axial protrusions (163) of the transverse partition (160) so as to improve the force-recovery surface and to avoid plastic deformations of the transverse partition (160).

[0052] The shape of the elastic elements (310) presented in 5 is in no way limiting of the invention and the person skilled in the art could envisage all sorts of alternatives making it possible to provide an elastic angular approximation of its ends. It would thus be possible to improve the flexion, in particular by continuously arched elastic elements, or even to promote compression thanks to elastic elements having a multitude of cusp points to form a zigzag structure.

[0053] Third embodiment of the deformable assembly

[0054] Figures 6 and 7 and 8 show a second alternative embodiment of the deformable assembly (300). This embodiment differs from the previous embodiments in that the deformable assembly (300) also performs the function of a stop. Indeed, for this embodiment, the elastic elements (310) are in the form of a beam and are inserted transversely into housings (161) of the transverse partition (160), these housings are open in the direction of the hub and are of a dimension close to that of the elastic elements (310) in the other directions. The elastic elements (310) are embedded by one of their ends (319) in the housings (161) by wedging between the housing (161) and a pin (121, 122, 123) so as to produce the connection points (321, 322, 323) with the external drive means (100).This embedding is ensured by taking into account manufacturing dispersions, by the use of a slightly oblique end (319) flank systematically coming to bear against the pin (121, 122, 123) thanks to a constraint ensured by a spring (350) inserted between the other end (318) and a wall of the housing (161). Of course, the connecting means described is only for illustration purposes and the person skilled in the art would be able to propose a set of alternatives making it possible to obtain the effect of embedding a beam.

[0055] The mechanical connection with the hub (200) is obtained at the other end (318) of the elastic elements (310) by pressing a toothing (282) against a flank of said end (318) to generate the connection points (311, 312, 313). The teeth (282) have a slightly convex profile to ensure a point contact (283) with the elastic elements (310), allowing a degree of freedom in rotation. These teeth (282) do not aim for a meshing effect, but are bearing surfaces provided with a cam profile acting in sliding and / or rolling contact with the bending part on the side opposite its embedding.

[0056] As more visible in Figures 7 and 8, which represent an exaggerated schematization of the connection points (311, 312, 313, 321, 322, 323), respectively in the rest state and when the elastic element (310) is deformed. The point contact (283), located at a distance of the end (318), moves, along the profile of the end of the teeth (283) of the elastic element (310), depending on the deformation of the deformable assembly (300) giving rise to a rolling contact point.

[0057] In order to avoid excessive deformation of the deformable assembly (300) making this deformation irreversible, the cutting of the housings (161) in the transverse partition has, along the external flank of the elastic elements (310), a slightly convex profile leading to the existence of a clearance between the elastic elements (310) and the wall of the housings (161) at the end (319) of said elastic elements (310) and located at the connection points (311, 312, 313) with the hub (200). When a torque is applied, the elastic elements (310) deform by tangential bending, tending to absorb the clearance between the side wall of the elastic element (310) and the transverse partition (160). The disappearance of this clearance occurs with the progressive displacement of the contact point (166), located at a distance from the end (319) of the elastic element (310), this distance being zero in the rest state, when the applied torque is zero, and increases relatively quickly as the elastic element (310) deforms, as illustrated in.

[0058] Thus, if too strong a torque is applied, this only leads to the entire flank of the elastic element (310) coming into contact with the flank of the housing (161), no longer allowing deformation of the elastic element in bending.

[0059] The bringing together of the contact points (166, 283) as a function of the applied torque leads to a progressive increase in the stiffness of the elastic element (310). This effect is particularly advantageous for improving the sensitivity of the device. When a low torque is applied, the stiffness is low and the deformations are large, which leads to maximum sensitivity of the sensor where the variations are most critical for the user's feeling. At high torque, the accuracy of the torque measurement is less constrained and the increase in stiffness makes it possible to limit the associated displacements. By this technique, the angular range attributed to low torques is favored, which increases the accuracy.

Claims

Mechatronic electrical assistance module (1) comprising an electric motor (10) formed by a rotor (11) and a stator having a plurality of wound teeth as well as a differential position sensor (400) interposed between two mechanical assemblies constituted and providing a signal representative of the torque exerted between these mechanical assemblies, said mechanical assemblies being a drive means (100) and a hub (200), one of the mechanical assemblies being integral with said rotor (11), characterized in that said position sensor (400) is associated with a deformable assembly (300) in the transverse plane, linked to said hub (200) at 2 to 8 connection points (321, 322, 323), and to the external drive means (100) by at least 2 connection points (311, 312, 313). Mechatronic electrical assistance module (1) according to claim 1 characterized in that at least part of said connection points (311, 312, 313, 321, 322, 323) has a degree of freedom in axial rotation. Mechatronic electrical assistance module (1) according to claim 1 characterized in that said deformable assembly (300) is deformable in flexion. Mechatronic electrical assistance module (1) according to claim 1 characterized in that said deformable assembly (300) is constituted by a radially undulating crown having a plurality of portions (330) connecting an outer arc (332) to an inner arc (331) each having an inflection point (333). Mechatronic electrical assistance module (1) according to the preceding claim, characterized in that a part of said external arcs (332) is free relative to said external drive means (100). Mechatronic electrical assistance module (1) according to the preceding claim, characterized in that the connections with said external drive means (100) are made by connection points (321, 322, 323) with a degree of freedom in axial rotation. Mechatronic electrical assistance module (1) according to the preceding claim, characterized in that said hub (200) is connected to said internal arcs (331) by connection points (311, 312, 313) with a degree of freedom in axial rotation. Mechatronic electrical assistance module (1) according to claim 4 characterized in that said external arcs (332) free relative to said external drive means (100) have a width (W) greater than that of the internal arcs (331). Mechatronic electrical assistance module (1) according to claim 1 characterized in that said deformable assembly (300) is constituted by a lamination of at least two transverse sheets of spring steel. Mechatronic electrical assistance module according to claim 1 characterized in that said deformable assembly (300) is constituted by multiple elastic elements (310) which are disjointed, so as to form a pivot connection articulated in rotation relative to said external drive means, and a pivot connection articulated in rotation relative to said hub. Mechatronic electrical assistance module according to the preceding claim, characterized in that said multiple elastic elements (310) have a bent shape (335), with two longitudinal arms (336, 337). Mechatronic electrical assistance module according to claim 1 characterized in that said deformable assembly (300) is made up of N elastic elements (310) deformable in flexion which are disjoint, said mechatronic module comprising a part secured to said external drive means (100), having N housings (161) for embedding the end of the elastic elements (310), and a crenellated crown (280), secured to the hub, having N convex profiles bearing on the surface of said deformable elastic elements (310) opposite said embedding. Mechatronic electrical assistance module according to claim 1 characterized in that said deformable assembly (300) has a maximum angle of deformation obtained by the abutment of two complementary means, one being integral with the external drive means (100) and the other being integral with the hub (200). Mechatronic electrical assistance module according to the preceding claim, characterized in that the additional means for ensuring the stop are in the form of a second crenellated crown (280) secured to the hub and whose teeth (281) are interdigitated with teeth (181) of an insert (180) secured to the external drive means (100). Mechatronic electrical assistance module according to claim 10 characterized in that said deformable assembly (300) has a maximum angle of deformation obtained by the abutment of the surface of said N elastic elements (310), opposite the bearing surface of the crenellated crown (280), against the housings (161) of the transverse partition (160).

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