SYSTEM FOR DETERMINING A TORQUE BETWEEN TWO ROTATING PARTS

Description

[0001] The invention relates to a system for determining a torque applied between two members rotating around an axis of rotation, as well as a module for transmitting a torque between a rotating shaft and a second member which comprises such a system.

[0002] The invention applies in particular to the determination of a torque applied between two members integrated in a transmission of a motor torque to a vehicle, for example between the electric motor or the pedal assembly and the mechanical transmission of an electrically assisted bicycle.

[0003] To do this, it is known to use a test body having an inner ring integral in rotation with means for coupling said test body to a first of the members, and an outer ring extending around the inner ring while having means for coupling said test body to the second of the members, said rings being connected concentrically around the axis of rotation by a deformable structure which is arranged to transmit the torque between the members while allowing angular movement between said rings as a function of the torque applied between the members.

[0004] Such a test body can be instrumented with two encoders by equipping each of the rings with a ring carrying a magnetic track, respectively inner and outer, which is capable of emitting a periodic signal representative of the rotational movement of the corresponding ring. In particular, each of the tracks has a succession of pairs of North and South poles to form a multipolar magnetic track delivering a pseudo-sinusoidal magnetic signal.

[0005] The determination system then comprises a torque determination device, which may in particular comprise a support carrying two sensors, respectively internal and external, each comprising a pattern of sensitive elements arranged at a reading distance from the internal or external track to deliver a signal representative of the angular position of the corresponding encoder.

[0006] Documents FR-2 816 051, FR-2 821 931, FR-2 862 382, ​​EP1408603 A1 and FR 3020434 A1 describe the use of a device for comparing such signals which is capable of determining an angular difference between the rings, and therefore the torque applied in that it induces said angle by twisting the deformable structure.

[0007] In known systems, the problem arises of adjusting the air gap, i.e. the reading distance between the encoder tracks and the sensors, which must be carried out in a precise, stable and equivalent manner for both sensors, so as not to distort the determination of the torque. In particular, such an adjustment must be able to be adjusted during the lifetime of the transmission module, especially in the event of a change of the test body.

[0008] The air gap adjustment means must also have minimal axial bulk, in particular by being contained in a casing, so as not to interfere with the exterior of said casing.

[0009] The invention aims to improve the prior art by proposing in particular a system for determining a torque which is arranged to resolve the problems of adjusting the air gap noted above.

[0010] To this end, according to a first aspect, the invention proposes a system for determining a torque applied between two rotating members around an axis of rotation, said system comprising: a test body having an inner ring integral in rotation with means for coupling said test body to a first of the members, and an outer ring extending around the inner ring while having means for coupling said test body to the second of the members, said rings being connected concentrically around the axis by a deformable structure which is arranged to transmit the torque between the members while allowing an angular movement between said rings according to the torque applied between said members; two encoders respectively inner integral in rotation with the inner ring and outer integral in rotation with the outer ring, each of said encoders carrying a track capable of emitting a periodic signal representative of the rotational movement of the corresponding ring;a torque determination device comprising a support carrying an inner sensor and an outer sensor, each of the sensors comprising a pattern of sensitive elements arranged at a reading distance from the inner or outer track to deliver a signal representative of the angular position of the corresponding encoder, said device comprising means for comparing the signals delivered by each of the sensors to determine an angular difference between the rings which is a function of the torque applied;a casing in which the test body, the encoders and the determination device are housed, said casing having an external wall having a cavity forming a housing in which a plate is fixed, said plate being associated with the support by means of an adjustment screw which is arranged so that the rotation of said screw induces a translation of said support relative to the test body to allow the adjustment of the reading distance of the tracks by the respective sensors.;

[0011] According to a second aspect, the invention proposes a module for transmitting a torque between a rotating shaft and a second member, said module comprising such a determination system, in which the inner ring has an association bore around the rotating shaft, said module comprising a bearing for rotating said shaft through an orifice in the casing.

[0012] Other objects and advantages of the invention will appear in the following description, made with reference to the appended figures, in which: [ Fig.1 ] is a partial perspective representation of the crankset of an electrically assisted bicycle equipped with a torque determination system according to the invention, the figure 1a being an exploded perspective view of the system of the figure 1 showing more particularly the assembly of the test body; [ Fig.2 ] is an exploded perspective view of the crankset of the figure 1 , [ Fig.2a ] being a partial cross-section of said crankcase centered on the inside of the crankcase, [ Fig.2b ] being a partial section, along a direction D perpendicular to a radial direction, of said determining device; [ Fig.3a ], [ Fig.4a ], [ Fig.3b ] And [ Fig.4b ] are views analogous to respectively the figure 2a and the figure 2b , in which the reading distance is set with a respectively minimal dimension ( figures 3a, 3b ) and maximum ( figure 4a, 4b ).

[0013] In relation to these figures, a system for determining a torque applied between two members 1, 2 rotating around an axis of rotation R is described below, as well as a module for transmitting a torque between a rotating shaft 1a and a second member 2, 2a comprising such a system.

[0014] In this description, the terms of positioning in space are taken with reference to the axis R of rotation. In particular, the terms "interior" and "exterior" relate to an arrangement respectively close to and at a distance from this axis R, and the terms "axial" and "radial" relate to an arrangement respectively along this axis R and moving away from or approaching it.

[0015] In particular, the system allows the determination of a torque applied between two members 1, 2 integrated in a transmission of a motor torque to a vehicle, for example at the level of the pedal assembly of an electrically assisted bicycle.

[0016] There figure 1 represents a crankset of an electrically assisted bicycle comprising a crank 3 equipped with a pedal 4, said crank being mounted on a shaft 1a driven in rotation along the axis R to form a member 1 for applying a pedaling torque M+ depending on the direction of pedaling.

[0017] The system comprises a test body which makes it possible to transmit the pedaling torque M+ to the other of the members 2, which, in the figures, is represented in the form of a sleeve 2a, for example a satellite carrier of an epicyclic train of a motorized gearbox, exerting a torque Mbv.

[0018] In this application, the pedaling force F at the end of the pedal 4 to be considered according to standard EN15194: 2017 is 1,500 N which, with a crank length 3 of 165 mm, generates a pedaling torque M+ of the order of 250 Nm. In particular, the torque to be transmitted by the test body is only in one direction of rotation (that represented by the arrow M+ in the figures), since the other direction corresponds to the freewheel of the bicycle.

[0019] The test body has an inner ring 5 integral in rotation with means for coupling said test body to the first member 1, as well as an outer ring 6 extending around the inner ring 5 while having means for coupling said test body to the second member 2.

[0020] In relation to the figures, the inner ring 5 has a bore 7 equipped with coupling means on the shaft, for example in the form of a thread or grooves.

[0021] With regard to the coupling to the other member 2, the figures represent an inner circumferential wall of the outer ring 6 which has at least one radial lobe 8 which is equipped with a means 9 for fixing said outer ring on the sleeve 2a. In particular, three lobes 8 at 120° are provided, each of them having a fixing orifice 9, in particular by a pin or by screwing into a complementary orifice of the sleeve 2a.

[0022] The rings 5, 6 are concentrically connected around the axis R by a deformable structure which is arranged to transmit the torque between the members 1, 2 while allowing angular movement between said members as a function of the torque applied between said members.

[0023] In particular, the torque resulting from the pedaling torques M+ on the inner ring 5 and the torque Mbv applied by the sleeve 2a on the outer ring 6 induces a torsion between the rings 5, 6, and therefore a relative angular displacement of said rings according to a torsion angle which is a function of said torque.

[0024] In the embodiment shown, the deformable structure comprises a set of branches 10 distributed angularly between the rings 5, 6. In particular, the branches 10 and the rings 5, 6 are formed in a single piece, in particular by stamping and / or by cutting a blank of metallic material.

[0025] The branches 10 are inclined in the opposite direction to the rotation, which generates a lever arm which, by stressing the branches 10 in traction, reduces the constraints in a very effective manner with the counterpart of an increase in stiffness.

[0026] In the figures, the test body comprises three branches 10 which are separated by a sector without a branch. In particular, the sectors without a branch extend over an angle which is greater than 60°, the lobes 8 each extending into a sector without a branch.

[0027] To facilitate the coupling of the inner ring 5 to the first member 1, a nut 11 for coupling the test body with the rotating shaft 1a is attached by being fixed in the bore 7, in particular by being fitted into said bore.

[0028] This embodiment allows simplified manufacturing of the rings 5, 6 and the deformable structure, in particular by stamping, and to machine the coupling nut 11 separately before its fixing. In addition to the economic benefit of forming the body by stamping, the inner ring 5 can be produced with a dimension just sufficient for fixing the nut 11, in order to benefit from a compact test body while maximizing the length of the deformable branches 10.

[0029] In particular, the nut 11 may have a bore 11a allowing coupling of the test body to a shaft 1a of the first member 1, said bore being equipped with a thread or coupling grooves. In the figures, the nut 11 is mounted in axial abutment on a radial shoulder 12 formed for this purpose on the rotating shaft 1a, and is axially immobilized between said radial shoulder and an elastic washer 13 of the “circlip” type mounted in an annular groove 14 formed at the periphery on said rotating shaft.

[0030] Advantageously, the bore 7 of the inner ring 5 may have geometric means, for example grooves, the outer periphery of the nut 11 having complementary geometric means, for example complementary grooves, to make the rotational retention of said nut in said bore more reliable.

[0031] The system comprises a device for determining the angle between the rings 5, 6 which, in particular taking into account the stiffness of the deformable structure, is a function of the torque applied.

[0032] To do this, the system comprises two encoders, including an inner encoder 15 integral in rotation with the inner ring 5 and an outer encoder 16 integral in rotation with the outer ring 6.

[0033] In particular, each encoder 15, 16 comprises a ring fixed to a ring 5, 6 respectively and carrying a magnetic track, respectively inner 15a and outer 16a, which is capable of emitting a periodic signal representative of the rotational movement of the corresponding ring 5, 6.

[0034] In the embodiment shown, each of the rings is carried by an inner 15b and outer 16b frame respectively, the inner ring 5 - outer 6 respectively - having means for fixing the inner 15b - outer 16b - frame respectively on it.

[0035] In particular, each of the rings 5, 6 has orifices 5a, 6a for fixing the frames 15b, 16b, in particular by screwing or riveting. In relation to the figure 1a , the inner ring 5 has an outer circumferential wall provided with three radial lobes 17, each ring 5, 6 having three fixing orifices 5a, 6a arranged at 120° to each other and being formed on each of its lobes 8, 17.

[0036] According to one embodiment, a succession of pairs of North and South poles is magnetized on a ring of the encoders 15, 16 respectively to form a multipolar magnetic track 15a, 16a capable of emitting a magnetic signal of pseudo-sinusoidal shape.

[0037] The rings of the encoders 15, 16 may each comprise an annular matrix, for example made from a plastic or elastomer material, in which magnetic particles are dispersed, in particular particles of ferrite or rare earths such as NdFeB, said particles being magnetized to form the magnetic tracks 15a, 16a.

[0038] The system further comprises a torque determining device which comprises: a support 18 carrying an inner sensor 19 and an outer sensor 20, each of said sensors comprising a pattern of sensitive elements arranged at a reading distance from the inner track 15a - respectively from the outer track 16a - to deliver a signal representative of the angular position of the corresponding encoder 15, 16; means for comparing the signals delivered by each of the sensors 19, 20 to determine an angular difference between the rings 5, 6 which is a function of the torque applied.

[0039] Each sensor 19, 20 may comprise a pattern of at least two sensitive elements, in particular a plurality of aligned sensitive elements, as described in documents FR-2 792 403, EP-2 602 593 and EP-2 602 594.

[0040] The sensitive elements may be based on a magnetoresistive material whose resistance varies according to the magnetic signal of track 15a, 16a to be detected, for example of the AMR, TMR or GMR type, or a Hall effect probe.

[0041] According to one embodiment, the angular position can be determined incrementally by means of the signal emitted by a magnetic track 15a, 16a. In particular, the sensors 19, 20 can be arranged to deliver incremental square signals in quadrature, the comparison means comprising counting means indicating the angular position of each of the encoders 15, 16 and subtraction means making it possible to calculate the difference between said angular positions, in particular as described in documents FR-2 816 051, FR-2 821 931 and FR-2 862 382.

[0042] According to one embodiment, the angular position can be determined absolutely, that is to say relative to a reference position, by providing a secondary magnetic track or specific coding on the ring of an encoder 15, 16.

[0043] In relation to the figures, the determination system further comprises a casing 21 in which the test body, the encoders 15, 16 and the determination device are housed.

[0044] In particular, the casing 21 comprises an external wall 22 provided with an orifice 23 through which the rotating shaft 1a is mounted in rotation by means of a rolling bearing 24, said rotating shaft having an end piece 25 projecting from said external wall which is equipped with the crank 3 for applying a pedaling torque M+, which is arranged opposite said external wall.

[0045] The external wall 22 has a cavity 26 forming a housing 27 in which a plate 28 is fixed, said plate being associated with the support 18 by means of an adjustment screw 29 which is arranged so that the rotation of said screw induces a translation of said support relative to the proof body, so as to allow adjustment of the reading distance E of the tracks 15a, 16a by the respective sensors 19, 20.

[0046] In the figures, the external wall 22 of the casing 21 is surrounded by a skirt 30 inside which the adjustment screw 29 is arranged, in particular so as to be entirely contained inside said casing.

[0047] Advantageously, the entire torque determination device is contained between the external wall 22 and the reading face of the tracks 15a and 16a. Thus, the system for adjusting the distance E is integrated into a volume that is restricted in height while ensuring that the external wall 22 of the casing 21 remains completely clear without any protruding parts (which means that all mechanical movements must be contained within this available envelope) and allowing easy sealing to be ensured by means of an access hatch 35.

[0048] The cavity 26 has an opening 31 which opens into the interior of the casing 21, having two rims 32 with which the plate 28 is associated by covering said opening. In the embodiment shown, the opening 31 has a rectangular geometry similar to that of the plate 28. The rims 32 are formed on the short sides of the opening 31, said rims being opposite in a direction D which is perpendicular to the radial direction defining the cutting plane of the figures 2b, 3b And 4b .

[0049] The plate 28 is fixed in its housing 27 by means of two screws 33 which are each associated with a respective rim 32. To limit the axial size of the fixing screws 33 in the housing 27, the plate 28 comprises two end counterbores 28a on each of which the actuating head 33a of a respective screw 33 is arranged set back from the upper surface 28b of said plate.

[0050] Furthermore, each rim 32 has a boss 34 formed in relief from the internal wall 37 of the casing 21, so as to form material to make the screwing of said plate more reliable while limiting the axial size of said screwing in the housing 27. This arrangement also makes it possible to prevent the screws 33 from protruding inside the casing 21, and thus to avoid their interference with the sensors 19, 20 and / or the encoders 15, 16.

[0051] According to one embodiment, the edges 32 and the short sides of the plate 28 can be provided with a keying structure to indicate the direction and mounting position to be respected to fix said plate in its housing 27.

[0052] Advantageously, the adjustment screw 29 has an actuating head 29a which is arranged in the housing 27 of the cavity 26 without protruding axially beyond the external wall 22, so as not to interfere with the crank 3 of the pedal set, and thus not to hinder the actuation of said pedal set.

[0053] To do this, the plate 28 comprises a central counterbore 28c on which the actuating head 29a is arranged set back from the upper surface 28b of said plate. In particular, in the embodiment shown, the adjusting screw 29 has a larger diameter than the fixing screws 33 and is arranged so that its actuating head 29a protrudes slightly from the upper surface 28b of the plate 28, as opposed to the heads 33a of said fixing screws, which are both arranged in the extension of said upper surface. Thus, the adjusting screw 29 is more easily identifiable by an operator, which makes it possible to avoid confusion between said adjusting screw and the fixing screws 33.

[0054] Advantageously, the cavity 26 is equipped with a closing hatch 35, in particular a sealed one, which is arranged in the extension of the external wall 22. The head 29a is arranged under the hatch 35, in particular in that the adjustment screw 29 is arranged so that its actuating head 29a is set back from the contact surface between the hatch 35 and the housing 27, a functional clearance having to remain between the screw 29 and the hatch 35.

[0055] Thus, the determination device, and more generally the interior of the casing 21, is protected from the external environment when the hatch 35 is present, so as to prevent the entry through the cavity 26 of external pollutants such as water, dust and / or mud. Furthermore, the absence of axial protuberance at the level of the hatch 35 makes it possible to avoid its interference with the crank 3 of the pedal assembly.

[0056] In particular, the determination device, like all of the elements internal to the casing 21, can be constantly immersed in an oil bath, the trapdoor ensuring that the oil does not escape from the casing 21, which would lead to rapid deterioration of the mechanical transmission system and potential breakage of the drive elements.

[0057] The adjustment screw 29 is arranged to rotate through the plate 28 while being immobilized in translation, and is mounted in a helical connection in the support 18 to allow translational movement of said support by rotation of said adjustment screw.

[0058] To do this, the adjustment screw 29 is fixed to the plate 28 by means of a metal stop ring 36, for example of the “truarc” type, which is arranged in a groove 38 provided for this purpose under the actuating head 29a of said adjustment screw, and which comes into axial abutment under the lower surface 28d of said plate.

[0059] In particular, the stop ring 36 may be arranged to limit any play along the axis of the screw 29 of said ring in the groove 38, for example by producing a curving by local deformation of said ring. Thus, the ring 36 may fulfill a spring function, in order to limit the axial play of said ring in the groove 38, and thus to avoid the use of an additional spring washer.

[0060] The support 18 comprises a plate 39 on which is associated a card 40 of a printed circuit carrying the sensors 19, 20, the adjustment screw 29 being associated with said plate. The support plate 39 linked to the electronic card 40 helps to give rigidity to this assembly. In particular, the card 40 is associated with the plate 39 by means of two fixing screws 44.

[0061] Advantageously, the installation of the two screws 44 for fixing the card 40 on the plate 39 is provided so that the heads of said screws fall between the two encoders 15, 16, which will make it possible to avoid any risk of collision when said encoders come into contact with the sensors 19, 20 during the adjustment operation. In addition, the adjustment screw 29 is also included between the two encoders 15, 16.

[0062] The adjusting screw 29 is mounted in a tapped hole 41 formed in the plate 39 to allow translation of said plate by rotation of said adjusting screw, and the card 40 has an orifice 42 aligned with said tapped hole through which the end of the adjusting screw 29 passes.

[0063] As shown in the figures 2a , 3a And 4a , the sensors 19, 20 are spaced apart by a radial distance R c , and the adjustment screw 29 is associated with the support 18 in the middle of this distance R c . Thus, simultaneous adjustment of the reading distance E of the two sensors 19, 20 is possible by means of the screw 29, with good balancing between said adjustments.

[0064] The plate 28 is associated with the support 18 by means of at least one pin 43 which is arranged to immobilize in relative rotation said support and said plate. In the figures, the plate 28 is associated with the support 18 by means of two pins 43 which are arranged on either side of the adjustment screw 29 while being aligned in the direction D presented previously.

[0065] Each pin 43 is fixed to one of the support 18 and the plate 28, and is slidably mounted relative to the other of said support and said plate.

[0066] In the embodiment shown, each pin 43 is fixed in the support 18 and is slidably mounted in a respective orifice 45 formed in the plate 28, so as to ensure translational guidance between the support 18 and said plate over a stroke of reduced size, but sufficient to absorb the dimensional variations of the components entering the dimension chain which may have an impact on the reading distance E of the sensors 19, 20.

[0067] The plate 28 further comprises at least one pressure screw 46 which is arranged to be able to be placed in contact with the support 18 when it is positioned at a desired reading distance E, in order to guarantee the immobilization of said support, and therefore of said reading distance.

[0068] In the embodiment shown, the system comprises two pressure screws 46 arranged on either side of the adjustment screw 29 while being aligned in the direction D.

[0069] Advantageously, the pins 43, the pressure screws 46 and the adjustment screw 29 are all aligned along the direction D, and in particular perpendicular to the reading axis of the sensors 19, 20, while being substantially equally distributed, each of the pressure screws 46 being arranged between the adjustment screw 29 and a pin 43. Thus, the risks of the card 40 carrying the sensors 19, 20 being skewed during adjustment of the screw 29 are limited, as well as during immobilization of the adjustment by tightening the pressure screws 46.

[0070] The device is arranged to allow adjustment of the common reading distance E between the encoders 15, 16 and sensors 19, 20 over a range of values ​​from E min to E max ranging from 0 to 2.4 mm. In particular, to obtain the desired adjustment, it is possible, starting from the contact position of the encoders 15, 16 / sensors 19, 20 shown in the figures 3a, 3b , corresponding to the minimum reading distance E min (zero): unscrew the adjustment screw 29 by a certain angle, for example by one turn, until the desired distance E is reached, then tighten the pressure screws 46 in contact with the support plate 18, 39, in order to maintain the adjustment of the distance E by stressing the thread of said adjustment screw in said support plate; or slightly tighten the pressure screws 46 to put them in contact with the support plate 18, 39, then loosen said pressure screws by a certain angle, for example by half a turn, to obtain a distance corresponding to the desired reading distance E, before tightening the adjustment screw 29 to ensure a counter-force for locking said plate in position at said desired reading distance. In particular, this solution does not cause any play to be taken up or the support 18 to be skewed.

[0071] The adjustment range of the common reading distance E between the encoders 15, 16 and sensors 19, 20 must allow any mechanical play to be maintained between the different moving elements making up the torque determination device, in particular: between the pins 43, the pressure screws 46 and the contact surface between the hatch 35 and the housing 27, while maintaining admissible engagement guide lengths of the elements; between the ring 36 and the plate 39 of the support 18; between the internal periphery of the opening 31 and the external periphery of the plate 39 of the support 18; between the bottom of the screw 29 and the encoders 15, 16.

Claims

1. A system for determining a torque applied between two rotating members (1, 2) about an axis of rotation (R), said system comprising: - a test body having an internal ring (5) secured in rotation to means for coupling said test body to a first one amongst the members (1), and an external ring (6) extending around the internal ring (5) while having means for coupling said test body to the second one amongst the members (2), said rings being concentrically linked around the axis (R) by a deformable structure which is arranged to transmit the torque between the members (1, 2) while enabling an angular displacement between said rings according to the torque applied between said members; - two encoders, respectively an internal one (15) secured in rotation to the internal ring (5) and an external one (16) secured in rotation to the external ring (6), each of said encoders carrying a track (15a, 16a) capable of emitting a periodic signal representative of the rotational displacement of the corresponding ring (5, 6); - a device for determining the torque comprising a support (18) carrying an internal sensor (19) and an external sensor (20), each of the sensors (19, 20) comprising a pattern of sensitive elements arranged at a reading distance (E) from the internal (15a) or external (16a) track to output a signal representative of the angular position of the corresponding encoder (15, 16), said device comprising means for comparing the signals outputted by each of the sensors (19, 20) to determine an angular offset between the rings (5, 6) which depends on the applied torque; - a casing (21) in which the test body, the encoders (15, 16) and the determination device are housed, said casing having an outer wall (22); said system being characterised in that the outer wall (22) has a cavity (26) forming a compartment (27) in which a subplate (28) is fastened, said subplate being associated with the support (18) by means of a setting screw (29) which is arranged so that the rotation of said screw induces a translation of said support relative to the test body to enable setting of the reading distance (E) of the tracks (15a, 16a) by the respective sensors (19, 20).

2. The torque determination system according to claim 1, characterised in that the setting screw (29) is rotatably arranged throughout the subplate (28) while being immobilised in translation, said screw being mounted in helical connection in the support (18).

3. The torque determination system according to one of claims 1 or 2, characterised in that the cavity (26) is equipped with a closure hatch (35), in particular sealed, said hatch being arranged in the continuation of the outer wall (22).

4. The torque determination system according to any one of claims 1 to 3, characterised in that the setting screw (29) has an actuating head (29a) which is arranged in the compartment (27) of the cavity (26) without protruding axially beyond the outer wall (22).

5. The torque determination system according to any one of claims 1 to 4, characterised in that the support (18) comprises a plate (39) on which a printed circuit board (40) is associated, the setting screw (29) being associated with said plate.

6. The torque determination system according to any one of claims 1 to 5, characterised in that the sensors (19, 20) are spaced apart by a radial distance (Rc), the setting screw (29) being associated with the support (18) at the middle of said distance.

7. The torque determination system according to any one of claims 1 to 6, characterised in that the subplate (28) is associated with the support (18) by means of at least one pin (43) which is arranged so as to immobilise the relative rotation of said support and said subplate.

8. The torque determination system according to claim 7, characterised in that the subplate (28) is associated with the support (18) by means of two pins (43) which are arranged on either side of the setting screw (29) while being aligned along a direction (D) which is perpendicular to a radial direction.

9. The torque determination system according to any one of claims 1 to 8, characterised in that the subplate (28) comprises at least one pressure screw (46) which is arranged so as to be able to bear on the support (18) when it is positioned at a given reading distance (E).

10. The torque determination system according to claim 9, characterised in that two pressing screws (46) are arranged on either side of the setting screw (29) while being aligned along a direction (D) which is perpendicular to a radial direction.

11. The torque determination system according to any one of claims 1 to 10, characterised in that the cavity (26) has an opening (31) having two flanges (32), the subplate (28) covering said opening while being associated with said flanges.

12. The torque determination system according to claim 11, characterised in that each of the flanges (32) has a boss (34) which is formed in relief on the inner wall (37) of the casing (21).

13. The torque determination system according to any one of claims 1 to 12, characterised in that the deformable structure comprises a set of branches (10) angularly distributed between the rings (5, 6).

14. A module for transmitting a torque between a rotating shaft (1a) and a second member (2, 2a), said module comprising a torque determination system according to any one of claims 1 to 13 wherein the internal ring (5) has a mating bore (7) around the rotating shaft (1a), said module comprising a bearing (24) for rotatably mounting said shaft throughout an orifice (23) of the casing (21).

15. The torque transmission module according to claim 14, characterised in that the shaft (1a) has an endpiece (25) projecting from the outer wall (22) of the casing (21), said endpiece being equipped with a crank (3) for applying a torque (M+) which is arranged opposite said outer wall.