Locking mechanism

Abstract

The invention relates to a locking mechanism comprising: a movable pawl (34) pivotally mounted between a locking position and a released position, the movable pawl comprising a cam surface; a thrust device (38) comprising a cam follower moving on the cam surface to move the movable pawl from the released position to the locking position; an actuating lever (3) moving the thrust device and comprising an outer periphery comprising a first notch and a second notch; a positioning member (2) engaging in the first notch in the locking position and in the second notch in the released position; the positioning member comprising an elastic device exerting an axial force on the outer periphery of the actuating lever. (Abstract Figure: 2)

Description

Title of the invention: Locking mechanism Technical field

[0001] The present invention relates to a locking mechanism for locking the rotation of a shaft of a transmission chain of a mobility device, such as a motor vehicle for example. Technological background

[0002] Locking mechanisms are used, for example, as a parking brake to secure a stationary motor vehicle. In such a case, they make it possible to lock a drive shaft of the motor vehicle in rotation. Such locking mechanisms are used in particular in motor vehicles with automatic transmission, in hybrid vehicles or in electric vehicles.

[0003] It is known, in particular from document US2018 / 0112774, locking mechanisms comprising a movable pawl equipped with a locking finger and pivotally mounted on a transmission casing between a released position and a locking position in which the locking finger is inserted into a locking recess integral in rotation with the transmission shaft to be locked. The locking mechanism further comprises a thrust device guided in translation on the transmission casing and comprising a cam follower which cooperates with a cam surface of the pawl so that a translational movement of the thrust device causes the pawl to pivot between the released position and the locking position.

[0004] An actuating lever is used to actuate the movement of the thrust device. The actuating lever is pivotally mounted about an actuating axis on the transmission housing and driven in rotation, directly or indirectly, by the rotor shaft of an electric motor.

[0005] Most often, the actuating lever is in the form of a flat part perpendicular to the actuating axis and which comprises on a cutout of its periphery an external periphery having a first and a second angular positioning notch. A positioning member fixed on the transmission casing comprises an elastic device, for example in the form of a flexible blade, pressing radially on the external periphery of the actuating lever. The flexible blade has a flat shape so as to easily obtain a targeted stiffness while having a simple and economical production process. The positioning member is configured to engage in the first angular positioning notch when the movable pawl is in the locked position, and in the second angular positioning notch when the movable pawl is in the released position.

[0006] The positioning member thus makes it possible to maintain the position of the locking mechanism in a stable and precise manner in the released position and / or in the locked position.

[0007] Such a structure of the locking mechanism poses several technical problems, firstly its assembly which must be simplified. Indeed, due to the flat shape of the flexible blade and its radial support on the actuating lever, the fixing of the positioning member must be done perpendicular to the actuating axis. The fixing of the actuating lever is carried out parallel to the actuating axis. The various components of the locking mechanism must therefore be fixed on the transmission casing along fixing axes which are not parallel to each other, which induces an assembly of these in several complex operations. In parallel with the improvement of the assembly, the locking mechanism must be simpler and more economical to produce, while retaining sufficient mechanical strength to withstand the mechanical stresses occurring during the stopping phases of the vehicle. Summary

[0008] In all that follows, ordinal numeral adjectives are used to differentiate characteristics. They do not define the position of a characteristic. Therefore, for example, a third characteristic of a product does not mean that the product has a first and / or a second characteristic.

[0009] An idea underlying the invention is a locking mechanism intended to lock the rotation of a shaft of a vehicle.

[0010] An idea underlying the invention is a blocking mechanism which makes it possible to solve one or more technical problems of the prior art, for example the aforementioned problems.

[0011] The invention relates to a locking mechanism capable of being mounted in a transmission casing of a vehicle to lock in rotation a shaft equipped with at least one locking recess, the locking mechanism comprising: • a movable pawl comprising a locking finger, the movable pawl being pivotally mounted about a pivot axis between a locking position in which the locking finger is engaged in the locking recess and a released position in which the locking finger is disengaged from said locking recess, the movable pawl comprising a cam surface; • a thrust device comprising a cam follower capable of moving on the cam surface in order to move the movable pawl from the released position to the locking position; • an actuating lever pivotally mounted about an actuating axis and configured to move the pushing device, the actuating lever comprising an external periphery comprising a first positioning notch angular positioning and a second angular positioning notch; and • a positioning member cooperating with the external periphery of the actuating lever, the positioning member comprising a bearing surface configured to engage in the first angular positioning notch when the movable pawl is in the locked position and in the second angular positioning notch when the movable pawl is in the released position; the positioning member further comprising an elastic device exerting a force, directly or indirectly, on the external periphery in a direction parallel to the actuation axis.

[0012] Thanks to the architecture according to the invention, the positioning member can be easily oriented so that its assembly is carried out in a direction parallel to the actuating axis. Consequently, the assembly of the actuating lever and the positioning member is carried out along parallel axes. They can therefore be mounted together during the same assembly operation.

[0013] According to another aspect of the invention, the invention relates to a locking mechanism capable of being mounted in a transmission casing of a vehicle to lock in rotation a shaft equipped with at least one locking recess, the locking mechanism comprising: • a movable pawl comprising a locking finger, the movable pawl being capable of being pivotally mounted about a pivot axis on the transmission casing between a locking position in which the locking finger is engaged in the locking recess and a released position in which the locking finger is disengaged from said locking recess, the movable pawl comprising a cam surface; • a thrust device comprising a cam follower capable of moving on the cam surface in order to move the movable pawl from the released position to the locking position; • an actuating lever being capable of being pivotally mounted about an actuating axis on the transmission casing and being configured to move the thrust device, the actuating lever comprising an external periphery comprising a first angular positioning notch and a second angular positioning notch; and • a positioning member cooperating with the external periphery of the actuating lever, the positioning member comprising a bearing surface configured to engage in the first angular positioning notch when the movable pawl is in the locking position and in the second angular positioning notch when the movable pawl is in the released position; the positioning member further comprising an elastic device exerting a force, directly or indirectly, on the external periphery in a direction parallel to the actuation axis.

[0014] For the purposes of this application: • “axially” means “parallel to the actuation axis”; • “radially” means “along an axis belonging to a plane orthogonal to the actuation axis and intersecting this actuation axis”; • “angularly” or “circumferentially” means “around the axis actuation”; • the terms "external" and "internal" are used to define the relative position of a component with respect to the axis of rotation for which it is concentric, a component close to said axis is thus qualified as internal as opposed to an external component located radially on the periphery; • two parts are said to be “fixed” or “rigidly secured” when they are permanently immobilized relative to each other, this immobilization being able to result from a fixing of the first part on the second part directly or by means of one or more intermediate parts.

[0015] According to an additional characteristic of the invention, the elastic device is a flexible blade which deforms elastically and axially when the positioning member moves around the external periphery of the actuating lever.

[0016] The flexible blade is a simple and economical solution which allows easy determination of a geometry compatible with a limited available space while ensuring sufficient stiffness and mechanical resistance to maintain the locking mechanism in position.

[0017] Advantageously, the flexible blade is flat or slightly bent, for example with a bending angle of less than 30°, in order to facilitate its manufacture and improve its mechanical strength by avoiding concentrations of mechanical stresses in the folds.

[0018] According to an additional characteristic of the invention, the positioning member comprises a rolling element arranged on the elastic device, the rolling element being configured to roll on the external periphery of the actuating lever.

[0019] The rolling element makes it possible to improve the durability of the locking mechanism by limiting wear and relative friction between the external periphery of the actuating lever and the flexible blade.

[0020] Advantageously, the rolling element may be a cylindrical roller. A complementary shape may then be provided on the end of the flexible blade in order to constitute a pivot connection between the cylindrical roller and the flexible blade.

[0021] According to an additional characteristic of the invention, the actuating lever comprises: • a first wall which extends in the radial direction; • a second wall which supports the external perimeter; • an angle of inclination being defined between the first wall and the second wall, the angle of inclination being between 45° and 135°, the angle of inclination preferably being between 80° and 100°.

[0022] Thanks to this latter characteristic, the actuating lever has a bent shape which allows its external periphery to be oriented so that it is arranged axially opposite the axial force exerted by the elastic device of the positioning member.

[0023] According to an additional characteristic of the invention, the first wall is preferably flat and perpendicular to the actuation axis.

[0024] Alternatively, according to another embodiment of the invention, the first wall may be concave or convex in shape, and / or may also have an angle other than 90° relative to the actuation axis.

[0025] According to one aspect of the invention, the second wall extends from the first wall, the outer periphery being radially aligned at least in part with the first wall.

[0026] In this latter embodiment, the actuating lever may be made from a plate folded in two folds, the folding of the second wall being carried out both in the axial direction and in the circumferential direction. The first wall and the second wall may be connected by a third curved connecting wall.

[0027] Alternatively, the first wall and the second wall may be connected by a fixing means known to those skilled in the art, such as in particular a connection by welding, riveting or crimping.

[0028] According to another aspect of the invention, the second wall constitutes a free end independent of the first wall, a junction wall being arranged so as to connect the first wall to the second wall.

[0029] In this latter embodiment, the actuating lever may be made from a plate folded into three folds. In this case, a fourth wall may be arranged to constitute the junction wall connecting the first wall and the second wall. The first wall and the junction wall may be connected by a sixth curved connecting wall. Thus, the folding of the junction wall may be carried out only in the axial direction and the folding of the second wall may be carried out independently and only in the circumferential direction. This embodiment This makes it easier to fold the second wall, which then makes it possible to position the external perimeter more precisely.

[0030] According to another aspect of the invention, the second wall further extends circumferentially around the actuation axis.

[0031] The circumferential orientation of the second wall allows the external periphery to remain axially opposite the bearing face of the positioning member regardless of the angular position of the actuating lever.

[0032] According to an additional characteristic of the invention, the actuating lever is formed in a single piece from a strip of metallic material having a constant thickness, in particular from a steel sheet, the second wall being obtained by folding and the external periphery being obtained from a cut edge of the strip of metallic material.

[0033] Thus, the actuating lever can be produced using a simple and economical manufacturing process.

[0034] According to an additional characteristic of the invention, the positioning member comprises at least one first fixing surface perpendicular to the actuation axis and configured to cooperate with at least one fixing means, in particular a screw.

[0035] This latter characteristic makes it possible to block the positioning member in all directions.

[0036] According to an additional characteristic of the invention, the positioning member further comprises a second fixing surface configured to cooperate with at least one second fixing means, in particular a pin.

[0037] This latter characteristic makes it possible to facilitate the assembly operation, the second fixing means being able, for example, initially to allow the movement of the positioning member to be blocked in a plane perpendicular to the actuation axis, the first fixing means making it possible, in a second stage, to completely immobilize the positioning member.

[0038] According to an additional characteristic of the invention, the first fixing means is capable of being assembled on the transmission casing along a fixing axis parallel to the actuation axis.

[0039] According to an additional characteristic of the invention, the second fixing means is capable of being assembled on the transmission casing along a fixing axis parallel to the actuation axis.

[0040] According to an additional characteristic of the invention, the actuation axis of the actuation lever is parallel to the pivot axis of the movable pawl.

[0041] Thanks to these last three characteristics, the assembly can be further simplified because all the components of the locking mechanism can be mounted on the Transmission housings can be mounted along parallel axes, so they can all be mounted during the same assembly operation.

[0042] According to an additional characteristic of the invention, the positioning member is fixed to the transmission casing.

[0043] According to an additional characteristic of the invention, the actuating lever is pivotally mounted on the transmission casing.

[0044] According to an additional characteristic of the invention, the movable pawl is pivotally mounted on the transmission casing.

[0045] According to an additional characteristic of the invention, the transmission casing comprises bearing surfaces positioned by complementary shape opposite the first and / or second fixing surfaces of the positioning member.

[0046] According to an additional characteristic of the invention, the actuating lever is manufactured from a metal which has undergone a hardening treatment, in particular carbonitriding, nitriding, carburizing or quenching.

[0047] This feature makes it possible to increase the mechanical resistance of the actuating lever necessary to resist the mechanical stresses transmitted to the locking mechanism.

[0048] According to an additional characteristic of the invention, the elastic device axially performs an axial displacement when the positioning member cooperates with the external periphery of the actuating lever, the axial displacement varying between 1 and 10 mm whatever the angular position of the actuating lever.

[0049] According to another embodiment of the invention, the positioning member is a spring pusher, the spring pusher comprising a helical spring exerting a force on a ball, said ball cooperating with the external periphery of the actuating lever.

[0050] According to an additional characteristic of the invention, the actuating lever is driven in rotation, directly or indirectly, by a rotor shaft of an electric motor.

[0051] According to another of its aspects, the invention relates to a transmission system comprising a transmission casing, a shaft equipped with at least one locking recess and a locking mechanism as described previously.

[0052] The invention further relates to a motor vehicle comprising a transmission system as defined above. Brief description of the figures

[0053] [Fig-1] [Fig.l] is a front view of a locking mechanism according to a first embodiment of the invention.

[0054] [Fig.2] [Fig.2] is a perspective view of [Fig.l].

[0055] [Fig.3] [Fig.3] is a perspective view of a portion of the locking mechanism according to a first embodiment of the invention.

[0056] [Fig.4] [Fig.4] is a side view of [Fig.3].

[0057] [Fig.5] [Fig.5] is a perspective view of a positioning member according to a first embodiment of the invention.

[0058] [Fig.6] [Fig.6] is a perspective view of an actuating lever according to a first embodiment of the invention.

[0059] [Fig.7] [Fig.7] is a perspective view of part of the locking mechanism according to a second embodiment of the invention.

[0060] [Fig.8] [Fig.8] is a perspective view of an actuating lever according to a second embodiment of the invention. Description of the embodiments

[0061] In all the figures, identical elements or elements providing the same function bear the same reference numbers. 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 characteristics apply only to a single embodiment. Single characteristics of different embodiments can also be combined or interchanged to provide other embodiments.

[0062] A mechanism for locking the rotation of a shaft of a vehicle comprises in particular: a movable pawl, a thrust device, an actuating lever and a positioning member. The locking mechanism is intended in particular to immobilize a vehicle, for example a car, in a parked state. The various elements of the locking mechanism embodiment will be presented below.

[0063] Figures 1 and 2 illustrate a locking mechanism according to a first embodiment of the invention. In these figures, the locking mechanism comprises a movable pawl 34 located in a transmission housing 1 (partially shown). The movable pawl 34 may be of elongated shape and may have a first end 71 and a second end 72 distant from the first end 71.

[0064] The first end 71 allows for example the fixing of the movable pawl 34 on the transmission casing 1 while allowing the rotational movement of said movable pawl 34. That is to say that the movable pawl is pivotally mounted in a plane P around a pivot axis Yl.

[0065] The second end 72 may comprise a cam surface 36 located on a first lateral face of the movable pawl 34. The second end 72 may further comprise a locking finger 35 projecting from a second lateral face of the movable pawl 34. The locking finger 35 is intended, when the locking mechanism is engaged, to be inserted into a locking recess 45. The locking recess 45 is for example located on a ratchet wheel 44 which is capable of receiving said locking finger 35, and which is fixed in rotation with the transmission shaft 60 (partially shown) intended to be locked in rotation.

[0066] Thus, the locking mechanism varies between a locking position in which the locking finger 35 is engaged in the locking recess 45 and a released position in which the locking finger 35 is disengaged from said locking recess 45. In Figures 1 and 2, the mechanism for locking the rotation of a shaft is shown in a released position.

[0067] The movable pawl 34 may further comprise a torsion spring 50. The torsion spring 50 is for example wound at the first end 71 of the movable pawl 34. The torsion spring 50 may comprise a first end 51 which bears against a bearing surface of the transmission casing 1 and a second end 52 which bears against a bearing surface of the movable pawl 34. The torsion spring 50 is arranged to exert a return force on the movable pawl 34 in order to return it to the released position.

[0068] The locking mechanism further comprises a thrust device 38. The thrust device 38 can be guided in a longitudinal direction X by a guide rail 27 housed in the transmission casing 1. In cases where the thrust device 38 is returned back by the movable pawl 34 during dynamic phases, the thrust device 38 can come into abutment against a side wall of the guide rail 27, which thus forms a non-return stop for the thrust device 38. The thrust device 38 is in this case sent against the movable pawl 34 by a return force exerted by a tension spring 40. This effect can occur for example during attempts to engage at too high a speed. Beyond a threshold speed, for example between 3 km / h and 5 km / h, the movable pawl 34 rebounds to prevent engagement, the thrust device 38 is then returned to the stop.The spring 40 surrounds a rod 39 of the thrust device which extends through a first notch 25 of the transmission casing 1 and a second notch 32 of the guide rail 27.

[0069] The pushing device 38 may be in the form of a mobile carriage which comprises, for example, a first mobile roller 41 capable of moving along a longitudinal wall 30 of the guide rail 27. The pushing device 38 may further comprise a cam follower 42 comprising a second mobile roller which is in contact with the cam surface 36 of the mobile pawl 34 and capable of moving along this cam surface 36.

[0070] The pushing device 38 may further comprise a lug 43 located at the second end of the movable pawl 34. The lug 43 is intended to retain the pawl mobile 34 in the P plane.

[0071] To move the movable pawl 34 into the locking position, the rod 39 can be moved through the second notch 32 of the guide rail 27, thereby moving the pushing device 38 in the longitudinal direction X. The movement of the pushing device 38 can cause the first movable roller 41 to move along the guide rail 27 and the cam follower 42 to move along the cam surface 36 of the movable pawl 34. The cam surface 36 can have a slope, and the pushing device 38 can therefore exert, via its movement, pressure in the direction of the cam surface 36 of the movable pawl 34. This pressure can cause the second end of the movable pawl 34 to rotate in the direction of a locking recess, such that the locking finger 35 can engage in a locking recess present, for example, on a ratchet wheel 44.

[0072] Figures 3 to 6 illustrate more particularly an actuating lever 3 and a positioning member 2 of the locking mechanism according to a first embodiment of the invention.

[0073] The actuating lever 3 is pivotally mounted about an actuating axis Y2 on the transmission casing 1. A housing 101 (visible in [Fig.2]) arranged in the transmission casing 1 can cooperate with a stop ring 102 in order to axially block the actuating lever 3. The actuating lever 3 can be driven in rotation by a drive shaft 303, the drive shaft 303 cooperating in rotation with a rotor shaft of an electric motor, in particular via gears making it possible to achieve a speed reduction. The actuating lever 3 can be guided in rotation relative to the transmission casing 1 by means of a guide bearing 307. The guide bearing 307 can be of the plain bearing, roller bearing or ball bearing type. The guide bearing 307 is configured to absorb the radial and axial forces, as well as the bending moments which are exerted on the actuating lever 3 and the drive shaft 303.The actuating lever 3 may be connected to the rod 39, for example via a pivot connection, such that a rotation of the actuating lever 3 around the actuating axis Y2 causes a translation in the longitudinal direction X of the pushing device 38.

[0074] As illustrated in [Fig.6], the actuating lever 3 further comprises an external periphery 300 comprising a first angular positioning notch 301 and a second angular positioning notch 302.

[0075] The actuating lever 3 may comprise a first wall 305 perpendicular to the actuating axis Y2 and a second wall 304 extending axially in a direction parallel to the actuating axis Y2. Thus, an inclination angle A of 90° may be formed between the first wall 305 and the second wall 304. The second wall 304 supports the outer periphery 300. The second wall 304 extends from the first wall 305, a third curved connecting wall 306 connecting the first wall 305 to the second wall 304. The second wall 304 further extends circumferentially around the actuation axis Y2. The second wall 304 is positioned radially in the extension of the first wall 305. Thus, the actuation lever 3 can have a bent shape which makes it possible to orient its outer periphery 300 so that it is arranged axially opposite the axial force exerted by the positioning member 2.

[0076] In the embodiment of [Fig. 6], it is provided that the actuating lever 3 is formed in one piece from a steel strip having a constant thickness, for example a thickness of between 3 and 6 mm, the second wall 304 being obtained by folding and the external periphery 300 being obtained from a cutting edge of the steel strip. The actuating lever 3 can then undergo a hardening treatment in order to increase its mechanical strength.

[0077] As illustrated by Figures 3 and 5, the positioning member 2 cooperates with the external periphery of the actuating lever 3, the positioning member 2 comprises a bearing surface 204 configured to engage in the first angular positioning notch 301 when the movable pawl 34 is in the locking position and in the second angular positioning notch 302 when the movable pawl 34 is in the released position. The positioning member 2 thus makes it possible to maintain the position of the locking mechanism in a stable and precise manner in the released position and / or in the locking position.

[0078] The positioning member 2 comprises an elastic device 200 exerting a force, directly or indirectly, on the external periphery 300 in a direction parallel to the actuation axis Y2. The elastic device 200 may be a flexible blade 200 which deforms elastically and axially when the positioning member 2 moves on the external periphery 300 of the actuation lever 3. A rolling element 203, for example a cylindrical roller, arranged on the flexible blade 200 may be configured to roll on the external periphery 300 of the actuation lever 3.

[0079] In an embodiment not shown, the positioning member 2 may be a spring pusher. In this case, the elastic device 200 may be a helical spring and the rolling element 203 may be a ball cooperating with the external periphery 300 of the actuating lever 3.

[0080] As illustrated in [Fig.5], the positioning member 2, and more particularly the flexible blade 200, may comprise a first fixing surface 201 perpendicular to the actuation axis Y2 and configured to cooperate with a fixing means 205, here a screw 205, in order to block the movements relative to the casing of transmission 1 in all directions. A reinforcing plate 212 can be placed between the head of the screw 205 and the flexible blade 200 in order to distribute the pressure induced by the tightening of the screw 205. A second fixing means 206, here a cylindrical centering pin 206 (visible in [Fig. 4]) inserted in the transmission casing 1, can further cooperate with the flexible blade 200, via for example a circular hole made in it, to facilitate the assembly of the positioning member 2 by blocking, before the screwing operation of the screw 205 is carried out, the movement of the positioning member 2 in a plane perpendicular P to the actuation axis Y2. In addition, in order to further facilitate the positioning of the positioning member 2, the transmission casing 1 can comprise a housing 103 (visible in [Fig.2]) having support surfaces positioned by complementary shape opposite the first fixing surface 201 and the external edges of the elastic device 200 of the positioning member 2. .

[0081] As illustrated in [Fig.4], four axes can be defined to carry out the assembly on the transmission casing 1: the actuation axis Y2 of the actuation lever 3, the pivot axis Y1 of the movable pawl 34, a third axis Y3 along which the screw 205 can be assembled and a fourth axis Y4 along which the centering pin 206 can be assembled. Advantageously, these four axes can be parallel, which makes it possible to easily mount all these components during the same assembly operation.

[0082] Figures 7 and 8 illustrate an actuating lever 3 according to a second embodiment of the invention. Here, the actuating lever 3 may comprise a first wall 305 perpendicular to the actuating axis Y2 and a second wall 304 extending axially in a direction parallel to the actuating axis Y2. The second wall 304 is configured to support the external periphery 300. The second wall 304 further extends circumferentially around the actuating axis Y2. The second wall 304 is positioned circumferentially offset from the first wall 305. A fourth wall 308 may be arranged to constitute a connecting wall 308 between the first wall 305 and the second wall 304. The first wall 305 and the connecting wall 308 may be connected by a sixth curved connecting wall 309.The shape of the actuating lever 3 according to this embodiment can be obtained from a strip of steel cut then folded a first time axially to constitute the junction wall 308 and then folded a second time circumferentially to constitute the second wall 304.

[0083] It is emphasized that all the characteristics, as they emerge for a person skilled in the art from the present description, the drawings and the attached claims, even if concretely they have only been described in relation to other determined features, both individually and in any combinations, may be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances make such combinations impossible or meaningless.

[0084] The use of the verb “comporter”, “comprendre” and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0085] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

1. Claims Locking mechanism suitable for being mounted in a transmission housing (1) of a vehicle for locking in rotation a shaft equipped with at least one locking recess (45), the locking mechanism comprising: • a movable pawl (34) comprising a locking finger (35), the movable pawl (34) being pivotally mounted about a pivot axis (Yl) between a locking position in which the locking finger (35) is engaged in the locking recess (45) and a released position in which the locking finger (35) is disengaged from said locking recess (45), the movable pawl (34) comprising a cam surface (36); • a pushing device (38) comprising a cam follower (42) capable of moving on the cam surface (36) in order to move the movable pawl (34) from the released position to the locking position; • an actuating lever (3) pivotally mounted about an actuating axis (Y2) and configured to move the pushing device (38), the actuating lever (3) comprising an external periphery (300) comprising a first angular positioning notch (301) and a second angular positioning notch (302); and • a positioning member (2) cooperating with the external periphery (300) of the actuating lever (3), the positioning member (2) comprising a bearing surface (204) configured to engage in the first angular positioning notch (301) when the movable pawl (34) is in the locking position and in the second angular positioning notch (302) when the movable pawl (34) is in the released position; characterized in that the positioning member (2) further comprises an elastic device (200) exerting a force, directly or indirectly, on the external periphery (300) in a direction parallel to the actuation axis (Y2).

2. A locking mechanism according to claim 1, wherein the elastic device (200) is a flexible blade which deforms elastically and axially when the positioning member (2) moves on the outer periphery (300) of the actuating lever (3).

3. A locking mechanism according to claim 1 or 2, wherein the positioning member (2) further comprises a rolling element (203) arranged on the elastic device (200), the rolling element (203) being configured to roll on the outer periphery (300) of the actuating lever (3).

4. A locking mechanism according to any preceding claim, wherein the actuating lever (3) comprises: • a first wall (305) which extends in the radial direction; • a second wall (304) which supports the outer periphery (300); an angle of inclination (A) being defined between the first wall (305) and the second wall (304), the angle of inclination (A) being between 45° and 135°, the angle of inclination (A) preferably being between 80° and 100°.

5. A locking mechanism according to claim 4, wherein the second wall (304) extends from the first wall (305), the outer periphery (300) being radially aligned at least in part with the first wall (305).

6. A locking mechanism according to claim 4, wherein the second wall (304) constitutes a free end independent of the first wall (305), a joining wall (308) being arranged so as to connect the first wall (305) to the second wall (304).

7. A locking mechanism according to any one of claims 4 to 6, wherein the second wall (304) further extends circumferentially around the actuation axis (Y2).

8. A locking mechanism according to any one of claims 4 to 7, wherein the actuating lever (3) is formed in one piece from a strip of metallic material having a constant thickness, in particular from a steel sheet, the second wall (304) being obtained by folding and the external periphery (300) being obtained from a cut edge of the strip of metallic material.

9. A locking mechanism according to any one of the preceding claims. preceding, in which the positioning member (2) comprises at least one first fixing surface (201) perpendicular to the actuation axis (Y2) and configured to cooperate with a first fixing means (205), in particular a screw.

10. Locking mechanism according to claim 9, in which the first fixing means (205) is capable of being assembled on the transmission casing (1) along a fixing axis (Y3) parallel to the actuation axis (Y2).

11. A locking mechanism according to any preceding claim, wherein the actuating axis (Y2) of the actuating lever (3) is parallel to the pivoting axis (Yl) of the movable pawl (34).

12. A transmission system comprising a transmission housing (1), a shaft (44) equipped with at least one locking recess (45) and a locking mechanism according to any one of claims 1 to 11.

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