Locking mechanism

Abstract

The invention relates to a locking mechanism comprising: - a transmission housing (1); - a movable pawl (34) comprising a locking finger (35), the movable pawl being pivotally mounted about an axis on the transmission housing between a locked 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; - an actuator (37) that moves a thrust device (38) guided by a guide rail (27), in which the thrust device includes a cam follower adapted to move on the cam surface; - a housing (2) formed in the transmission housing having a positioning slot into which a wall of the guide rail is inserted. (Shorthand figure: 8)

Description

Title of the invention: Locking mechanism technical field

[0001] The present invention relates to a locking mechanism for locking against rotation 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 motor vehicle when stationary. In such a case, they prevent the rotation of a motor vehicle's drive shaft. Such locking mechanisms are notably used in motor vehicles with automatic transmissions, hybrid vehicles, and electric vehicles.

[0003] It is known, notably from document FR3128754, of locking mechanisms comprising a ratchet equipped with a locking pin and pivotally mounted on a transmission housing between a released position and a locked position in which the locking pin is inserted into a locking recess that is rotationally fixed to the transmission shaft to be locked. The locking mechanism further includes an actuator that moves a movable carriage which is guided in translation on the transmission housing by means of a guide rail. The movable carriage has a roller that cooperates with a cam surface of the ratchet so that a translational movement of the movable carriage causes the ratchet to pivot. The guide rail is a stamped sheet metal part having several folded walls allowing it to be positioned by fitting into a recess provided in the transmission housing.More specifically, the guide rail has four walls bent at a 90-degree angle to obtain an overall rectangular shape and, correspondingly, the housing has four machined faces opposite the four walls of the guide rail to ensure their positioning.

[0004] Such a locking mechanism structure is of simple design, easy to assemble and robust enough to withstand the significant mechanical stresses that may occur during the transition from the released position to the locked position.

[0005] However, such a structure poses several technical problems: • the guide rail, due to its large number of folded walls, has a complex shape that is difficult to manufacture; • The creation of the surfaces of the guide rail housing in the casing requires a large amount of material removal by machining; • The positioning of the guide rail relative to its housing in the casing is not precise enough because it depends on the sum of the manufacturing tolerances of a large number of geometric dimensions.

[0006] Thus, it is necessary to propose a locking mechanism that is more economical, easier to implement and allows the guide rail to be positioned more precisely. Summary

[0007] In all that follows, ordinal numeral adjectives are used to differentiate features. They do not define the position of a feature. Therefore, for example, a third feature of a product does not mean that the product has a first and / or a second feature.

[0008] One idea underlying the invention is a locking mechanism intended to lock a vehicle shaft in rotation.

[0009] An idea underlying the invention is a blocking mechanism that makes it possible to solve one or more technical problems of the prior art, for example the aforementioned problems.

[0010] The invention relates to a locking mechanism capable of locking the rotation of a shaft of a vehicle equipped with at least one locking recess, the locking mechanism comprising:

[0011] - a movable ratchet comprising a locking finger, the movable ratchet being mounted pivoting in a plane about a pivot axis on the transmission housing 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;

[0012] - an actuator that moves a thrusting device, the thrusting 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 locked position;

[0013] - a guide rail comprising a guide wall guiding the movement of the thrusting device and a positioning wall;

[0014] - a transmission housing comprising a housing, the housing comprising a first positioning face and a second positioning face, the first positioning face and the second positioning face forming a positioning slot;

[0015] the positioning wall of the guide rail being inserted into the positioning slot of the housing.

[0016] Thanks to these characteristics, a very precise positioning of the guide rail in a chosen direction of the plane is ensured because this positioning does not depend only and directly involves two dimensions: that of the positioning wall and that of the slot. Furthermore, the slot can be created economically by simply passing a machining tool through it, thus significantly reducing the amount of machining required in the housing.

[0017] According to a further feature of the invention, the housing is formed of material in the transmission casing.

[0018] According to a further feature of the invention, the slot is made by a single machining operation using a cutting tool intended to machine the grooves, such as in particular a disc cutter, an end mill or a grooving tool.

[0019] According to an additional feature of the invention, the thrusting device is in the form of a movable carriage comprising a first movable roller adapted to move along the guide wall of the guide rail and a second movable roller adapted to move on the cam surface of the movable pawl.

[0020] Thanks to these characteristics, when the moving carriage is in relative motion with respect to the guide rail, the friction forces between the moving carriage and the guide rail are reduced. Thus, the movement of the moving carriage is ensured without wear on the moving carriage or the guide rail.

[0021] According to an additional feature of the invention, the thrust device is in the form of a one-piece tip, for example with a rounded or conical end, the one-piece tip being able to move on the one hand on the guide wall of the guide rail and on the other hand on the cam surface of the movable pawl.

[0022] Thanks to this feature, the function of the push device is achieved with a small number of components and therefore a reduced cost.

[0023] According to a further feature of the invention, the positioning wall and the guide wall form a single wall, the positioning wall having at least one protrusion extending substantially in a direction parallel to the movement of the thrust device, the at least one protrusion being opposite the first positioning face and / or the second positioning face of the housing.

[0024] According to a further feature of the invention, the positioning wall and the guide wall form a single wall, the positioning wall having at least two protrusions extending substantially in a direction parallel to the movement of the thrust device from the guide wall, the at least two protrusions being opposite the first positioning face and / or the second positioning face of the housing.

[0025] This feature offers several advantages: • The single wall gives the guide rail a simple shape to manufacture, without bends or complex geometric join areas between the guide wall and the positioning faces; • The guide wall is held directly by the slot in the housing, thus allowing precise positioning of the push device relative to the ratchet in order, on the one hand, to guarantee the reliability of the locking and, on the other hand, to prevent excessive forces from passing through the locking mechanism and thus being likely to damage it.

[0026] The protrusions of the positioning wall are preferably smaller than those of the guide wall; for example, the largest surface area of ​​a protrusion on the positioning wall is 10% to 30% smaller than the largest surface area of ​​the guide wall. These small protrusions allow for a reduction in positioning and flatness defects of the positioning wall during the manufacturing of the guide rail. These small protrusions also limit the risk of the guide rail jamming during assembly in the positioning slot of the housing.

[0027] According to a further feature of the invention, the first positioning face of the housing and the second positioning face of the housing are parallel.

[0028] Thanks to this feature, the bearing surface between the housing positioning slot and the guide rail positioning wall is increased to allow sufficient absorption of the forces passing through the locking mechanism.

[0029] According to an additional feature of the invention, a width of the positioning slot, a thickness of the positioning wall and an operating clearance equal to the difference between the width and the thickness are defined, the value of the operating clearance being between 0.05 and 1 mm, the value of the operating clearance preferably being between 0.2 and 0.6 mm.

[0030] Thanks to the features of the invention, ease of implementation is improved because it depends directly on the machining tolerance of the slot and the thickness tolerance of the guide wall. As a result, the tolerance of the operating clearance value is reduced, which increases the positioning accuracy of the guide rail.

[0031] In the case where the first positioning face of the housing and the second positioning face of the housing are not parallel, the width of the slot is understood as the smallest distance existing between the first positioning face of the housing and the second positioning face of the housing.

[0032] According to a further feature of the invention, the housing has a first lateral face opposite and distant from a second lateral face and a first longitudinal face located between the first lateral face and the second face lateral, in which the guide rail presents correspondingly to the housing a third lateral face opposite and distant from a fourth lateral face and the guide wall extending longitudinally between the third lateral face and the fourth lateral face, and in which the third lateral face, the fourth lateral face and the guide wall of the guide rail are respectively opposite the first lateral face, the second lateral face and the first longitudinal face of the housing in order to limit a displacement of the guide rail in all directions of the plane.

[0033] This arrangement is particularly advantageous because the various pressure forces exerted on the guide rail are absorbed by the faces of the housing and therefore by the transmission casing. This arrangement makes it possible to maintain the dimensions of the guide rail, reducing its deformation and therefore its deterioration over time.

[0034] This feature also allows for the simple and economical assembly and positioning of the guide rail in the housing. The faces of the housing can be obtained, for example, by machining. The third lateral faces and fourth faces of the guide rail can each be obtained, for example, by a bending operation from a sheet of metal.

[0035] According to an additional feature of the invention, an assembly gap is formed between the first lateral face and the third lateral face, between the second lateral face and the fourth lateral face and between the first longitudinal face and the guide wall, said assembly gap preferably being between 0.2 and 1 mm.

[0036] This feature makes it possible to choose an assembly set that is, on the one hand, small enough to limit the movement of the guide rail in the housing, and on the other hand, large enough to allow the effortless insertion of the guide rail into the housing during the assembly operation.

[0037] According to a further feature of the invention, the guide rail is mounted tightly in the housing by means of a snap-fit ​​connection

[0038] According to an additional feature of the invention, the guide rail is mounted tightly in the housing by the interposition of a pre-stressed elastic piece between the guide rail and the housing.

[0039] According to a further feature of the invention, the guide rail has two tabs bent at an angle of 90 degrees to the guide wall, each bent tab forming a side wall which supports one of the two side faces of the guide rail.

[0040] According to a further feature of the invention, the guide rail comprises a single tab bent at an angle of 90 degrees to the guide wall, the bent tab forming a side wall which supports the third lateral face of the guide rail, a cut-out slice the thickness of the guide wall forming the fourth lateral face of the guide rail.

[0041] According to an additional feature of the invention, a first slice of the thickness of the guide wall forms the third lateral face of the guide rail, a second slice of the thickness of the guide wall forms the fourth lateral face of the guide rail.

[0042] According to an additional feature of the invention, the guide rail is flat, a first cut-out slice of the thickness of the guide wall forming the third lateral face of the guide rail, a second cut-out slice of the thickness of the guide wall forming the fourth lateral face of the guide rail.

[0043] According to an additional feature of the invention, the guide rail comprises exclusively the guide wall, a first side wall and / or a second side wall.

[0044] This last characteristic implies that the guide rail does not have a bottom or a ceiling.

[0045] According to an additional feature of the invention, the guide wall, the first side wall and / or the second side wall of the guide rail has a thickness of between 1.5mm and 3.5mm; preferably between 2.5 and 3mm.

[0046] According to an additional feature of the invention, all the walls of the guide rail are perpendicular to the plane.

[0047] According to an additional feature of the invention, the housing is machined in dimensions chosen so as to position the guide rail and to limit a displacement of said guide rail in all directions of the plane.

[0048] According to an additional feature of the invention, the housing has a height between 15 mm and 30 mm.

[0049] According to an additional feature of the invention, the walls of the housing bearing the first longitudinal face, the first lateral face and the second lateral face have a thickness of between 3 and 10 mm.

[0050] According to a further feature of the invention, the walls of the housing bearing the first longitudinal face, the first lateral face and the second lateral face may have stiffeners oriented perpendicularly to the first longitudinal face and / or to the first lateral face and / or to the second lateral face, the stiffeners being for example of triangular shapes,

[0051] This feature makes it possible to increase the resistance of the housing under the forces passing through the locking mechanism.

[0052] According to a further feature of the invention, the housing is manufactured by a casting process, in particular an aluminum or magnesium casting process.

[0053] According to a further feature of the invention, the first lateral face of the housing and / or the second lateral face of the housing do not have an edge common with the first longitudinal surface of the housing, the first lateral face of the housing, the second lateral face of the housing and the first longitudinal surface of the housing being obtained by a machining process and connected to each other by walls of raw material.

[0054] This feature makes it possible to reduce the amount of material to be machined. In the invention, raw material means material that has not been machined. For example, the raw material may come from a casting process. Advantageously, the minimum distance in the longitudinal direction between the first longitudinal surface of the housing and the first lateral face of the housing and / or between the first longitudinal surface of the housing and the second lateral face of the housing may be greater than or equal to the radius of the milling tool used for the machining process.

[0055] According to a further feature of the invention, the walls of the guide rail and / or the walls of the housing may have chamfers or grooves to facilitate, during the assembly operation, the insertion of the guide rail into the housing in the direction perpendicular to the plane

[0056] According to an additional feature of the invention, the housing has a height between 15 mm and 30 mm.

[0057] According to a further feature of the invention, the housing has a first notch and the guide rail has a second notch, the first notch of the housing and the second notch of the guide rail being through and intended to allow the passage of the actuator.

[0058] According to a further feature of the invention, the shape of the first notch and / or the second notch is chosen from: a recess, a cutout, an oblong hole, a groove or a slot.

[0059] According to a further feature of the invention, the first notch of the housing is located on the first lateral face of the housing and the second notch of the guide rail is located on the third lateral face of the guide rail.

[0060] According to an additional feature of the invention, the guide rail includes a backstop and / or an end stop preventing the pushing device from moving beyond said guide rail.

[0061] Thanks to these features, the push device is held in the housing.

[0062] According to an additional feature of the invention, the anti-return stop is made by the third lateral face of the guide rail and / or the end-of-stroke stop is made by the fourth lateral face of the guide rail.

[0063] According to a further feature of the invention, the housing positioning slot further comprises at least one bottom face parallel to the plane and, correspondingly, the guide rail positioning wall further comprises at least one lower face parallel to the plane, the at least one lower face being opposite at least one bottom face so as to limit the movement of the guide rail in a direction perpendicular to the plane.

[0064] According to an additional feature of the invention, a fixing means secures the guide rail to the transmission housing, the fixing means blocking movement of the guide rail in a direction perpendicular to the plane.

[0065] According to an additional feature of the invention, the fastening means is for example: a screw, a screw and nut system, a rivet, an adhesive material, a stop attached to the housing or a stop obtained by plastic deformation of the housing.

[0066] According to a further feature of the invention, the guide rail is formed in one piece from a folded strip of metallic material, in particular from a sheet of steel.

[0067] According to an additional feature of the invention, the guide rail is formed in one piece by a sintering process of a metallic material.

[0068] According to an additional feature of the invention, the guide rail is formed in one piece by a molding process of a metallic material.

[0069] According to a further feature of the invention, the guide rail is made of a metal which has undergone a hardening treatment, in particular carbonitriding, nitriding, carburizing or quenching.

[0070] This feature makes it possible to increase the mechanical resistance of the guide rail necessary to resist the stresses transmitted to the locking mechanism.

[0071] The invention also relates to a transmission system comprising a shaft equipped with at least one locking recess and a locking mechanism as defined above.

[0072] According to a further feature of the invention, the shaft includes a wheel having at least one locking recess. For example, the wheel is a ratchet wheel.

[0073] According to an additional feature of the invention, the wheel has 1 to 12 locking recesses.

[0074] According to a further feature of the invention, the recesses are regularly spaced from each other.

[0075] The invention further relates to a motor vehicle comprising a transmission system as defined above. Brief description of the figures

[0076] [Fig. 1] The [Fig. 1] is a front view of a portion of a transmission housing comprising a housing for the guide rail according to a first embodiment.

[0077] [Fig.2] The [Fig.2] is a perspective view of the housing of the [Fig.1].

[0078] [Fig. 3] Fig. 3 is a front view of a portion of a transmission housing including a housing and a guide rail according to a first embodiment.

[0079] [Fig.4] The [Fig.4] is a perspective view of the portion of the housing and the guide rail of the [Fig.3].

[0080] [Fig.5] The [Fig.5] is a first perspective view of the guide rail illustrated in figures 3 and 4.

[0081] [Fig.6] Fig.6 is a second perspective view of the guide rail illustrated in Figures 3 and 4.

[0082] [Fig.7] The [Fig.7] is a schematic side view of the portion of the housing and guide rail of the [Fig.4].

[0083] [Fig.8] The [Fig.8] is a front view of a portion of the locking mechanism according to a first embodiment.

[0084] [Fig.9] The [Fig.9] is a perspective view of the locking mechanism of the [Fig.8].

[0085] [Fig. 10] Fig. 10 is a perspective view of a dwelling according to a second method of implementation.

[0086] [Fig. 11] The [Fig. 11] is a perspective view including the guide rail inserted into the housing of the [Fig. 10].

[0087] [Fig. 12] The [Fig. 12] is a perspective view of a shaft of a vehicle locked in rotation. Description of the implementation methods

[0088] In all the figures, identical elements or elements performing the same function are identified by the same reference numerals. The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference numeral relates to the same embodiment or that the features apply only to a single embodiment. Simple features from different embodiments can also be combined or interchanged to provide other embodiments.

[0089] A mechanism for locking the rotation of a vehicle shaft includes, in particular: a movable pawl, an actuator, a thrust device, a guide rail, and a housing comprising a recess. The locking mechanism is intended, in particular, to immobilize a vehicle, for example a car, in a parked position.

[0090] The different elements of the locking mechanism according to different embodiment variants will be presented below.

[0091] Figures 1 and 2 illustrate a transmission housing 1 (partially shown) comprising a housing 2 for the locking mechanism of a vehicle according to a first embodiment.

[0092] Housing 2 is, for example, formed in the transmission housing 1, that is to say that the housing is not a separate part which is fixed to the transmission housing 1. Indeed, the housing 2 can be hollowed out or manufactured directly, for example by a casting process, in the thickness of a wall of the transmission housing 1.

[0093] Housing 2 is intended to house and position a guide rail, illustrated in particular in Figures 3, 4 and 5. Housing 2 has, for example, a general "L" shape with rounded edges

[0094] The housing 2 comprises a first lateral face 21 opposite and distant from a second lateral face 22. The housing 2 further comprises longitudinally a first positioning face 23 opposite two second positioning faces 24 and 24'. The two second positioning faces 24 and 24' may be in the same plane and may be parallel to the first positioning face 23 to form a positioning slot.

[0095] Figures 3 and 4 illustrate a portion of a transmission housing 1 comprising the housing 2 as shown in Figures 1 and 2 and further illustrate a guide rail 27 housed in the housing 2.

[0096] The guide rail 27 has dimensions similar to the housing 2 in order to be inserted into the housing 2, i.e., the guide rail 27 follows the contour of the housing 2. Thus, the guide rail is held in a static position in the housing 2 in a plane P comprising a longitudinal direction X and a transverse direction Y perpendicular to the longitudinal direction X. In this arrangement, the various pressure forces exerted on the guide rail 27 can be absorbed by the faces of the housing 2 and therefore by the transmission housing 1.

[0097] As illustrated in particular in figures 4, 5 and 6, the guide rail 27 may include a positioning wall comprising two protrusions 300 and 300' opposite the first positioning face 23 on the one hand and the two second positioning faces 24 and 24' on the other hand, to fit into the positioning slot of the housing 2 and thus position the guide rail along the transverse direction Y.

[0098] In a manner analogous to the housing 2 as illustrated in Figures 1 and 2, the guide rail 27 illustrated in Figures 5 and 6 may have a third lateral face 28 opposite and distant from a fourth lateral face 29 as well as a guide wall 30 extending longitudinally between the third lateral face 28 and the fourth lateral face 29.

[0099] The third lateral face 28, the fourth lateral face 29 and the guide wall 30 of the guide rail 27 can be respectively opposite the first lateral face 21, the second lateral face 22 and the first longitudinal face 23 of the housing 2 in order to prevent a movement of the guide rail 27 in all directions of the plane P.

[0100] The two protrusions 300 and 300' can extend longitudinally and form with the guide wall 30 a single wall 301. The single wall 301 can be flat.

[0101] As illustrated by Figures 2, 4, 6 and 7, the positioning slot of the housing 2 may have two bottom faces 47, 47' parallel to the plane P and, correspondingly, the two protrusions 300 and 300' of the guide rail 27 may have two lower faces 31,31' parallel to the plane P, the two lower faces 31,31' being opposite the two bottom faces 47, 47' so as to limit the movement of the guide rail in a direction perpendicular to the plane P.

[0102] As schematically illustrated in [Fig. 7], an operating clearance equal to the difference between the width L of the positioning slot and the thickness e of the positioning wall 300 is defined. The value of the operating clearance can be on the order of 0.2 to 0.6 mm.

[0103] In addition, the first side face 21 of the housing 2 may include a first notch 25 intended to allow the passage of an actuator which is illustrated in Figures 8 and 9. The first notch 25 has, for example, a "U" shape.

[0104] The third lateral face 28 of the guide rail 27 may include a second notch 32 having a shape corresponding to that of the first notch 25 of the housing 2, as illustrated in [Fig. 4]. The second notch 32 is intended, for example, to allow the passage of an actuator 37, which is shown in Figures 8 and 9.

[0105] The third lateral face 28 of the guide rail 27 can be a non-return stop for the thrust device 38, illustrated by figures 8 and 9, so that the thrust device is retained in translation along the axis X in the housing 2, by the guide rail 27.

[0106] The guide rail 27 serves to guide the push device 38 and may be designed to perform only the translational movement necessary to actuate a locking finger in a locking recess so that the locking mechanism is in a locked position. The locked position allows, for example, the parking of a motor vehicle.

[0107] The guide rail can be made, for example, from a strip of metallic material which is first cut to form the second notch 32 and then folded twice lengthwise to form the walls that compose it. The metal strip before folding can also include a notch for forming the second notch 32 of the guide rail. The thickness of the metal strip is, for example, on the order of 3 mm.

[0108] Figures 8 and 9 represent partial views of a mechanism for locking a shaft in rotation in a released position.

[0109] The locking mechanism comprises the housing 2 as shown in Figures 1 to 4 and the guide rail 27 as shown in figures 3 to 6. The locking mechanism may further include a movable ratchet 34 located in the transmission housing 1.

[0110] The movable ratchet 34 can be elongated in shape and can have a first end 71 and a second end 72 distant from the first end 71.

[0111] The first end 71 allows, for example, the fixing of the movable ratchet 34 on the transmission housing 1 while allowing the rotational movement of said movable ratchet 34. That is to say, the movable ratchet is mounted pivotally in a plane P around a pivot axis.

[0112] The second end 72 may be located at the opening 33 of the guide rail 27 and the opening 26 of the housing. The second end 72 may include a cam surface 36 located on a fifth lateral face of the movable pawl 34, facing inwards towards the housing 2. The second end 72 may further include a locking pin 35 projecting outwards from the housing 2 from a sixth lateral face of the movable pawl 34. The locking pin 35 is designed, when the locking mechanism is engaged, to fit into a locking recess 45, shown in [Fig. 12]. The locking recess 45 is, for example, located on a ratchet wheel 44 which is adapted to receive said locking pin 35, as illustrated in [Fig. 12], and which is fixed rotationally to the transmission shaft 60 to be locked in rotation.

[0113] According to a variant shown in [Fig. 12], the movable pawl 34 may further comprise a torsion spring 50. The torsion spring 50 is, for example, wound around the first end 71 of the movable pawl 34. The torsion spring 50 may comprise a first end portion 51 bearing against a bearing surface of the transmission housing and a second end portion 52 bearing against a bearing surface of the movable pawl 34. The torsion spring 50 is arranged to exert a restoring force on the movable pawl 34 in order to return it to the released position. The locking mechanism may further comprise an actuator 37, partially shown in [Fig. 7], which is fixed to the transmission housing 1. The actuator 37 may comprise a rod 39 adapted to move along the longitudinal direction X.

[0114] The rod 39 can extend through the first notch 25 of the housing 2 and the second notch 32 of the guide rail 27 into an internal space of the housing 2. The rod 39 can be fixed to the push device 38 located in the housing 2.

[0115] The thrust device 38 is intended to be guided by the guide rail 27.

[0116] In cases where the push device 38 is returned by the ratchet During dynamic phases, the mobile thrust device 38 34 can come to rest against the third lateral face 28 of the guide rail 27, which thus forms a stop Anti-return mechanism for the push device 38. In this case, the push device 38 is forced against the movable pawl 34 by a restoring force exerted by a tension spring 40 surrounding the rod 39. This spring has one end fixed to the actuator body and a second end fixed to the push device 38. This effect can occur, for example, during attempts to engage the mechanism at excessive speed. Above a threshold speed, for example between 3 km / h and 5 km / h, the movable pawl 34 rebounds to prevent engagement, and the push device 38 is then returned to its stop.

[0117] In the embodiment of Figures 8 and 9, the thrust device 38 may be in the form of a movable carriage which includes, for example, a first movable roller 41 adapted to move along the first longitudinal wall 30 of the guide rail 27. The thrust device 38 may further include a cam follower 42 having a second movable roller which is in contact with the cam surface 36 of the movable pawl 34 and adapted to move along this cam surface 36.

[0118] The thrust device 38 may further include a lug 43 located at the second end of the movable pawl 34. The lug 43 is intended to retain the movable pawl 34 in the plane P.

[0119] To move the movable pawl 34 into the locked position, the rod 39 of the actuator 37 can be moved through the second notch 32 of the guide rail 27, thereby moving the thrust device 38 in a longitudinal direction. The thrust device 38 can be moved from the third lateral face 28 of the guide rail 27 towards the fourth lateral face 29 of the guide rail 27. The movement of the thrust device 38 can cause the first movable roller 41 to move along the first longitudinal wall 30 of 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 may have a slope, and the thrust device 38 can therefore exert pressure, through its movement, in the direction of the cam surface 36 of the movable pawl 34.This pressure can cause a rotational displacement of the second end of the movable pawl 34 towards a locking recess so that the locking finger 35 can engage in a locking recess present for example on a ratchet wheel as illustrated [Fig. 12] in order to lock said ratchet wheel 44.

[0120] Figure 12 illustrates a transmission housing 1 comprising a ratchet wheel 44. The ratchet wheel 44 may have a plurality of regularly spaced recesses 45 around its entire circumference. Each recess 45 of the plurality of recesses may have dimensions enabling the locking finger 35 of the movable pawl 34 to be received. Figure 12 further illustrates a shaft 60 of a vehicle which is locked against rotation by the locking mechanism.

[0121] For moving the locking mechanism from the locked position to the released position, the rod 39 can be moved so as to move the push device 38 towards the third lateral face 28 until it comes to rest against the third lateral face 28 of the guide rail 27. The locking finger 35 can be disengaged from the locking recess present on the ratchet wheel 44 which releases said ratchet wheel and thus allows the rotation of the transmission shaft 60.

[0122] Figures 10 to 11 illustrate a second embodiment of the housing 2 into which the guide rail 27 is inserted. In this embodiment, the manufacturing process has been improved compared to the first embodiment of the housing 2 in [Fig. 2] in order to reduce the amount of material to be removed to manufacture the housing. The first lateral face 21 of the housing and the second lateral face 22 of the housing do not have a common edge with the first longitudinal surface 23 of the housing; the first lateral face 21 of the housing, the second lateral face 22 of the housing, and the first longitudinal surface 23 of the housing are, for example, obtained by a machining process and connected to each other by walls of as-cast material.

[0123] In the embodiment of [Fig. 10], the various walls extending from the housing that support the faces of the housing may be of slightly different thicknesses, varying for example from 4 to 6 mm, in order to promote moldability during the casting process. These walls may include stiffeners (100, 100') oriented perpendicularly to the first longitudinal face 23 and / or the first lateral face 21 and / or the second lateral face 22, the stiffeners being, for example, triangular in shape.

[0124] It is emphasized that all features, as they are apparent to a person skilled in the art from the present description, drawings and attached claims, even if in practice they have only been described in relation to other specific features, both individually and in any combinations, can be combined with other features or groups of features disclosed herein, provided that this has not been expressly excluded or that technical circumstances render such combinations impossible or meaningless.

[0125] 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.

[0126] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Claims

1. A locking mechanism capable of locking in rotation a shaft of a vehicle 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 in a plane (P) about a pivot axis on the transmission casing (1) 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); - an actuator (37) which moves a pushing device (38), the pushing device (38) comprising a cam follower adapted to move on the cam surface (36) in order to move the movable pawl from the released position to the locking position;- a guide rail (27) comprising a guide wall (30) guiding the movement of the pushing device (38) and a positioning wall (300); - a transmission casing (1) comprising a housing (2), the housing (2) comprising a first positioning face (23) and a second positioning face (24, 24'), the first positioning face (23) and the second positioning face (24, 24') forming a positioning slot; the positioning wall (300) of the guide rail (27) being inserted into the positioning slot of the housing (2).;

2. A locking mechanism according to claim 1 wherein the positioning wall (300) and the guide wall (30) form a single wall (301), the positioning wall (300) comprising at least one protrusion (300, 300') extending substantially in a direction parallel to the movement of the pushing device (38) from the guide wall (30), the at least one protrusion (300, 300') being opposite the first positioning face (23) and / or the second positioning face (24, 24') of the housing (2).

3. A locking mechanism according to claim 2, the positioning wall (300) comprising at least two protrusions (300, 300') extending substantially in a direction parallel to the movement of the pushing device (38), the at least two protrusions (300, 300') being opposite the first positioning face (23) and / or the second positioning face (24, 24') of the housing (2).

4. A locking mechanism according to any preceding claim wherein the first positioning face (23) of the housing (2) and the second positioning face (24, 24') of the housing (2) are parallel.

5. A locking mechanism according to any preceding claim wherein a width (L) of the positioning slot, a thickness (e) of the positioning wall (300) are defined, and an operating clearance being equal to the difference between the width (L) and the thickness (e), the value of the operating clearance being between 0.05 and 1 mm, the value of the operating clearance preferably being between 0.2 and 0.6 mm.

6. A locking mechanism according to any preceding claim, wherein the housing (2) has a first lateral face (21) facing and spaced from a second lateral face (22) and a first longitudinal face (23) located between the first lateral face (21) and the second lateral face (22), wherein the guide rail (27) has, corresponding to the housing (2), a third lateral face (28) facing and spaced from a fourth lateral face (29) and the guide wall (30) extending longitudinally between the third lateral face (28) and the fourth lateral face (29), and wherein the third lateral face (28), the fourth lateral face (29) and the guide wall (30) of the guide rail (27) are respectively facing the first lateral face (21),the second lateral face (22) and the first longitudinal face (23) of the housing (2) in order to limit a movement of the guide rail (27) in all directions of the plane (P).,

7. A locking mechanism according to claim 6 wherein the first lateral face (21) of the housing and / or the second lateral face (22) of the housing do not have a common edge with the first longitudinal surface (23) of the housing, the first lateral face (21) of the housing, the second lateral face (22) of the housing and the first longitudinal surface (23) of the housing being obtained by a machining process and connected to each other by walls of raw material.

8. A locking mechanism according to any preceding claim wherein the housing has a first notch (25) and, wherein the guide rail (27) has a second notch (32), the first notch (25) of the housing and the second notch (32) of the guide rail being through and being intended to allow the passage of the actuator (37).

9. A locking mechanism according to any preceding claim wherein the guide rail (27) comprises a non-return stop (28) and / or an end-of-travel stop (29) preventing movement of the pushing device (38) beyond said guide rail (27).

10. Locking mechanism according to claim 9, wherein the non-return stop is provided by the third lateral face (28) of the guide rail (27) and / or the end-of-travel stop is provided by the fourth lateral face (29) of the guide rail (27).

11. A locking mechanism according to any preceding claim, wherein the positioning slot of the housing (2) further comprises at least one bottom face (47, 47') parallel to the plane (P), and correspondingly, the positioning wall (300) of the guide rail (27) further comprises at least one bottom face (31, 31') parallel to the plane P, the at least one bottom face (31, 31') being opposite the at least one bottom face (47, 47') so as to limit the movement of the guide rail (27) in a direction perpendicular to the plane (P).

12. A locking mechanism according to any preceding claim, wherein a fixing means fixes the guide rail (27) to the transmission housing (1), the fixing means blocking movement of the guide rail in a direction perpendicular to the plane (P).

13. A locking mechanism according to any preceding claim wherein the guide rail (27) is formed integrally from a folded strip of metal material, in particular from a steel sheet.

14. A transmission system comprising a shaft equipped with at least one locking recess (45) and a locking mechanism according to any one of claims 1 to 13.

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