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 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; - an actuator (37) which moves a thrust device (38) guided by a guide rail (27), in which the thrust device comprises a cam follower adapted to move on the cam surface; - a housing (2) formed in the transmission housing comprising a positioning slot in which a wall of the guide rail is inserted. (Abstract Figure: 8)

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 transmission 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 FR3128754, locking mechanisms comprising a 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 an actuator which moves a movable carriage which is guided in translation on the transmission casing by means of a guide rail. The movable carriage comprises a roller which cooperates with a cam surface of the pawl so that a translational movement of the movable carriage causes the pawl to pivot. The guide rail is a stamped sheet metal part comprising several folded walls allowing its positioning by fitting into a housing provided in the transmission casing.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 structure of the locking mechanism is of simple design, easy to assemble and sufficiently robust to withstand the significant mechanical stresses which may occur during the transition from the released position to the locking 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 which is difficult to manufacture; • the production of the surfaces of the guide rail housing in the housing 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 which 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 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.

[0008] An idea underlying the invention is a locking mechanism intended to lock a shaft of a vehicle 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 in rotation a shaft of a vehicle equipped with at least one locking recess, the locking mechanism comprising:

[0011] - a movable pawl comprising a locking finger, the movable pawl being pivotally mounted 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 thrust device, the thrust device comprising a cam follower adapted to move on the cam surface 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 pushing 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, positioning of the guide rail in a chosen direction of the plane is ensured very precisely because this positioning does not depend only and directly of two dimensions which are that of the positioning wall and that of the slot. In addition, the implementation of the slot can be carried out economically by the simple passage of a machining tool, and thus significantly reduces the quantity of way to machine in the housing.

[0017] According to an additional characteristic of the invention, the housing is formed from material in the transmission housing.

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

[0019] According to an additional characteristic of the invention, the pushing device is in the form of a mobile carriage comprising a first mobile roller capable of moving along the guide wall of the guide rail and a second mobile roller capable of moving on the cam surface of the mobile pawl.

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

[0021] According to an additional characteristic of the invention, the pushing device is in the form of a single-piece end piece, for example with a rounded or conical end, the single-piece end piece 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 pushing device is carried out with a small number of components and therefore a reduced cost.

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

[0024] According to an additional characteristic of the invention, the positioning wall and the guide wall form a single wall, the positioning wall comprising at least two protrusions extending substantially in a direction parallel to the movement of the pushing 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 characteristic allows several advantages: • the single wall gives the guide rail a simple shape to manufacture, without bending or complex geometry connection area 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 pushing 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 of smaller dimensions compared to those of the guide wall, for example the largest surface of a protrusion of the positioning wall is 10% to 30% smaller than the largest surface of the guide wall. These small protrusions make it possible to obtain, during the manufacture of the guide rail, a reduction in positioning and flatness defects of the positioning wall. These small protrusions also make it possible to limit the risk of the guide rail jamming during its assembly in the positioning slot of the housing.

[0027] According to an additional characteristic of the invention, the first positioning face of the housing and the second positioning face of the housing are parallel.

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

[0029] According to an additional characteristic of the invention, a width of the positioning slot, a thickness of the positioning wall and an operating clearance being 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, the ease of implementation is improved because it depends directly on the machining manufacturing tolerance of the slot and the thickness tolerance of the guide wall. As a result, the tolerance of the value of the operating clearance turns out to be reduced, which increases the accuracy of the positioning 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 to be the smallest distance existing between the first positioning face of the housing and the second positioning face of the housing.

[0032] According to an additional characteristic of the invention, the housing has a first lateral face opposite and distant from a second lateral face and a first longitudinal face situated between the first lateral face and the second face. lateral, in which the guide rail has 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 further allows the assembly and positioning of the guide rail in the housing of the casing in a simple and economical manner. 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 folding operation from a metal sheet.

[0035] According to an additional characteristic of the invention, an assembly clearance 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 clearance preferably being between 0.2 and 1 mm.

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

[0037] According to an additional characteristic of the invention, the guide rail is mounted tightly in the housing by a fitting connection

[0038] According to an additional characteristic of the invention, the guide rail is mounted tightly in the housing by the interposition of a prestressed elastic part between the guide rail and the housing.

[0039] According to an additional characteristic of the invention, the guide rail comprises two legs bent at an angle of 90 degrees relative to the guide wall, each bent leg forming a side wall which supports one of the two side faces of the guide rail.

[0040] According to an additional characteristic of the invention, the guide rail comprises a single tab bent at an angle of 90 degrees relative to the guide wall, the bent tab forming a side wall which supports the third side face of the guide rail, a cutting edge of the thickness of the guide wall forming the fourth side face of the guide rail.

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

[0042] According to an additional characteristic of the invention, the guide rail is flat, a first cutting edge of the thickness of the guide wall forming the third lateral face of the guide rail, a second cutting edge of the thickness of the guide wall forming the fourth lateral face of the guide rail.

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

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

[0045] According to an additional characteristic 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 1.5 mm and 3.5 mm; preferably between 2.5 and 3 mm.

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

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

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

[0049] According to an additional characteristic of the invention, the walls of the housing carrying 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 an additional characteristic of the invention, the walls of the housing carrying the first longitudinal face, the first lateral face and the second lateral face may have stiffeners oriented perpendicular to the first longitudinal face and / or to the first lateral face and / or to the second lateral face, the stiffeners being for example triangular in shape,

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

[0052] According to an additional characteristic of the invention, the casing is manufactured by a foundry process, in particular aluminum or magnesium foundry.

[0053] According to an additional characteristic 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 quantity of material to be machined. In the invention, raw material is understood to mean material that has not been machined. For example, the raw material may come from a foundry 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 an additional characteristic of the invention, the walls of the guide rail and / or the walls of the housing may comprise chamfers or radii 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 characteristic of the invention, the housing has a height of between 15 mm and 30 mm.

[0057] According to an additional characteristic 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 being intended to allow the passage of the actuator.

[0058] According to an additional characteristic 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 an additional characteristic 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 characteristic of the invention, the guide rail comprises a non-return stop and / or an end-of-travel stop preventing the movement of the pushing device beyond said guide rail.

[0061] Thanks to these characteristics, the pushing device is held in the housing.

[0062] According to an additional characteristic of the invention, the non-return stop is produced by the third lateral face of the guide rail and / or the end-of-travel stop is produced by the fourth lateral face of the guide rail.

[0063] According to an additional characteristic of the invention, the positioning slot of the housing further comprises at least one bottom face parallel to the plane and, correspondingly, the positioning wall of the guide rail further comprises at least one lower face parallel to the plane, the at least one lower face being opposite the 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 characteristic of the invention, a fixing means fixes the guide rail to the transmission casing, the fixing means blocking a movement of the guide rail in a direction perpendicular to the plane.

[0065] According to an additional characteristic of the invention, the fixing means is for example: a screw, a screw 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 an additional characteristic of the invention, the guide rail is formed in one piece from a folded strip of metallic material, in particular from a steel sheet.

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

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

[0069] According to an additional characteristic of the invention, the guide rail is manufactured from 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 previously.

[0072] According to an additional characteristic of the invention, the shaft comprises a wheel comprising the at least one locking recess. For example, the wheel is a ratchet wheel.

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

[0074] According to an additional characteristic 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 previously. Brief description of the figures

[0076] [Fig. 1] [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] [Fig.2] is a perspective view of the housing of [Fig.l].

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

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

[0080] [Fig.5] [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] [Fig.7] is a schematic side view of the housing portion and guide rail of [Fig.4].

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

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

[0085] [Fig. 10] [Fig. 10] is a perspective view of a housing according to a second embodiment.

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

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

[0088] 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 may also be combined or interchanged to provide other embodiments.

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

[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 casing 1 (partially shown) comprising a housing 2 of the locking mechanism of a vehicle according to a first embodiment.

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

[0093] The housing 2 is intended to house and position a guide rail, illustrated in particular in figures 3, 4 and 5. The housing 2 has, for example, a general “L” shape with rounded edges.

[0094] The housing 2 comprises a first lateral face 21 facing and distant from a second lateral face 22. The housing 2 further comprises longitudinally a first positioning face 23 facing 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, that is to say that 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 different pressure forces exerted on the guide rail 27 can be taken up by the faces of the housing 2 and therefore by the transmission casing 1.

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

[0098] In a similar manner 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 facing 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 may 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 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 comprise two bottom faces 47, 47' parallel to the plane P and, correspondingly, the two protrusions 300 and 300' of the guide rail 27 may comprise 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 of the order of 0.2 to 0.6 mm.

[0103] Furthermore, the first lateral face 21 of the housing 2 may comprise a first notch 25 intended to allow the passage of an actuator which is illustrated in FIGS. 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 comprise 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 FIGS. 8 and 9.

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

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

[0107] The guide rail may be manufactured for example from a strip of metal material which is on the one hand cut in order to form the second notch 32 then folded twice in the lengthwise direction in order to form said walls which compose it. The metal strip before folding may also comprise a notch intended to form the second notch 32 of the guide rail. The thickness of the metal strip is for example of the order of 3 mm.

[0108] Figures 8 and 9 show 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 comprise a movable pawl 34 located in the transmission housing 1.

[0110] 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.

[0111] 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.

[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 comprise a cam surface 36 located on a fifth lateral face of the movable pawl 34, towards the inside of the housing 2. The second end 72 may further comprise a locking finger 35 projecting towards the outside of the housing 2 from a sixth 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, shown in [Fig. 12]. The locking recess 45 is for example located on a ratchet wheel 44 which is capable of receiving said locking finger 35, as illustrated in [Fig. 12] and which is fixed in rotation with the transmission shaft 60 to be blocked 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 at the first end 71 of the movable pawl 34. The torsion spring 50 may comprise a first end portion 51 which bears against a bearing surface of the transmission casing and a second end portion 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. The locking mechanism may further comprise an actuator 37, shown partially in [Fig. 7], which is fixed to the transmission casing 1. The actuator 37 may comprise a rod 39 capable of moving in 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 pushing device 38 located in the housing 2.

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

[0116] In cases where the pushing device 38 is returned back by the pawl mobile 34 during dynamic phases, the pushing device 38 can come into abutment against the third lateral face 28 of the guide rail 27, which thus forms a stop anti-return for the thrust device 38. The thrust device 38, in this case, is sent against the movable pawl 34 by a return force exerted by a tension spring 40 which surrounds the rod 39 and which has a first end fixed to the body of the actuator and a second end fixed to the thrust device 38. This effect can occur for example during attempts at engagement at too high a speed. Beyond a threshold speed, for example between 3km / h and 5km / h, the movable pawl 34 rebounds to prevent engagement, the thrust device 38 is then returned to the stop.

[0117] In the embodiment of Figures 8 and 9, 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 the first 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.

[0118] 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 movable pawl 34 in the plane P.

[0119] To move the movable pawl 34 into the locking position, the rod 39 of the actuator 37 can be moved through the second notch 32 of the guide rail 27, thereby moving the pushing device 38 in a longitudinal direction. The pushing device 38 can be moved from the third lateral face 28 of the guide rail 27 toward the fourth lateral face 29 of the guide rail 27. The movement of the pushing 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 can have a slope, and the pushing device 38 can therefore exert, via its movement, pressure toward the cam surface 36 of the movable pawl 34.This pressure can cause a rotational movement of the second end of the movable pawl 34 towards a locking recess such 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] [Fig. 12] illustrates a transmission housing 1 comprising a ratchet wheel 44. The ratchet wheel 44 may have a plurality of recesses 45 regularly spaced from one another, all around the ratchet wheel 44. Each recess 45 of the plurality of recesses may have dimensions allowing the locking finger 35 of the movable pawl 34 to be received. [Fig. 12] further illustrates a shaft 60 of a vehicle which is blocked in rotation by the locking mechanism.

[0121] To move the locking mechanism from the locked position to the released position, the rod 39 can be moved so as to move the pushing device 38 towards the third lateral face 28 until it abuts 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 rotation of the transmission shaft 60.

[0122] Figures 10 to 11 illustrate a second embodiment of the housing 2 in 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 of [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 being for example obtained by a machining process and connected to each other by walls of raw foundry material.

[0123] In the embodiment of [Fig. 10], the different walls originating from the casing which carry 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 foundry process. These walls may comprise stiffeners (100, 100') oriented perpendicular to the first longitudinal face 23 and / or to the first lateral face 21 and / or to the second lateral face 22, the stiffeners being for example triangular in shape.

[0124] It is emphasized that all features, 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, can 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.

[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 cannot 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 one of the preceding claims, 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.

Images