Propulsion system provided with a locking device, such as a parking brake

Abstract

The invention relates to a propulsion system (1) for a mobility device comprising: - a casing (6) defining a motor space (7); - an electric motor (3) which is housed in the motor space (7), the electric motor (3) comprising a stator (22) which is provided inside the motor space (7) and a rotor (23) mounted to a primary shaft (2) so as to rotate therewith, the rotation of the primary shaft (2) being guided about an axis X relative to the casing (6) by means of a first bearing (24) and a second bearing (25) which are respectively arranged on either side of the rotor (23); - a locking gear (50) connected to the primary shaft (2) so as to rotate therewith, the locking gear (50) being suitable for and intended to co-operate with a locking mechanism (51) which is arranged so as to assume a locked state in which the locking mechanism (51) co-operates with the locking gear (50) in such a way as to prevent the rotation thereof about the axis X, the locking gear (50) being positioned between the first bearing (24) and the second bearing (25).

Description

Propulsion system equipped with an interlocking device, such as a parking brake |Technical field

[0001] The invention relates to the field of propulsion systems for a mobility device, such as a motor vehicle, equipped with a locking device.

[0002] The invention relates in particular to propulsion systems comprising an electric motor and a locking device, such as a parking brake, for locking the propulsion system so as to prevent the mobility device from rolling unintentionally. Such a propulsion system may also comprise a reduction device receiving the torque supplied by the rotor of the electric motor and a differential device which makes it possible to distribute the torque from the reduction device to two wheel shafts of an axle of the vehicle by allowing the two wheel shafts to rotate at different speeds. Technological background

[0003] Document EP3478992 discloses a propulsion system of the aforementioned type. The parking brake comprises a parking brake housing which is fixed to the casing of the electric motor, a locking shaft which is housed in the parking brake housing and is rotationally fixed to the rotor shaft, a locking wheel which is connected rotationally fixed to the locking shaft and a locking mechanism which comprises a blocking element movable between a released state and a locked state in which it cooperates with the locking wheel so as to block it from rotation, which immobilizes the propulsion system and thus prevents the motor vehicle from rolling away unintentionally.

[0004] The locking shaft is guided in rotation inside the parking brake housing by means of a dedicated rolling bearing. This rolling bearing is dimensioned to absorb significant radial forces generated by the locking element on the locking wheel and consequently on the locking shaft that carries it. Such a propulsion system is not entirely satisfactory. Indeed, the parking brake comprises a rolling bearing, a locking shaft and a housing that serve exclusively for the parking brake requirements, which increases the cost and complexity of the propulsion system. Summary

[0005] An idea underlying the invention is therefore to propose a propulsion system of the aforementioned type, that is to say comprising a locking device, such as a parking brake, which is less complex and less expensive.

[0006] To do this, according to a first aspect, the invention provides a propulsion system for a mobility device comprising: - a casing comprising an engine space; - an electric motor which is housed in the motor space, said electric motor comprising a stator fixed inside the motor space and a rotor mounted integral in rotation with a primary shaft, the primary shaft being guided, in rotation about an axis X, relative to the casing, by means of a plurality of bearings, the plurality of bearings comprising at least a first bearing and a second bearing which are respectively arranged axially on either side of the rotor; - a locking wheel which is integral in rotation with the primary shaft around the X axis, said locking wheel being capable and intended to cooperate with a locking mechanism which is arranged to take a locked state in which said locking mechanism cooperates with the locking wheel so as to block it in rotation around the X axis, said locking wheel being positioned axially between the first bearing and the second bearing.

[0007] Thus, the first and second bearings allow both the rotor and the locking wheel to be guided in rotation, which makes it possible to do without one or more dedicated bearings to take up the forces exerted on the locking wheel. The aforementioned propulsion system is therefore simpler and less expensive. In addition, the positioning of the locking wheel, between the first and second bearings, ensures a satisfactory distribution of the forces exerted on the locking wheel.

[0008] According to embodiments, such a propulsion system may comprise one or more of the following features.

[0009] According to one embodiment, no bearing of the plurality of bearings is arranged axially between the first bearing and the second bearing. Thus, the plurality of bearings may comprise only the first bearing and the second bearing or even one or more other additional bearings. In the case of one or more additional bearings, the first and second bearings are respectively the closest to the rotor on either side of the rotor. In other words, the guide bearing of the primary shaft closest to the first bearing, on the other side of the rotor, is the second bearing and the primary shaft guide bearing closest to the second bearing, on the other side of the rotor, is the first bearing.

[0010] According to one embodiment, the mobility device is a motor vehicle.

[0011] According to one embodiment, the locking wheel is formed in one piece with the primary shaft, in particular with the rotor shaft. This makes it possible to limit the number of components of the propulsion system and contributes in particular to simplifying its assembly.

[0012] According to another embodiment, the locking wheel is a part separate from the primary shaft which is mounted thereon and secured in rotation to it, for example by means of splines.

[0013] According to one embodiment, the locking wheel comprises a plurality of recesses, the propulsion system comprising a locking mechanism comprising a locking finger movable between a released position and a locked position in which said locking finger is capable of being housed in one of the recesses of the locking wheel so as to block it from rotating.

[0014] According to one embodiment, the recesses are provided on a periphery of said locking wheel.

[0015] According to one embodiment, the locking mechanism is arranged outside the engine space. This in particular avoids consequently increasing the size of the engine space in order to be able to accommodate the locking mechanism there.

[0016] According to one embodiment, the locking mechanism further comprises: - a pawl which is pivotally mounted on the housing and which includes the locking finger, said pawl comprising a cam surface; - a movable carriage which is guided in translation by means of a guide rail fixed to the housing, the movable carriage comprising a cam follower capable of moving on the cam surface of the pawl in order to pivot said pawl and thus move the locking finger between the released position and the locked position.

[0017] According to one embodiment, the cam follower is a roller.

[0018] According to one embodiment, the mobile carriage comprises a roller capable of rolling against a guide surface of the guide rail.

[0019] According to one embodiment, the locking mechanism is mounted in the transmission space.

[0020] The transmission space is defined by two parts of the housing which are fixed to each other.

[0021] According to one embodiment, the ratchet is pivotally mounted around a rod. According to one embodiment, the rod is mounted to bear on each of the two parts which define the transmission space.

[0022] According to one embodiment, the propulsion system further comprises an actuator which cooperates with the locking mechanism so as to move the locking finger between the released position and the locked position.

[0023] According to one embodiment, the actuator cooperates with a rod fixed to the mobile carriage.

[0024] According to one embodiment, the actuator is arranged outside the housing. This avoids consequently increasing the size of the housing to be able to house the actuator.

[0025] According to one embodiment, the propulsion system comprises a reduction device comprising an input wheel which is coaxial with the X axis and rotationally fixed to the primary shaft, the reduction device being housed in a transmission space of the casing.

[0026] According to one embodiment, the input wheel and the locking wheel are arranged axially on either side of the rotor. This architecture makes it possible in particular to free up space at the level of the reduction device.

[0027] According to another embodiment, the input wheel and the locking wheel are arranged axially on the same side of the rotor, the locking wheel being arranged axially between the rotor and the input wheel.

[0028] The primary shaft may be formed as a single piece. In other words, the primary shaft may be a rotor shaft extending axially beyond the engine space.

[0029] Alternatively, the primary shaft may comprise a plurality of coaxial shafts coupled to each other. For example, the primary shaft may comprise a rotor shaft coupled to an input shaft carrying the input wheel or on which the input wheel is directly formed.

[0030] According to one embodiment, the input wheel is a toothed wheel.

[0031] According to one embodiment, the input wheel may be located on a free end area of ​​the primary shaft. In other words, all the guide bearings guiding the primary shaft are located axially on the same side of the input wheel.

[0032] According to one embodiment, the primary shaft is guided by only two bearings, namely the first bearing and the second bearing. Thus, the guidance of the primary shaft is simplified.

[0033] According to one embodiment, the housing comprises a first and a second end wall, the first and the second end walls respectively comprising a first housing and a second housing, the first bearing and the second bearing being respectively housed in the first housing and in the second housing.

[0034] According to one embodiment, the first and second end walls define two ends of an engine compartment.

[0035] According to one embodiment, the first bearing and the second bearing are rolling bearings.

[0036] According to one embodiment, each of the first and second bearings comprises an inner ring, an outer ring and rolling bodies interposed between the inner ring and the outer ring.

[0037] According to one embodiment, the rolling bodies are chosen from balls, rollers and needles.

[0038] According to one embodiment, the first bearing and the second bearing are respectively fitted onto a first and a second internal bearing surfaces of the primary shaft, each of the first and second internal bearing surfaces being delimited in the direction of the other by a first and a second axial bearing surfaces of the primary shaft.

[0039] According to one embodiment, the first housing comprises a first external bearing surface and a first axial bearing surface of the casing, the first bearing being arranged radially between the first internal bearing surface and the first external bearing surface and axially between the first axial bearing surface of the primary shaft and the first axial bearing surface of the casing.

[0040] According to one embodiment, the second housing comprises a second external bearing surface and a second axial bearing surface of the casing, the second bearing being arranged radially between the second bearing surface internal and the second external bearing surface and axially between the second axial bearing surface of the primary shaft and the second axial bearing surface of the casing.

[0041] According to one embodiment, the primary shaft is guided only by two bearings, namely the first bearing and the second bearing.

[0042] According to one embodiment, if the primary shaft is guided by more than two bearings, the first and second bearings are the bearings closest to the rotor axially on either side of the rotor.

[0043] In other words, no other guide bearing is interposed between the first and second guide bearings.

[0044] According to one embodiment, the input wheel is a separate part from the primary shaft.

[0045] According to one embodiment, the input wheel is rotationally secured to the primary shaft by means of splines.

[0046] According to one embodiment, the input wheel bears, on the one hand, against a shoulder of the primary shaft and, on the other hand, against a circlip mounted in a groove of the primary shaft.

[0047] According to one embodiment, the locking wheel and the input wheel are arranged axially on either side of the second bearing.

[0048] According to one embodiment, the second end wall comprises an opening which is arranged opposite at least one recess of the locking wheel and which is capable of being crossed by a locking finger of the locking mechanism when said locking finger is in a locked position. This allows the locking mechanism to be positioned outside the engine space, and for example in a transmission space, while acting on a locking wheel supported by the bearings guiding the primary shaft in rotation.

[0049] According to one embodiment, the recesses are provided on a periphery of said locking wheel, the second end wall comprising a projecting portion which projects axially in a direction opposite the engine compartment and in which the second bearing is positioned, the locking wheel being housed in said projecting portion, the opening being provided in said projecting portion radially opposite the periphery of the locking wheel.

[0050] According to one embodiment, the housing comprises a transmission space separated from the engine space by the second wall which thus defines an engine compartment and a transmission compartment, the locking mechanism being housed in said transmission compartment. This allows the locking mechanism to be positioned outside the engine compartment, in a transmission compartment which allows both the locking mechanism and other elements of the transmission chain to be housed.

[0051] According to one embodiment, the housing comprises a transmission compartment, the second bearing contributing to delimiting the engine compartment and the transmission compartment.

[0052] According to one embodiment, the input wheel and the rotor are located axially on either side of the second bearing, or the locking wheel and the input wheel are located axially on either side of the second bearing.

[0053] According to one embodiment, the propulsion system comprises a differential drive device which is configured to distribute the torque of the reduction device to two wheel shafts of an axle of a vehicle.

[0054] According to one embodiment, the differential drive device is housed in the transmission space.

[0055] According to one embodiment, the reduction device comprises an intermediate shaft which is guided in rotation inside the transmission space along a Y axis, parallel to the X axis, the intermediate shaft being engaged with the input shaft via a first set of gears comprising the input wheel and engaged with the differential device via a second set of gears.

[0056] According to one embodiment, the differential device comprises a differential box which is guided in rotation about the Z axis, two satellite gears which are mounted in rotation on the differential box about an axis W perpendicular to the Z axis and two planetary gears which are movable in rotation about the X axis, are each engaged with the two satellite gears and are each intended to drive in rotation directly or indirectly a wheel shaft.

[0057] According to an alternative embodiment, the primary shaft is guided by the first and second bearings on its two end zones. These two end zones are housed in cavities in the casing.

[0058] The propulsion system is a cooling and / or lubrication type system shared between the transmission space and the engine space.

[0059] The invention also relates to an electric machine comprising a rotor shaft and a locking wheel rotatably coupled with the rotor shaft. Brief description of the figures

[0060] The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the accompanying drawings.

[0061] Figure 1 is a perspective representation of a propulsion system according to a first embodiment.

[0062] Figure 2 is a sectional view of the propulsion system of Figure 1.

[0063] Figure 3 is a detailed view of the locking device equipping the propulsion system of Figures 1 and 2.

[0064] Figure 4 is a perspective view of the arrangement of the locking mechanism in the transmission space of the propulsion system of Figures 1 to 3.

[0065] Figure 5 is a perspective view of one of the parts of the housing defining the transmission space and in which the locking mechanism is not shown.

[0066] Figure 6 is a sectional view of a propulsion system according to a second embodiment.

[0067] Figure 7 is a partial diagram of a propulsion system according to a third embodiment.

[0068] Figure 8 is a partial diagram of a propulsion system according to a fourth embodiment.

[0069] Figure 9 is a partial diagram of a propulsion system according to a fifth embodiment.

[0070] Figure 10 is a partial diagram of a propulsion system according to a sixth embodiment.

[0071] Figure 11 is a partial diagram of a propulsion system according to a seventh embodiment. Description of the embodiments

[0072] In the description and the claims, the terms "external" and "internal" as well as the orientations "axial" and "radial" will be used to designate, according to the definitions given in the description, elements of the propulsion system 1. By convention, the axis X of rotation of the primary shaft 2 defines the "axial" orientation. The terms "external" and "internal" are used to define the relative position of one element with respect to another, with reference to the axis X, an element close to the axis X is thus qualified as internal as opposed to an external element located radially on the periphery.

[0073] In relation to Figures 1 to 5, a propulsion system 1 is described according to a first embodiment. As illustrated in Figure 2, the propulsion system 1 comprises an electric motor 3, a reduction device 4 and a differential device 5. The propulsion system 1 is thus configured to generate a torque by means of the electric motor 3, increase it by means of the reduction device 4 and distribute it to the two wheel shafts, not shown, of an axle of the vehicle, allowing them to rotate at different speeds by means of the differential device 5.

[0074] According to an exemplary embodiment, such a propulsion system 1 is intended for a hybrid vehicle. Thus, the aforementioned propulsion module is, for example, capable of transmitting torque from the electric motor 3 to a rear or front axle of the vehicle while another propulsion system 1 comprising another motor, such as a heat engine, makes it possible to generate torque and transmit it between this other motor and the two wheel shafts of the other axle of the vehicle. According to another example, the vehicle is electric.

[0075] The propulsion system 1 comprises a casing 6 defining, on the one hand, a motor space in which the electric motor 3 is housed and, on the other hand, a transmission space in which the reduction device 4 and the differential device 5 are housed. In the embodiment illustrated in FIG. 2, the casing 6 comprises three parts, namely a first part 9, a second part 10 and a third part 11 which are fixed to each other. The second part 10 is arranged axially between the first part 9 and the third part 11.

[0076] The first part 9 and the second part 10 together define an engine compartment 7. In the embodiment shown, the first part 9 and the second part 10 each comprise an end wall 12, 13 and a cylindrical skirt 14, 15 extending parallel to the axis X from the periphery of the end wall 12, 13. The first part 9 and the second part 10 each comprise a fixing flange 16, 17 which fixes against the fixing flange 16, 17 of the other of the first and second parts 9, 10.

[0077] Similarly, the second part 10 and the third part 11 together define the transmission compartment 8. The second part 10 and the third part 11 are also fixed to each other by fixing flanges 18, 19. They each comprise a projecting boss. Each boss comprises an opening 20, 21 intended to receive one of the two wheel shafts of an axle of the motor vehicle.

[0078] The structure of the casing 6 is described above only by way of example. Also, according to other embodiments not shown, the casing 6 has another structure. By way of example, the casing 6 may in particular comprise four parts which define two by two the engine compartment 7 and the transmission compartment 8.

[0079] The electric motor 3 comprises a stator 22 which is fixed to the casing 6, inside the motor compartment 7, and a rotor 23 which is mounted to move in rotation along the axis X, inside the stator 22. To do this, the rotor 23 is mounted integral in rotation with a primary shaft 2. The primary shaft 2 is guided in rotation by means of a first bearing 24 and a second bearing 25, such as rolling bearings. The primary shaft 2 passes through the end wall 13 of the second part 10 and thus projects inside the transmission compartment 8.

[0080] Each of the first and second bearings 24, 25 comprises an inner ring, an outer ring and rolling bodies interposed between the inner ring and the outer ring. The rolling bodies are here balls but can also be rollers or needles in particular. Each of the first and second bearings can comprise one or more rows of rolling bodies. The inner ring of the first rolling bearing 24 and the inner ring of the second rolling bearing 25 are respectively fitted onto a first and a second inner bearing surfaces 26, 27 of the primary shaft 2. Each of the first and second inner bearing surfaces 26, 27 is delimited in the direction of the other of the first and second inner bearing surfaces by a shoulder 28, 29.The shoulders 28, 29 thus define a first and a second axial bearing surfaces against which the inner ring of the first bearing 24 and the inner ring of the second bearing 25 respectively come into abutment.

[0081] The first bearing 24 is housed inside a first cylindrical housing 30, formed in the first part 9 of the casing 6. The first housing 30 comprises a first external bearing surface 31 in which the external ring of the first bearing 24 is fitted as well as a shoulder 32 which borders the first external bearing surface towards the outside of the engine compartment 7. The shoulder 32 thus defines a first axial bearing surface of the casing 6 against which the external ring of the first bearing 24 abuts. In the embodiment shown, an elastic washer 69 is further arranged between the shoulder 32 and the external ring of the first bearing 24.

[0082] Thus, the first bearing 24 is arranged radially between the first external bearing surface 32 of the first housing 30 and the first internal bearing surface 26 of the primary shaft 2 and axially between the first axial bearing surface of the casing 6 and the first axial bearing surface of the primary shaft 2. The second bearing 25 is housed inside a second cylindrical housing 34, formed in the second part 10 of the casing 6. The second housing 34 comprises a second external bearing surface 35 in which the external ring of the second bearing 25 is fitted as well as a shoulder 36 which borders the second external bearing surface 35 towards the outside of the engine compartment 7. The shoulder 36 thus defines a second axial bearing surface of the casing 6 against which the external ring of the second bearing 25 abuts.Thus, the second bearing 25 is arranged radially between the second external bearing surface 35 of the second housing 34 and the second internal bearing surface 27 of the primary shaft 2 and axially between the second axial bearing surface of the casing 6 and the second axial bearing surface of the primary shaft 2.

[0083] Furthermore, the reduction device 4 comprises an intermediate shaft 37 which is mounted to rotate inside the transmission compartment 8 about an axis Y, parallel to the axis X. The intermediate shaft 37 is guided in rotation inside the casing 6 by means of two bearings 38, 39, such as rolling bearings, one of which is mounted in a housing provided on the second part 10 of the casing 6 and the other of which is mounted in a housing provided on the third part 11 of the casing 6. Furthermore, the reduction device 4 comprises an input wheel 40 which is integral in rotation with the primary shaft 2 and two toothed wheels 41, 42 integral in rotation with the intermediate shaft 37. The input wheel 40 is mounted on the portion of the primary shaft 2 which projects inside the transmission compartment 8.It is engaged with the larger input wheel 41 of the intermediate shaft 37 while the smaller input wheel 42 of the intermediate shaft 37 is engaged with. an input wheel 43 of the differential device 5. The reduction device 4 thus produces, from the electric motor 3 to the differential device 5, a transmission ratio less than 1, which makes it possible to deliver to the wheel shafts a torque greater than that delivered to the output of the electric motor 3. In the embodiment shown, the input wheel 40 is a separate part from the primary shaft 2 and is secured in rotation to the latter by means of splines. Furthermore, the input wheel 40 is, on the one hand, axially in abutment against the second bearing 25 (in particular its inner ring) of the primary shaft 2 and, on the other hand, in abutment against a circlip 58 mounted in a groove of the primary shaft 2, which makes it possible to axially fix the input wheel 40 on the primary shaft 2. As a variant, instead of bearing on the second bearing 25, the input wheel 43 can bear against a shoulder of the primary shaft 2.

[0084] Furthermore, the differential device 5 comprises a differential box 44 which is mounted to rotate inside the transmission casing 6 about an axis Z which is parallel to the axes X and Y. In Figure 2, the differential box 44 is guided in rotation by means of two bearings 45, 46, such as rolling bearings, one of which is housed in a housing of the second part 10 and the other of which is housed in a housing of the third part 11. The differential box 44 is coupled in rotation to the input wheel 42 of the differential device 5. The differential device 5 also comprises two satellite gears 47, only one of which is shown in Figure 2, which are mounted in rotation on the differential box 44, inside the latter, about an axis W, perpendicular to the axis Z, as well as two planetary gears 48, 49.The two planetary gears 48, 49 each comprise a bevel gear which meshes with a complementary bevel gear of the two satellite gears 47. In addition, the two planetary gears 48, 49 are rotatable about the Z axis. Each of the planetary gears 48, 49 comprises a splined hub intended to drive in rotation, directly or indirectly, one of the two wheel shafts, not shown, of an axle of the vehicle.

[0085] Furthermore, the propulsion system 1 comprises a locking device which makes it possible to block the propulsion system in order to prevent the motor vehicle from rolling involuntarily. The locking device comprises a locking wheel 50, visible in particular in FIGS. 2 and 3, a locking mechanism 51, visible in FIGS. 3 and 4, and an actuator 62, visible in FIGS. 1 and 3.

[0086] The locking wheel 50 is rotationally fixed to the primary shaft 2. In the embodiment shown, the locking wheel 50 is machined directly in the primary shaft 2, in particular the rotor shaft, as illustrated in particular in FIG. 2. In other words, the primary shaft 2 and the locking wheel 50 are formed in one piece. In another embodiment, as shown in FIG. 6, the locking wheel 50 is a separate part from the primary shaft 2. In such circumstances, it may in particular be fitted around the primary shaft 2, rotationally fixed thereto, for example by means of splines, and axially fixed thereto, between, on the one hand, a shoulder provided in the primary shaft 2 and, on the other hand, a circlip mounted in a groove in the primary shaft 2.

[0087] The locking wheel 50 is positioned axially between the first bearing 24 and the second bearing 25. Thus, the radial forces likely to be exerted on the locking wheel 50 by the locking mechanism 51 are taken up by the first and second bearings 24, 25 ensuring the rotational guidance of the rotor 23, which makes it possible to do without a dedicated bearing to take up the forces exerted on the locking wheel 50. In addition, the locking wheel 50 being positioned axially between the first and second bearings 24, 25, it is not positioned cantilevered relative to one of the two bearings 24, 25, which ensures better distribution of the forces. The locking wheel 50 and the input wheel 40 of the reduction device 4 are therefore arranged axially on either side of the second bearing 25.

[0088] As shown in Figure 3, the locking wheel 50 comprises a plurality of recesses 52, regularly spaced from each other, around the entire periphery of said locking wheel 50. In addition, the locking mechanism 51 is arranged to assume a locked state in which it cooperates with one of the recesses 52 of the locking wheel 50 so as to block it in rotation. To do this, the locking mechanism 51 comprises a pawl 53 which is pivotally mounted on the casing 6 about an axis U, parallel to the axis X. The pawl 53 is pivotally mounted about a rod 63 which is fixed to the casing 6. The pawl 53 is equipped with a locking finger 54. The pawl 53 is, moreover, movable between a locked position in which the locking finger 53 is adapted to be housed in one of the recesses 52 of the locking wheel 50 and a released position, shown in FIG. 3, in which said locking finger 54 is disengaged from the recesses 52 of the locking wheel 50. The locking mechanism 51 comprises also a return means, here a torsion spring 55, which allows the pawl 53 to be returned to the released position.

[0089] Furthermore, the locking mechanism 51 comprises a movable carriage 56 which is guided in translation on the casing 6 by means of a guide rail 57. The movable carriage 56 comprises a first roller 59 which rolls against a guide surface of the guide rail 57 and a second roller 60 which cooperates with a cam surface of the pawl 53. The cam surface of the pawl 53 is configured such that the translational movement of the movable carriage 56 causes the pawl 53 to pivot between the released position and the locked position. The movable carriage 56 is fixed to the end of a rod 61 which is moved in translation by an actuator 62. Advantageously, the actuator 62 is arranged outside the casing 6. Also, the casing 6 comprises an orifice which allows a shaft of the actuator 62 to be secured to the rod 61 through the casing 6.

[0090] In the embodiment shown, as illustrated in Figure 4, the locking mechanism 51 is housed in the transmission compartment 8. This has the effect of simplifying the mounting of the locking mechanism 51 since the rod 63 on which the pawl 53 is pivotally mounted can in particular be mounted to bear on the one hand, on the second part 10 and, on the other hand, on the third part 11 of the casing 6. To do this, according to one embodiment, the two ends of the rod 63 are respectively fitted into a housing of the second part 10 and of the third part 11 of the casing 6. In addition, the transmission compartment 8 having a larger radial dimension than the engine compartment 7, it has sufficient dimensions to house the locking mechanism 51 therein.In order to allow the locking mechanism 51, arranged in the transmission compartment 8, to act on the locking wheel 50 which is arranged in the engine compartment 7, the end wall 13 delimiting the engine compartment 7 and the transmission compartment 8 comprises a projecting portion 64 which projects towards the transmission compartment 8 and in which the primary shaft 2 passes. The locking wheel 50 is also housed inside this projecting portion 64. This projecting portion 64 comprises an axially oriented skirt 65 which extends around the primary shaft 2. The projecting portion 64 comprises an opening 66, notably visible in FIG. 5, which is arranged radially opposite the locking wheel 50. As shown in FIG. 4, the locking finger 54 of the pawl 53 passes through said opening 66 and is thus able to cooperate with the locking wheel 50. lock 50.

[0091] Furthermore, in the embodiment of Figure 4, the locking mechanism 51 is fixed to the second part 10 of the casing 6. Thus, the guide rail 57 is fixed to the second part 2 and the latter also comprises an orifice 67, visible in Figures 4 and 5, through which a shaft of the actuator 62 passes. Thus, in this embodiment, as shown in Figure 1, the actuator 62 is positioned outside the casing 6 and positioned relative to the transmission compartment 8 on the same side as the engine compartment 7. Also, the actuator 62 is positioned radially outside the engine compartment 7.

[0092] Figure 6 illustrates a propulsion system 1 according to a second embodiment. This embodiment differs mainly from that described above in relation to Figures 1 to 5 in that the locking mechanism 51 is not fixed on the second part 10 of the casing 6 but on the third part 11. In this case, the guide rail 57 is fixed on the third part of the casing 6 and the latter comprises an orifice, not shown in Figure 6, through which a shaft of the actuator 62 passes. In particular, as illustrated in Figure 6, the guide rail 57 is fixed inside a housing of the third part 11 which is defined by walls, one of which is referenced 68 in Figure 6, projecting from the third part 11 towards the second part 10 of the casing 6.

[0093] In this embodiment, as shown in Figure 6, the actuator 62 is positioned outside the housing 6 and positioned relative to the transmission compartment 8 on the side opposite the engine compartment 7.

[0094] According to an alternative embodiment, the locking wheel 50 can be arranged in a first plane and the pawl 50 can pivot in a second plane distinct from the first plane, the second plane being in particular not parallel to the first plane, for example substantially perpendicular to the first plane.

[0095] Figure 7 shows a third embodiment. The housing comprises at least three parts. As in the two previous embodiments, the housing comprises an engine compartment and a transmission compartment. These two compartments are separated by a second end wall inside which the second bearing 25 is mounted.

[0096] On the other hand, this third embodiment differs from the two previous ones in that the locking wheel 50 is arranged axially, relative to the rotor, on the other side of the input wheel 40. In other words, the locking wheel 50 is located axially between the first bearing 24 and the rotor. The second bearing 25 is again arranged axially between the rotor and the input wheel 40.

[0097] Figure 8 shows a fourth embodiment. Here, the casing has a common space for the electric motor and the reduction device. In other words, the motor space and the transmission space are not truly separated into compartments. The first bearing 24 and the second bearing 25 are arranged axially on either side of the rotor, the locking wheel 50 and the input wheel 40. The primary shaft is guided by the first and second bearings 24, 25 on its two end zones. The second bearing 25 is housed in a cavity of the casing. The locking wheel 50 is arranged axially between the input wheel 40 and the rotor.

[0098] In Figure 9 a fifth embodiment is shown diagrammatically in which the casing comprises a common space for the electric motor and the reduction device. The first bearing and the second bearing are arranged axially on either side of the rotor, the locking wheel 50 and the input wheel 40. The primary shaft is guided by the first and second bearings 24, 25 on its two end zones. The locking wheel 50 is arranged axially, relative to the rotor, on the other side of the input wheel 40. In other words, the locking wheel 50 is located axially between the first bearing 24 and the rotor.

[0099] A sixth embodiment is shown diagrammatically in Figure 10. In this embodiment, the primary shaft comprises a rotor shaft 70 and an input shaft 71 coupled to each other. Furthermore, the primary shaft is guided in rotation by a third bearing in addition to the first bearing 24 and the second bearing 25. In such a case, the input shaft 71 which carries the input wheel 40 is supported on the casing on either side of the input wheel 40 by the second bearing 25 and the third bearing 71 while the rotor shaft 71 is supported on the casing on the other side of the rotor by means of the first bearing 24. A first end of the rotor shaft is guided in rotation in the first bearing and the second end of the rotor shaft opposite the first end is coupled to the input shaft inside a coupling sleeve formed at the end of the input shaft. The coupling sleeve is guided in rotation inside the second bearing 25.

[0100] According to a variant not shown, the rotor shaft 71 is supported on the casing on either side of the rotor by first bearing 24 and second bearing 25 while the input shaft is supported on the casing by a third bearing on the other side of the input wheel. A first end of the input shaft is guided in rotation in the third bearing and the second end of the input shaft opposite the first end is coupled inside a coupling sleeve formed at Y1 the end of the rotor shaft. The coupling sleeve being guided in rotation inside the second bearing 25.

[0101] In Figure 10, the locking wheel 50 is arranged axially between the rotor and the second bearing 25.

[0102] The embodiment shown in Figure 11 differs from that of Figure 10 only in that the locking wheel is arranged axially between the rotor and the first bearing 24.

[0103] Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0104] In particular, although in the embodiments described above, the locking mechanism 51 is housed in the transmission compartment 8, it can also, according to other embodiments not shown, be housed, in whole or in part, in the engine compartment 7.

[0105] The use of the verb "comprise", "comprise" or "include" and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

[0106] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims

1. Propulsion system (1) for a mobility device comprising: - a casing (6) comprising an engine space; - an electric motor (3) which is housed in the motor space, said electric motor (3) comprising a stator (22) fixed inside the motor space and a rotor (23) mounted integral in rotation with a primary shaft (2), the primary shaft (2) being guided, in rotation about an axis X, relative to the casing (6), by means of a plurality of bearings, the plurality of bearings comprising at least a first bearing (24) and a second bearing (25), the first bearing (24) and the second bearing (25) being respectively arranged axially on either side of the rotor (23), no bearing of the plurality of bearings being arranged axially between the first bearing (24) and the second bearing (25); - a locking wheel (50) which is rotationally integral with the primary shaft (2) around the axis X, said locking wheel (50) being capable and intended to cooperate with a locking mechanism (51) which is arranged to take a locked state in which said locking mechanism (51) cooperates with the locking wheel (50) so as to block it in rotation around the axis X, said locking wheel (50) being positioned axially between the first bearing (24) and the second bearing (25).

2. Propulsion system (1) according to claim 1, wherein the locking wheel (50) is formed in one piece with the primary shaft (2).

3. Propulsion system (1) according to claim 1 or 2, wherein the locking wheel (50) comprises a plurality of recesses (52), the propulsion system comprising a locking mechanism (51) comprising a locking finger (54) movable between a released position and a locked position in which said locking finger (54) is adapted to be housed in one of the recesses (52) of the locking wheel (50) so as to block it in rotation.

4. A propulsion system (1) according to claim 3, wherein the locking mechanism (51) further comprises: - a pawl (53) which is pivotally mounted on the housing (6) and which includes the locking finger (54), said pawl (53) comprising a cam surface; - a movable carriage (56) which is guided in translation by means of a guide rail (57) fixed to the casing (6), the movable carriage (56) comprising a cam follower (59) capable of moving on the cam surface of the pawl (53) in order to pivot said pawl (53) and thus move the locking finger (54) between the released position and the locked position.

5. A propulsion system according to claim 3 or 4, further comprising an actuator (62) which cooperates with the locking mechanism (51) so as to move the locking finger (54) between the released position and the locked position.

6. A propulsion system according to claim 5, wherein the actuator (62) is arranged outside the casing (6).

7. Propulsion system according to one of claims 1 to 6, in which the propulsion system comprises a reduction device (4) comprising an input wheel (40) which is coaxial with the X axis and integral in rotation with the primary shaft (2), the reduction device being housed in a transmission space of the casing.

8. A propulsion system according to claim 7, wherein the input wheel (40) and the locking wheel (50) are arranged axially on either side of the rotor (23).

9. A propulsion system according to claim 7, wherein the input wheel (40) and the locking wheel (50) are arranged axially on the same side of the rotor (23), the locking wheel (50) being arranged axially between the rotor and the input wheel (40).

10. Propulsion system according to one of claims 1 to 9, in which the primary shaft (2) is guided only by two bearings, namely the first bearing (24) and the second bearing (25).

11. A propulsion system (1) according to any one of claims 1 to 10, wherein the casing (6) comprises a first and a second end wall (12, 13), the first and the second end wall (12, 13) respectively comprising a first housing (30) and a second housing (34), the first bearing (24) and the second bearing (25) being respectively housed in the first housing (30) and in the second housing (34).

12. Propulsion system according to claim 11 taken in combination with at least one of claims 7 and 9, in which the primary shaft (2) passes through the second end wall (13), the locking wheel (50) and the input wheel (40) being arranged axially on the same side of the rotor and axially on either side of the second end wall (13) and / or the second bearing (25).

13. A propulsion system according to claim 11 or 12, wherein the second end wall (13) comprises an opening (66) which is arranged opposite at least one recess (52) of the locking wheel (50) and which is capable of being passed through by a locking finger (54) of the locking mechanism (51) when said locking finger (54) is in a locked position.

14. A propulsion system according to claim 13, wherein the recesses (52) are provided on a periphery of said locking wheel (50), the second end wall (13) comprising a projecting portion (64) which projects axially in a direction opposite the engine compartment (7) and in which the second bearing (25) is positioned, the locking wheel (50) being housed in said projecting portion (64), the opening (66) being provided in said projecting portion (64) radially opposite the periphery of the locking wheel (50).

Images