Transmission system with coupling device

Abstract

The invention relates to a transmission system (1) for a motor vehicle, comprising: a first element (4) and a second element (5) which are rotationally movable relative to one another about an axis X; a coupling device (6) which comprises: a first coupling part (18) which is rotationally locked by the first element (4) and which is movable relative to the first element (4) between a coupled position and a decoupled position; a disc (36) including a fixing area axially fixed to the first coupling part (18), the disc (36) comprising at least one elastic return part (41) configured to elastically return the first coupling part (18) to the decoupled position; and a sensor (35) arranged facing an annular portion of the disc (36).

Description

[Technical field]

[0001] The invention relates to the field of vehicle drivetrains.

[0002] It more particularly relates to a transmission system comprising a first element intended to be driven by a motor, a second element intended to drive at least one wheel shaft of a vehicle, and a coupling device capable of selectively coupling the first element to the second element.

[0003] The invention particularly relates to a differential transmission system for transmitting and distributing torque from a motor to two wheel shafts of a vehicle axle. [Background technology]

[0004] Document US2015114786 discloses a differential transmission system. The transmission system comprises a differential housing, which is rotatably movable about an axis A and is equipped with a gear driven by a motor of a vehicle. In the housing, a carrier ring is accommodated which is rotationally guided in the housing, two planet gears mounted to rotate on the carrier ring about an axis B perpendicular to the axis A, and two sun gears each meshing with the two planet gears, each locked to rotate by a wheel shaft. Furthermore, the transmission system includes a coupling device which allows the coupling of the housing of the transmission system to the carrier ring to enable the transmission and distribution of torque from the engine to the two wheel shafts of the shaft, and the decoupling of them to interrupt the transmission torque between the motor and the wheel shafts.

[0005] The coupling device is a dog clutch device. It comprises a first coupling part having an annular part arranged on the outside of the housing and a protruding element extending from the annular part and passing through an orifice formed in the housing, which allows the first coupling part and the housing to be rotationally fixed. The protruding element comprises teeth intended to cooperate with complementary grooves formed in the carrier ring. The first coupling part is axially movable relative to the housing between a decoupled position and a coupled position in which the teeth of the first coupling part engage with the grooves of the carrier ring.

[0006] The electromagnetic actuator can exert an axial force on the first coupling portion to move it from the disengaged position to the engaged position. The transmission system further includes an annular target axially secured to the annular portion of the first coupling portion. The annular target is disposed axially opposite a sensor, such as a Hall effect sensor, that provides a signal representative of the axial distance between the sensor and the annular target.

[0007] The transmission system further comprises an elastic washer arranged axially between the annular target and the housing, the function of which is in particular to exert a return force on the first connection so as to return it to its separated position when the electromagnetic actuator no longer exerts a force on the first connection.

[0008] Such a transmission system is not entirely satisfactory.

[0009] In particular, the coupling device of a transmission system has many different parts, in particular to ensure the target and return functions of the coupling device in its disconnected position, which increases its complexity, its cost and / or its bulk. Summary of the Invention

[0010] The idea behind the invention is to propose a transmission system equipped with coupling devices, sensors and targets capable of emitting signals representative of the state of the coupling devices; this transmission system is simpler and / or less bulky.

[0011] According to one embodiment, the invention provides a transmission system for a motor vehicle comprising: - a first element and a second element movable in rotation relative to each other about an axis X, one of the first and second elements being intended to be driven by a motor and the other of the first and second elements being intended to drive at least one wheel shaft of a motorized vehicle; - Coupling device including: - a first connecting portion that is rotationally locked to the first element and a second connecting portion that is rotationally locked by the second element, the first connecting portion being movable relative to the first element between a connected position in which the first connecting portion is connected to the second connecting portion for transmitting torque between the first element and the second element, and a decoupled position in which the first connecting portion and the second connecting portion are decoupled from each other; - a disk including a fixing area axially fixed to the first connecting part, the disk comprising an annular portion forming a target and at least one elastic return portion configured to elastically deform during movement of the first connecting part from the separated position to the connected position and to exert a return force capable of elastically returning the first connecting part to the separated position.

[0012] The disk therefore has a double function: on the one hand, it forms a target whose position can be detected by a sensor so as to emit a signal indicating the position of the first part of the coupling device, and on the other hand, it ensures that the first part is returned to its decoupling position, which makes it possible to reduce the cost, complexity and bulk of such a transmission system.

[0013] According to various embodiments, such a transmission system may have one or more of the following features:

[0014] According to one embodiment, the transmission system comprises a sensor arranged facing an annular portion of the disk and configured to emit a signal representative of the distance between the annular portion forming the target and the sensor.

[0015] According to one embodiment, the sensor is arranged axially facing the annular portion of the disk.

[0016] According to one embodiment, during the movement of the first connecting part from the decoupled position to the coupled position, the elastic return is elastically pressured between a bearing area and a fixed area of ​​the transmission system, preferably said bearing area being axially fixed relative to the second connecting part.

[0017] According to one embodiment, the disk is made of spring steel, such as XC70 steel, advantageously prehardened. According to one embodiment, the disk has a thickness of 0.4 to 1.2 mm, for example of the order of 0.8 mm. According to one embodiment, the disk is made of stainless steel, a non-magnetic metal, which also limits unwanted leakage of magnetic flux.

[0018] According to one embodiment, the disc comprises a plurality of resilient return portions, each of which comprises a resilient blade that is bearable against a bearing area of ​​the transmission system, the resilient blade thus being subjected to an increasing bending force during movement of the first coupling part from the decoupled position to the coupled position.

[0019] According to one embodiment, the bearing region is axially fixed relative to the second connection part.

[0020] According to one embodiment, each of the resilient blades has a free end. Preferably, said resilient blades rest against a bearing area of ​​the transmission system via their ends.

[0021] According to one embodiment, each resilient blade is formed in a window formed in the disk.

[0022] According to one embodiment, the elastic blades are regularly distributed around the axis X so as not to create imbalances.

[0023] According to one embodiment, the coupling device comprises at least two elastic blades, preferably four elastic blades, regularly distributed around the axis X and pairwise symmetrical with respect to the axis X.

[0024] According to one embodiment, the elastic blade is located radially inside the annulus forming the target, which makes it possible to limit the radial bulk of the disk.

[0025] According to one embodiment, each resilient blade extends in a direction having a circumferential component about axis X. This makes it possible to obtain a greater length of the resilient blade for a given radial bulk, and therefore a less stiff resilient blade.

[0026] According to one embodiment, the disk and the elastic blade are dimensioned to generate a stiffness K1 against the axial movement of the first connecting part from the separated position to the connected position, which is between 5 and 50 N / mm.

[0027] According to one embodiment, the first element comprises a housing in which the second connecting portion is accommodated, and the first connecting portion comprises an inner portion accommodated inside the housing, an outer portion arranged outside the housing, and a plurality of connecting portions axially connecting the inner portion and the outer portion of the first connecting portion, each connecting portion passing through a corresponding through opening formed in the housing.

[0028] According to one embodiment, one of the inner and outer parts of the first connecting portion is annular and the other is provided with axially extending lugs at a continuation of the connecting portion.

[0029] According to one embodiment, the disk is arranged outside the housing and fixed to the outer part of the first connecting part, and each bearing area is located on the housing.

[0030] According to one embodiment, the housing comprises studs projecting axially towards the outside of the housing in the direction of the disks, each stud having one end forming one of the bearing areas, which makes it possible to avoid bending the elastic blades during manufacture of the disks.

[0031] According to one embodiment, when the first connecting portion is in the detached position, the resilient blade extends substantially in the plane of the annular portion of the target forming disk.

[0032] According to one embodiment, the stud has an axial dimension equal to or greater than the movement of the first coupling portion between the coupled position and the decoupled position.

[0033] According to one embodiment, the first element is a differential housing.

[0034] According to one embodiment, the second element comprises a carrier ring guided to rotate about axis X inside the housing, two planetary gears mounted to rotate on the carrier ring about axis Z perpendicular to axis X, and two sun gears movable to rotate about axis X and intended to be engaged respectively with the two planetary gears and each locked in rotation by the wheel shafts. The transmission system thus forms a differential enabling the wheel shafts to rotate at different speeds.

[0035] According to one embodiment, the two planetary gears each include bevel gear teeth that mesh with complementary bevel gear teeth of the two sun gears.

[0036] According to one embodiment, the second coupling part of the coupling device is locked for rotation with the carrier ring about the axis X. Thus, when the coupling device is in the coupled position, the transmission system distributes the torque coming from the engine towards the two wheel shafts. Conversely, in the uncoupled position of the coupling device, the transmission of torque between the housing and the carrier ring is interrupted.

[0037] According to one embodiment, the second connecting part of the connecting device is integrally formed with the carrier ring.

[0038] According to another embodiment, the second coupling part is locked in rotation by one of the sun gears. In such an embodiment, when the latter is in the coupling position, torque is transmitted between the first and second elements via the gears, but the differential function is prevented by the coupling device, which prevents the wheel shafts from rotating at different speeds.

[0039] According to one embodiment, the disk comprises a number of fastening tabs secured to the first connecting portion.

[0040] According to one embodiment, each of the fixing tabs comprises a proximal end connected to the annular portion forming the target and a free end fixed to the first connecting portion.

[0041] According to one embodiment, each locking tab is formed in a window formed in the disk.

[0042] According to one embodiment, the locking tabs extend radially. Preferably, the locking tabs extend radially inwardly from a radially outer edge of the window.

[0043] According to one embodiment, the fixing tabs are regularly distributed around the axis X so as not to create imbalances.

[0044] According to one embodiment, the coupling device comprises at least two fastening tabs, preferably four fastening tabs, regularly distributed around the axis X and symmetrical in pairs with respect to the axis X.

[0045] According to one embodiment, the fixing tabs are located radially inside the annular portion forming the target, which makes it possible to limit the radial bulk of the disk.

[0046] According to one embodiment, the fixing tab is fixed to the outer side of the first connecting part, in particular to its lug.

[0047] According to one embodiment, the outer side of the first connecting portion comprises an axially extending lug at the continuation of the connection portion, the lug passing through a window through which the fixing tab extends.

[0048] Preferably, each fixing tab is circumferentially located between two resilient blades. Preferably, there is a circle about axis X that intersects all the resilient blades and all the fixing tabs.

[0049] According to one embodiment, the free end of each fastening tab fits into a groove formed in the first connecting part, in particular in its lug. The groove may be radially hollowed out.

[0050] According to another embodiment, the free end of each fixing tab is fixed to the first connecting part, in particular to one of its lugs, by means of a fixing member, such as a screw.

[0051] According to one embodiment, the coupling device further comprises an actuator including a casing intended to be fixed to the chassis of the vehicle and a piston axially movable relative to the casing between a retracted position and a deployed position, the piston being in contact against an actuating area of ​​the disc such that movement of the piston from the retracted position to the deployed position causes movement of the first coupling part of the coupling device from the disengaged position to the engaged position. The disc thus also makes it possible to transmit actuating forces between the actuator and the first coupling part, which makes it possible to further reduce the cost, complexity and bulk of the transmission system.

[0052] According to one embodiment, the actuator comprises an electromagnet defining a housing within which a piston is axially movable between a retracted position and a deployed position, the piston comprising an annular body made from a ferromagnetic material. Such an electromagnetic actuator is particularly advantageous in that it exhibits excellent responsiveness.

[0053] According to one embodiment, the actuator comprises a paramagnetic end piece, fixed to the body of the piston and cooperating with an active area of ​​the disk, which prevents unwanted leakage of magnetic flux.

[0054] According to one embodiment, the actuator comprises a magnetic cap against which the body of the piston contacts when the piston is in the deployed position, thus holding the piston in the deployed position, which allows the electromagnet to be switched off.

[0055] According to one embodiment, the magnetic cap includes a shoulder against which a shoulder of the body of the piston contacts when the piston is in the deployed position.

[0056] According to one embodiment, the disc is capable of elastically deforming between its fixed and actuated regions during movement of the actuator piston from the retracted position to the deployed position, thus also allowing for compensation of manufacturing tolerances of the coupling device.

[0057] According to one embodiment, the working area of ​​the disk is separated from the contact area of ​​the first connecting part by an axial clearance dimensioned such that the disk deforms during movement of the actuator piston from a retracted position to a deployed position to compensate for axial manufacturing tolerances of the connecting device such that the working area of ​​the disk comes into contact against the contact area of ​​the first connecting part when said axial manufacturing tolerances of the connecting device are compensated.

[0058] According to one embodiment, the axial clearance is between 0.2 and 1.5 mm.

[0059] According to one embodiment, the disc is dimensioned to generate a stiffness K2 opposing the axial approach of the piston towards the first connecting part of between 50 and 500 N / mm.

[0060] The stiffness K2 is greater than the stiffness K1. Advantageously, the stiffness K2 is between 4*K1 and 20*K1, for example 10*K1.

[0061] According to one embodiment, the active area of ​​the disk is the inner annular portion, which makes it possible to limit the radial bulk of the coupling device.

[0062] According to one embodiment, the inner annular portion is provided with oil passage grooves, the presence of oil being able to reduce possible friction between the piston and the disc.

[0063] According to one embodiment, the coupling device is a dog clutch device, one of the first and second coupling parts having teeth and the other having corresponding grooves in which the teeth engage when the first coupling part is in the coupled position.

[0064] According to one embodiment, the coupling device is a disconnecting device capable of selectively disconnecting the transmission of torque between the first element and the second element.

[0065] According to an embodiment, the invention also relates to the motor vehicle and transmission system described above.

[0066] According to one embodiment, the motor vehicle comprises an electric machine, and a first element of the transmission system is drivable by the electric machine.

[0067] The electric machine and transmission system may be integrated into an electric shaft.

[0068] According to a second aspect, the invention also provides a transmission system for a motor vehicle comprising: - a first element and a second element movable in rotation relative to each other about an axis X, one of the first and second elements intended to be driven by a motor and the other of the first and second elements intended to drive at least one wheel shaft of a motorized vehicle; and - A coupling device comprising: - a first connecting part that is rotationally locked by the first element and a second connecting part that is rotationally locked by the second element, the first connecting part being movable relative to the first element between a connected position and a disconnected position, in which the first connecting part is connected to the second connecting part to transmit torque between the first element and the second element, and in which the first connecting part and the second connecting part are disconnected from each other; a transmission member having a fixing region axially fixed to the first connecting portion; - an actuator comprising a casing intended to be fixed to a chassis of a vehicle and a piston axially movable relative to the casing between a retracted position and a deployed position, the piston being in contact against an actuating area of ​​a transmission member such that movement of the piston from the retracted position to the deployed position causes movement of a first coupling part of a coupling device from a decoupled position to a coupled position, the transmission member being elastically deformable between the fixed area and the actuating area of ​​the transmission member during movement of the piston of the actuator from the retracted position to the deployed position.

[0069] The transmission member therefore makes it possible to compensate for manufacturing tolerances of the coupling device.

[0070] Preferably the transmission member is a disk.The outer portion may form a sensor target.

[0071] This second aspect of the invention may include one or more of the features mentioned in relation to the first aspect of the invention.

[0072] According to a third aspect, the invention also provides a transmission system for a motor vehicle comprising: - a first element and a second element movable in rotation relative to each other about an axis X, one of the first and second elements intended to be driven by a motor and the other of the first and second elements intended to drive at least one wheel shaft of a motorized vehicle; and - A coupling device comprising: - a first connecting part that is rotationally locked by the first element and a second connecting part that is rotationally locked by the second element, the first connecting part being movable relative to the first element between a connected position and a disconnected position, in which the first connecting part is connected to the second connecting part to transmit torque between the first element and the second element, and in which the first connecting part and the second connecting part are disconnected from each other; - a disk comprising a fastening area axially fixed to the first connecting part and an annular portion forming the target; - an actuator comprising a casing intended to be fixed to a chassis of a vehicle and a piston axially movable relative to the casing between a retracted position and a deployed position, the piston contacting an active area of ​​a disc such that movement of the piston from the retracted position to the deployed position causes movement of a first coupling part of a coupling device from a decoupled position to a coupled position.

[0073] The disc therefore has a dual function: on the one hand, it forms a target whose position is detected by a sensor so as to emit a signal indicative of the position of the first part of the coupling device, and on the other hand, it transmits the actuating force between the actuator piston and the first coupling part, which makes it possible to reduce the cost, complexity and bulk of the transmission system.

[0074] This third aspect of the invention may include one or more of the features mentioned in relation to the first aspect of the invention.

[0075] In particular, the disc is capable of elastically deforming between a fixed area and an actuated area of ​​the disc during movement of the actuator piston from a retracted position to a deployed position.

[0076] According to a fourth aspect, the invention also provides a transmission system for a motor vehicle comprising: - a first element and a second element movable in rotation relative to each other about an axis X, one of the first and second elements intended to be driven by a motor and the other of the first and second elements intended to drive at least one wheel shaft of a motorized vehicle; and - A coupling device comprising: - a first connecting part that is rotationally locked by the first element and a second connecting part that is rotationally locked by the second element, the first connecting part being movable relative to the first element between a connected position and a disconnected position, in which the first connecting part is connected to the second connecting part to transmit torque between the first element and the second element, and in which the first connecting part and the second connecting part are disconnected from each other; - a transmission member including a fixing region axially fixed to the first connecting portion, the transmission member comprising an elastic return portion configured to elastically deform during movement of the first connecting portion from the separated position to the connected position and to exert a return force capable of elastically returning the first connecting portion to the separated position; - an actuator comprising a casing intended to be fixed to a chassis of a vehicle and a piston axially movable relative to the casing between a retracted position and a deployed position, the piston being in contact against an actuating area of ​​a transmission member such that movement of the piston from the retracted position to the deployed position results in movement of a first coupling part of a coupling device from a disengaged position to a coupled position.

[0077] The transmission member therefore has a dual function, i.e. on the one hand, it ensures the return of the first connecting part to its separated position and, on the other hand, it transmits the actuating force between the actuator piston and the first connecting part, which makes it possible to reduce the cost, complexity and bulk of the transmission.

[0078] This fourth aspect of the invention may include one or more of the features mentioned in relation to the first aspect of the invention.

[0079] In particular, the transmission member is capable of elastically deforming between the fixed area and the working area of ​​the disk during the movement of the actuator piston from the retracted position to the deployed position, so that two different elastic stiffnesses ensure, on the one hand, the elastic return of the first connecting part and, on the other hand, the compensation of the dimensional chain tolerances.

[0080] Preferably, the transmission member is a disk. An outer portion of the disk may form the sensor target. [Brief description of the drawings]

[0081] The invention will be better understood and further objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments thereof, given by way of non-limiting illustration only, with reference to the accompanying drawings, in which: [Figure 1] FIG. 1 is a general cross-sectional view of a transmission system equipped with a coupling device according to a first embodiment. [Diagram 2]FIG. 2 is a cross-sectional cutaway view of the transmission system of FIG. 1 with the coupling device in a disengaged position. [Diagram 3] FIG. 3 is a cross-sectional view similar to that of FIG. 2, with the coupling device in the coupled position. [Figure 4] FIG. 4 is a partial side view of the coupling device of FIGS. 1 to 3, showing a first coupling portion and a disk of the coupling device. [Diagram 5] FIG. 5 is a cutaway cross-sectional view taken along section VV of FIG. 4, showing in particular the first connecting part, the disk and the housing of the connecting device. [Figure 6] FIG. 6 is a partial side view of a coupling device according to an alternative embodiment showing a first coupling portion, a housing and a disk of the coupling device. [Figure 7] FIG. 7 is a cross-sectional cutaway view with intersecting planes taken along section VII-VII of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] In the specification and claims, the terms "outer" and "inner" and "axial" and "radial" are used to designate elements of the transmission system according to the definition given herein. By convention, a "radial" orientation is oriented perpendicular to the axis of rotation X of the transmission system which defines the "axial" orientation, and a "circumferential" orientation is oriented perpendicular to the axis X and perpendicular to the radial direction from the inside to the outside away from said axis.

[0083] Figures 1 to 5 show a transmission system 1 according to a first embodiment. The transmission system is here a differential used in a vehicle drive train to transmit and distribute torque from a motor, not shown, to two wheel shafts 2, 3 of a motorized vehicle axle. Such a transmission system may form part of a secondary drive train capable of transmitting torque from a secondary motor of the vehicle, such as an electric motor, to the rear or front axle of the vehicle, while a primary drive train may transmit torque from a main motor, such as an internal combustion engine, to the wheel shafts of another axle of the vehicle. According to other embodiments not shown, the transmission system may take other forms than that of a differential.

[0084] The transmission system comprises a first element 4 movable for rotation about an axis X and intended to be driven by a motor, such as an electric motor (not shown), a second element 5 also movable for rotation about the axis X and intended to drive the wheel shafts 2, 3, and a coupling device 6 capable of selectively coupling or decoupling the first element 4 and the second element 5.

[0085] The first element 4 comprises a toothed wheel 7 intended to be driven by a motor via a reduction gear train, not shown. This first element 4 also comprises a housing 8 fixed for rotation to the toothed wheel 7. The housing 8 comprises two parts 9, 10 fixed to one another. To this end, in the embodiment shown, the two parts 9, 10 each comprise an outer flange 11, 12 by means of which the two parts 9, 10 are fixed to the toothed wheel 7 and to one another.

[0086] The second element 5 comprises an annular shaped carrier ring 13 guided for rotation about axis X inside the housing 8. For this purpose, the housing 8 comprises an inner cylindrical part which cooperates with the cylindrical outer periphery of the carrier ring 13 and guides it for rotation relative to the housing 8. The second element 5 further comprises two planetary gears 14, 15 visible in FIG. 1, which are mounted for rotation on the carrier ring 13 about axis Z perpendicular to axis X. The two planetary gears 14, 15 each comprise bevel gear teeth which mesh with complementary bevel gear teeth of two sun gears 16, 17. The two sun gears 16, 17 are movable for rotation about axis X and are each locked for rotation with one of the two wheel shafts 2, 3. The carrier ring 13, the planetary gears 14, 15 and the sun gears 16, 17 form a differential which allows the two wheel shafts 2, 3 to rotate at different speeds.

[0087] Furthermore, the transmission system 1 comprises a coupling device 6, which in the coupled position allows to transmit torque between one of the elements of the second element 5, in this case the carrier ring 13, and the first element 4. The transmission system thus allows to transmit torque from the motor to the wheel shafts 2, 3, by exerting the function of a differential allowing different speeds of rotation of the wheel shafts 2, 3 when the coupling device 6 is in the coupled position. However, in another embodiment (not shown), the coupling device is arranged to couple the first element 4 to one of two sun gears 16, 17. The sun gears 16, 17 have two sets of teeth, preferably axially back to back, one cooperating with the planetary pinion and the other with the first coupling part. In such an embodiment, the carrier ring 13 is locked in rotation by the housing 8, the coupling device being intended to prevent the two wheel shafts 2, 3 from rotating at different speeds.

[0088] Returning to the embodiment shown, it can be seen that the coupling device 6 comprises a first coupling part 18 which is axially movable along the axis X relative to the housing 8, while being locked for rotation by the housing 8. The first coupling part 18 is movable between a decoupled position shown in Fig. 2 and a coupled position shown in Fig. 3. In the decoupled position, the first coupling part 18 is decoupled from the second coupling part 19 which is locked for rotation by the carrier ring 13, such that torque transmission between the housing 8 and the carrier ring 13 is interrupted. On the other hand, in the coupled position, the first coupling part 18 is coupled to the second coupling part 19, which allows torque transmission between the housing 8 and the carrier ring 13.

[0089] In the embodiment shown, the coupling device 6 is a dog clutch device. Thus, one of the first coupling part 18 and the second coupling part 19 is provided with teeth, while the other is provided with a corresponding groove in which said teeth engage when the first coupling part 18 is in the coupled position. In the embodiment shown, the second coupling part 19 is formed integrally with the carrier ring 13. In other words, the side of the carrier ring 13 facing the first coupling part 18 is formed with teeth or grooves. However, although the invention is described in connection with a dog clutch coupling device, it is not limited thereto, and the coupling device may be of other types, in particular a friction coupling device.

[0090] As shown in Fig. 5, the first connecting part 18 comprises an inner part 20 accommodated inside the housing 8, an outer part 21 arranged outside the housing 8 and connection parts 22 regularly distributed around the axis X and each passing through a corresponding through opening 23 formed in the housing 8, which allows the first connecting part 18 to be rotatably fixed relative to the housing 8 while allowing a relative axial movement between the first connecting part 18 and the housing 8. In the embodiment shown, the inner part 20 is annular, while the outer part 21 comprises axially extending lugs in the continuation of the connection parts 22. However, according to another variant embodiment, the structure is inverted, and the outer part 21 is annular, while the inner part 20 comprises a plurality of axially oriented lugs in the continuation of the connection parts 22.

[0091] Furthermore, the coupling device 6 comprises an actuator 24, shown in Figures 1 to 3, which allows the first coupling part 18 to be moved axially. The actuator 24 comprises a casing 25, which is mounted by means of a fixed member (not shown) on the chassis of the vehicle, fixed for rotation with respect to the latter. The casing 25 comprises an inner skirt 26 which is fitted around a portion of the part 9 of the housing 8. The inner skirt 26 comprises a cylindrical guide portion which cooperates with a corresponding cylindrical portion of the housing 8, thereby allowing the housing 8 to rotate relative to the fixed casing 25 of the actuator 24.

[0092] The actuator 24 is an electromagnetic actuator. It comprises an electromagnet 27 defining an inner housing and a piston 28 axially movable inside the inner housing between a retracted position shown in FIG. 2 and a deployed position shown in FIG. 3. The actuator 24 further comprises a magnetic cap 29, which closes the inner housing and comprises a stop 30, such as a shoulder, which defines the deployed position of the piston 28. The piston 28 comprises an annular shaped body 31 made of a ferromagnetic material, for example iron or steel. The piston 28 further comprises a paramagnetic end piece 32, also annular shaped, which is fixed to the body 31 of the piston 28 and by which the actuating force is transmitted to the first connecting part 18. The paramagnetic end piece 32 of the piston 28 thus makes it possible to avoid undesired leakage of the magnetic flux towards other components of the connecting device 6. The body 31 of the piston 28 further comprises a shoulder 33 intended to abut against the shoulder 30 of the magnetic cap 29 when the piston 28 is in the deployed position.

[0093] When the electromagnet 27 is energized with a current greater than the threshold current, it allows the piston 28 to move from the retracted position illustrated in FIG. 2 to the deployed position illustrated in FIG. 3. When the piston 28 is in the deployed position, the magnetic cap 29 exerts an attractive force on the body 31 of the piston 28, which allows it to be held in the deployed position. The current supplied to the electromagnet 27 may then be reduced as long as it remains greater than said threshold current. When the electromagnet 27 is de-energized or when it is supplied with a current lower than the threshold current, the elastic return means described below, which return the first coupling part 18 to the separated position, allow it to overcome the attractive force between the magnetic cap 29 and the body 31 of the piston 28 and to return the piston 28 from the deployed position to the retracted position.

[0094] The coupling device 6 is also equipped with a target 34 axially fixed to the first coupling part 18. Furthermore, the coupling device 6 comprises a non-contact sensor 35, shown in Fig. 1, which is arranged axially facing the target 34 and is configured to emit a signal representative of the axial distance between the target 34 and the sensor 35. The sensor 35 is thus able to emit a signal representative of the position of the first coupling part 18, which is used to ensure the reliability of the control of the coupling device 6, in particular to check whether the coupling device 6 is actually in the separated or coupled position. The sensor 35 is, for example, a Hall effect sensor.

[0095] Furthermore, the coupling device 6 comprises a disk 36, which is fully visible in Figure 4, which is made in one piece and which is axially fixed to the first coupling part 18. The disk 36 serves a number of functions which will be explained below, thereby making it possible to reduce the cost, complexity and bulk of the coupling device 6.

[0096] Firstly, the disk 36 serves the function of the target 34. For this purpose, the disk comprises an annular portion 37 formed on the radial periphery of the disk 36. This annular portion 37 is arranged axially opposite the sensor 35 and thus forms the target 34.

[0097] Secondly, the disk 36 acts as a resilient return means enabling the first coupling portion 18 to return to the disengaged position when the piston 28 of the actuator 24 returns to the retracted position.

[0098] For this purpose, the disk 36 comprises elastic blades 41, four in the embodiment shown. Each of the elastic blades 41 has a free end 42 resting against a bearing area of ​​the housing 8 and a proximal end connected to the remainder of the disk 36. Each of the elastic blades 41 is formed in a window 43 arranged radially inside the annular part 37. The elastic blades 41 extend in a circumferential direction about the axis X, which makes it possible to obtain, for a given radial bulk, a larger length of the elastic blade 41 and, consequently, a smaller stiffness of the elastic blade 41. As shown in Figures 2, 3 and 5, the free end 42 of the elastic blade 41 rests against the end of a stud 44 which projects axially from the housing 8 towards the disk 36. The stud 44 projects an axial dimension greater than the movement of the first connection part 18 between the separated position and the connected position. Advantageously, as shown in FIG. 3, the axial dimension of the stud 44 is such that the elastic blade 41 extends substantially in the plane of the annular portion 37 forming the target 34 when the coupling device 6 is in the separated position.

[0099] Thus, each elastic blade 41 forms an elastic return portion, which is configured to bend elastically during movement of the first connecting portion 18 from the separated position to the connected position, and in response, the elastic blade 41 exerts a return force capable of returning said first connecting portion 18 to the separated position.

[0100] Furthermore, the disk 36 comprises a number of fastening tabs 38 visible in Fig. 4, four in the embodiment shown. The fastening tabs 38 are distributed circumferentially around the axis X and each comprises a free end 39 defining a fastening area fixed to the outer part 21 of the first connecting part 18. The fastening tabs 37 are formed in windows 40 formed in a part of the disk 36 arranged radially inside the annular part 37 forming the target 34. Each window 40 associated with a tab is thus arranged circumferentially between two windows 43 associated with a resilient blade. The fastening tabs 38 project radially inwards from the radially outer edge of said windows 40. Furthermore, the lugs of the outer part 21 pass through said windows 40. Furthermore, as shown in Figs. 2, 3 and 4, the lugs of the outer part 21 each comprise a groove into which the free end 39 of one of the fastening tabs 38 fits, which simply allows the fastening of the disk 36 to the first connecting part 18 without using any additional fastening members.

[0101] By way of example, according to one embodiment, the disk 36, and more particularly the fixing tab 38 and the resilient blade 41, are dimensioned to generate a stiffness K1 of 5-50 N / mm against axial movement of the first connecting portion 18 towards the connecting position.

[0102] Thirdly, the disk 36 also allows the transmission of actuation forces between the piston 28 of the actuator 24 and the first connecting part 18. For this purpose, the piston 28 of the actuator 24 contacts against an inner annular part 45 of the disk 36, which defines an actuation area. Moreover, the disk 36 is capable of elastically deforming between said actuation area and the free end 39 of the fixing tab 38, when the piston 28 of the actuator 24 is moved from the retracted position to the deployed position. This makes it possible to compensate for the dimensional chain tolerances of the coupling device 6 by ensuring that the piston 28 and the first connecting part 18 move over their entire movement during their respective movements to the deployed position and to the connected position. In other words, this makes it possible to ensure both that the piston 28 is adjacent to the magnetic cap 29 of the actuator 24 in the deployed position, and that the first connecting part 18 is axially adjacent to the second connecting part 19 in the connected position. As shown in Fig. 5, the inner annular portion 45 of the disc 36 is separated from the contact area of ​​the first connecting part 18 by an axial clearance 49 which is larger than the axial manufacturing tolerance of the coupling device 6. The axial clearance 49 is, for example, 0.2-1.5 mm. Thus, during the movement of the piston 28 of the actuator 24 from the retracted position to the deployed position, the disc 36 and in particular its inner annular portion 45 deforms in order to compensate for the axial manufacturing tolerance of the coupling device, after which the inner annular portion 45 of the disc 36 comes into contact against the contact area of ​​the first connecting part 18 when said axial manufacturing tolerance of the coupling device 6 is compensated.

[0103] According to an advantageous embodiment, the disk 36 has circumferentially extending notches 46 in the region located radially between the window 43 and an inner annular portion 45 of the disk 36 that defines the working region, as shown in particular in Figure 4. Such notches 46 are advantageous in that they further increase the flexibility of the disk 36.

[0104] By way of example, according to one embodiment, the disk 36 is dimensioned so as to generate a stiffness K2 of between 50 and 500 N / mm against the axial approach of the piston 28 of the actuator 24 towards the first connecting part 18. The stiffness K2 is greater than the stiffness K1. Advantageously, the stiffness K2 is between 4*K1 and 20*K1.

[0105] Fourthly, the disk 36 proposes a sliding interface which limits the friction forces caused by the relative rotation of the disk 36, which is movable in rotation about the axis X, with respect to the piston 28, a part of which is fixed for rotation. According to an advantageous variant, in order to further limit the friction prone to occur between the piston 28 and the disk 36, the annular portion 45 of the disk 36 is provided, on its face facing the piston 28, with an oil passage groove 47, which is shown in FIG.

[0106] The disk 36 is made of spring steel, for example XC70 steel, advantageously prehardened. By way of example, the disk 36 has a thickness of 0.4 to 1.2 mm, for example of the order of 0.8 mm. Alternatively, the disk 36 is made of stainless steel.

[0107] Figures 6 and 7 show a coupling device 6 according to another embodiment. This coupling device 6 differs from the one described above in connection with Figures 1 to 5 only in the way in which the disk 36 is fixed to the first connecting part 18. In this embodiment, the free end 39 of each fixing tab 38 is fixed to the outer side 21 of the first connecting part 18 by means of a fixing member 48, such as a screw, which makes it possible to ensure a greater rigidity of the fixation of the disk 36 to the first connecting part 18.

[0108] Although the invention has been described with reference to some specific embodiments, it is extremely clear that it is in no way limited thereto, and that it includes all technical equivalents of the described means and combinations thereof, provided that these are within the scope of the invention as defined by the claims.

[0109] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A transmission system (1) for a motor vehicle, comprising: a first element (4) and a second element (5) movable in rotation relative to each other about an axis X, one of the first and second elements (4, 5) adapted to be driven by a motor and the other of the first and second elements (4, 5) adapted to drive at least one wheel shaft (2, 3) of said motorized vehicle; a coupling device (6) comprising: a first connecting part (18) that is locked in rotation relative to the first element (4) and a second connecting part (19) that is locked in rotation relative to the second element (5), the first connecting part (18) being movable relative to the first element (4) between a connected position and a disconnected position, in which the first connecting part (18) is connected to the second connecting part (19) to transmit torque between the first element (4) and the second element (5), and in which the first connecting part (18) and the second connecting part (19) are disconnected from each other; a disk (36) including a fixing area axially fixed to said first connecting part (18), said disk (36) comprising an annular portion (37) forming a target (34) and at least one elastic return portion (41) configured to elastically deform during movement of said first connecting part (18) from said separated position to said connected position and to exert a return force capable of elastically returning said first connecting part (18) to said separated position, The first element (4) comprises a housing (8) in which the second connecting portion (19) is housed; the housing (8) is provided with plots (44) projecting axially outwardly of the housing (8) in the direction of the discs (36), each plot (44) having one end forming one of the bearing areas of the transmission system (1); The free end (42) of the elastic blade of the at least one elastic return portion (41) rests against the end of the plot (44); the plot (44) projects an axial dimension greater than the amount of movement of the first coupling portion (18) between the disconnected position and the coupled position; Transmission system (1).

2. 2. A transmission system (1) according to claim 1, comprising a sensor (35) arranged facing the annular portion of the disc (36), the sensor (35) being configured to emit a signal representative of the distance between the annular portion forming a target (34) and the sensor (35).

3. 3. A transmission system (1) according to claim 1 or 2, wherein the disc (36) comprises a plurality of elastic return portions each having an elastic blade (41) capable of leaning against the bearing area, the bearing area being axially fixed relative to the second connecting portion.

4. The transmission system (1) according to any one of claims 1 to 3, wherein the first connecting portion (18) comprises an inner portion (20) accommodated inside the housing (8), an outer portion (21) positioned outside the housing (8), and a plurality of connection portions (22) axially connecting the outer portion (21) and the inner portion (20) of the first connecting portion (18), each of the connection portions (22) passing through a corresponding through opening (23) formed in the housing (8).

5. 5. A transmission system (1) according to claim 4 in combination with claim 3, wherein the disc (36) is arranged outside the housing (8) and fixed to the outer part (21) of the first connecting part (18), and each bearing area is located in the housing (8).

6. 6. A transmission system (1) according to claim 4 or 5, wherein the second element (5) comprises a carrier ring (13) guided to rotate about an axis X inside the housing (8), two planetary gears (14, 15) mounted on the carrier ring (13) to rotate about an axis Z perpendicular to the axis X, and two sun gears (16, 17) movable to rotate about the axis X, engaged respectively with the two planetary gears (14, 15), and each locked in rotation relative to the wheel shafts (2, 3).

7. 7. A transmission system according to claim 6, wherein the second coupling part (19) of the coupling device (6) is locked against rotation relative to the carrier ring (13) with respect to the axis X.

8. The transmission system (1) according to any one of the preceding claims, wherein the disc (36) comprises a plurality of fixing tabs (38) fixed to the first connecting portion (18).

9. 9. The transmission system (1) according to any one of claims 1 to 8, wherein the coupling device (6) further comprises an actuator (24) including a casing (25) intended to be fixed to the chassis of the vehicle and a piston (28) axially movable relative to the casing (25) between a retracted position and a deployed position, the piston (28) bearing against an active area of ​​the disc (36) such that movement of the piston (28) from the retracted position to the deployed position causes movement of the first coupling part (18) of the coupling device (6) from the disengaged position to the coupled position, the disc (36) being elastically deformable between the fixed area and the active area of ​​the disc (36) during movement of the piston (28) of the actuator (24) from the retracted position to the deployed position.

10. 10. The transmission system of claim 9, wherein the active area of ​​the disc is separated from the contact area of ​​the first connecting portion by an axial clearance, the axial clearance being dimensioned such that the disc deforms during movement of the piston of the actuator from the retracted position to the deployed position to compensate for axial manufacturing tolerances of the coupling device, such that the active area of ​​the disc comes into contact with the contact area of ​​the first connecting portion when the axial manufacturing tolerances of the coupling device are compensated.

11. 11. The transmission system (1) according to claim 9 or 10, wherein the disc (36) is dimensioned to create a stiffness of 50 to 500 N / mm against the axial approach of the piston (28) towards the first connecting portion (18).

12. A transmission system (1) according to any one of claims 9 to 11, wherein the active area of ​​the disc (36) is an inner annular portion (45).

13. 13. The transmission system (1) of claim 12, wherein the inner annular portion (45) includes an oil passage groove (47).

14. 14. A transmission system (1) according to any one of claims 1 to 13, wherein the coupling device (6) is a dog clutch device, one of the first coupling part and the second coupling part (18, 19) having teeth and the other having corresponding grooves in which the teeth engage when the first coupling part (18) is in the coupled position.

15. The transmission system (1) according to any one of claims 1 to 14, wherein the coupling device is a disconnecting device capable of selectively disconnecting the transmission of torque between the first element and the second element.

16. A motor vehicle comprising an electric machine and a transmission system (1) according to any one of claims 1 to 15, wherein the first element of the transmission system is driven by the electric machine.

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