HYBRID DRIVE SUBASSEMBLY OF A VEHICLE

Abstract

A hybrid subassembly (10) for driving a vehicle, comprises at least one primary shaft (12), at least one secondary shaft (16), a transmission box (18) comprising at least one intermediate shaft (26) separate from the primary shaft (12) and the secondary shaft (16), and an electromotive group comprising at least one reversible electric machine (56), and a coupling device (58) which, in at least one secondary coupling position, kinematically connects the output shaft (57) of the reversible electric machine (56) to the secondary shaft (16) without passing through the intermediate shaft (26), said hybrid subassembly comprising a multi-disc type shaft braking device (90) engaged with the output shaft (57) and arranged to brake the secondary shaft (16) when the coupling device is in the secondary coupling position. (Abstract Figure: Figure 1)

Description

Title of the invention: HYBRID DRIVE SUB-ASSEMBLY OF A VEHICLE Technical field of the invention

[0001] The invention relates to a hybrid drive subassembly of a vehicle intended to be positioned between an engine, for example a thermal engine, and a set of one or more drive wheels of a vehicle. It relates in particular, although not exclusively, to such a subassembly intended to equip a heavy goods vehicle, that is to say a road vehicle of more than 3.5 tonnes, in particular a road tractor. The vehicle may also be a coach. The invention also relates to a method of braking this vehicle comprising such a hybrid subassembly. state of the prior art

[0002] In document WO2011 / 072986A1, a hybrid drive subassembly of a vehicle is described, comprising a primary shaft intended to be driven by a heat engine of the vehicle, a secondary shaft intended to drive a set of one or more drive wheels of the vehicle, and a transmission box comprising one or more primary toothed wheels integral in rotation with the primary shaft or capable of being coupled to the primary shaft, a plurality of secondary toothed wheels integral in rotation with the secondary shaft or capable of being coupled to the secondary shaft, and two intermediate shafts to which intermediate toothed wheels are rotationally secured, the primary toothed wheel(s) and the secondary toothed wheels each meshing with a corresponding toothed wheel among the intermediate toothed wheels.The hybrid drive subassembly further comprises a reversible electric machine kinematically linked to the intermediate shafts via an upstream reduction stage and a dog clutch mechanism, said electric machine being capable of operating as a current generator for braking the intermediate shafts or as a drive motor for the intermediate shafts.Such an electric machine makes it possible to envisage different operating modes, and in particular a transient operation of the electric machine to brake or accelerate the intermediate shafts and promote the synchronization of the transmission box in the transmission ratio change phases, a motor operation to assist the drive of the main engine of the vehicle outside the ratio change phases and an electric generator operation, for the electrical supply of vehicle accessories or a battery, in particular in vehicle braking phases. In this hybrid subassembly, the machine. The reversible electric motor is arranged in line with the heat engine, that is to say that the rotor of the electric machine is concentric with the output of the heat engine.

[0003] In document WO2011 / 072986A1, the reversible electric machine is necessarily kinematically linked to the secondary shaft via the intermediate shaft. This connection with the secondary shaft cannot be direct so that certain operating modes are not optimized in terms of mechanical efficiency, in particular the battery regeneration phase. In this operating mode, the torque from the vehicle wheels must pass through the entire transmission box to enter the reversible electric machine and allow it to operate in electric generator mode.

[0004] It is therefore necessary to envisage a mechanical configuration making it possible to kinematically link the reversible electric machine directly to the secondary shaft with a suitable gear ratio to envisage new functionalities such as the vehicle braking assistance mode without intervention of the intermediate shaft. Statement of the invention

[0005] The invention aims to remedy the drawbacks of the state of the art and to propose better integration of an electric machine into the intermediate and secondary shafts of a transmission box, making it possible to envisage previously inaccessible operating modes.

[0006] To this end, according to a first aspect of the invention, a hybrid subassembly for driving a vehicle is proposed, of the type comprising: at least one primary shaft, at least one secondary shaft and a transmission box comprising at least one intermediate shaft separate from the primary shaft and the secondary shaft and toothed wheel sets for producing several transmission ratios between the primary shaft and the secondary shaft via the intermediate shaft. The hybrid subassembly also comprises an electromotive group comprising at least one reversible electric machine, and a coupling device which, in at least one secondary coupling position, kinematically connects the output shaft of the reversible electric machine to the secondary shaft without passing through the intermediate shaft.Remarkably, the hybrid subassembly comprises a multi-disc type shaft braking device engaged with the output shaft and arranged to brake the secondary shaft when the coupling device is in the secondary coupling position.

[0007] In the secondary coupling position, the coupling device allows direct transmission of power between the reversible electric machine and the secondary shaft without driving the intermediate shaft. This makes it possible to envisage in particular a vehicle braking assistance mode in which the shaft braking device is arranged to slow down the secondary shaft. The shaft braking device of the hybrid subassembly makes it possible to perform the function of slowing down the vehicle when it is on a low percentage slope and for which the driver does not want to use his main braking system. In this braking assistance mode, the braking capacity of the multi-disc type shaft braking device can be between 20% and 60% of the braking capacity of the reversible electric machine. The vehicle slowing down function without a shaft braking device would require a high-power reversible electric machine. It is necessary to dissipate a large quantity of energy over a short time.The reversible electric machine used alone for this slowing function should then have specific maximum power characteristics for this application. The shaft braking device provides the necessary additional braking of the secondary shaft and makes it possible to reduce the size of the reversible electric machine while ensuring the other operating modes. The cost of the reversible electric machine is thus reduced.

[0008] Preferably, the shaft braking device may be engaged directly or indirectly with the output shaft. For the purposes of the invention, when the shaft braking device is in direct engagement with the output shaft, one of the components of the shaft braking device meshes directly or is rotated directly by the output shaft. When the shaft braking device is in indirect engagement with the output shaft, one of the components of the shaft braking device meshes with a transmission shaft kinematically connected to the output shafts. The kinematic connection may be made using a gear, a belt or a transmission chain. In this second case, one of the components of the shaft braking device directly meshes with the associated transmission shaft. Thus, the shaft braking device is indirectly engaged with the output shaft by braking the associated transmission shaft.

[0009] The direct transmission of power between the reversible electric machine and the secondary shaft without driving the intermediate shaft also makes it possible to envisage other operating modes which will be described later, including: a mode of permanent electric drive of the secondary shaft by the reversible electric machine operating as a motor, a transient mode for maintaining traction during gear changes, a pure regenerative braking mode minimizing the resistive mechanical torque.

[0010] Preferably, the shaft braking device comprises a multi-disc assembly.

[0011] Advantageously, the multi-disc type shaft braking device may be interposed in the direction of torque transmission between the rotor of the machine reversible electric and coupling device.

[0012] Preferably, the multi-disc type shaft braking device can be interposed axially between the rotor of the reversible electric machine and the coupling device.

[0013] Advantageously, the multi-disc type shaft braking device may comprise a rotating disc carrier arranged to be connected in rotation with the output shaft, a static disc carrier arranged to be connected in rotation with a fixed part of the transmission box and a multi-disc assembly consisting of a first set of discs engaged with splines of the rotating disc carrier, and a second set of discs engaged with splines of the static disc carrier.

[0014] The rotating disc carrier of the shaft braking device may be rotationally connected by spline to the output shaft or rigidly fixed to the output shaft by means of fixing screws, rivets or by welding.

[0015] According to a variant of the invention, the multi-disc assembly of the shaft braking device can be pressed axially by an annular-shaped actuating piston, coaxial with the output shaft of the reversible electric machine, the actuating piston being guided axially within a pressure chamber formed directly or indirectly in a stator of the reversible electric machine. This shaft braking device structure has the advantage of being radially compact and of being able to be easily integrated within a transmission box.

[0016] According to another variant of the invention, the multi-disc assembly of the shaft braking device can be pressed axially by an annular-shaped actuating piston, coaxial with the output shaft of the reversible electric machine, the actuating piston being guided axially within a pressure chamber formed directly or indirectly in the casing of the transmission box.

[0017] According to another variant of the invention, the coupling device can be interposed axially between the rotor of the reversible electric machine and the multi-disc type shaft braking device.

[0018] Advantageously, the multi-disc assembly of the shaft braking device can be pressed axially by an annular-shaped actuating piston, coaxial with the output shaft of the reversible electric machine, the actuating piston being guided axially within a pressure chamber formed directly or indirectly in a casing of the transmission box.

[0019] Preferably, the coupling device may comprise several coupling positions, in particular a first intermediate coupling position, distinct from the secondary coupling position, which kinematically connects the output shaft of the reversible electrical machine to the intermediate shaft, and the multi-disc type shaft braking device engaged with the output shaft of the subassembly hybrid is arranged to brake the intermediate shaft when the coupling device is in the first intermediate coupling position.

[0020] The coupling device may comprise a plurality of coupling and / or uncoupling positions, for example three distinct coupling positions, allowing power to be transmitted from the reversible electric machine to the intermediate shaft or the secondary shaft according to different transmission ratios.

[0021] The reversible electrical machine may in particular be a permanent magnet synchronous machine, an asynchronous machine, a variable reluctance electrical machine or a variable reluctance synchronous electrical machine, known as synchro-reluctant.

[0022] According to one embodiment, the coupling device, in at least one uncoupling position, simultaneously kinematically uncouples the output shaft of the reversible electric machine from the intermediate shaft and from the secondary shaft. This position of the coupling device makes it possible to implement additional operating modes in which the electric machine is uncoupled, either because it is not necessary for the operation of the transmission box, or because it is used for other purposes, for example for driving another rotating member. The decoupling of the electric machine makes it possible to limit the inertia and the resistive torque at the intermediate shaft, and to relieve the guide bearings of its rotor, which increases their service life.

[0023] According to one embodiment, the coupling device comprises at least one coupling mechanism kinematically permanently linked to the output shaft of the reversible electrical machine, an intermediate speed reducer kinematically permanently linked to the intermediate shaft and a secondary speed reducer kinematically permanently linked to the secondary shaft. The secondary speed reducer may advantageously comprise a reversing gear wheel guided in rotation by a guide bearing coaxial with the intermediate shaft.

[0024] The reversible electric machine may preferably be dimensioned so as to be fully operational for wide operating ranges in the various operating modes envisaged. Thus, it is preferentially provided that the reversible electric machine meets one or more of the following criteria: • the reversible electric machine is capable of continuously developing a motor torque greater than 300 Nm, and preferably greater than 350 Nm, in a speed range of more than 1000 rpm, and preferably more than 2000 rpm inclusive having a lower limit which is less than 6000 rpm, and preferably less than 5000 rpm, and an upper limit which is greater than 6000 rpm, preferably greater than 7000 rpm, and preferably greater than 9000 rpm; • the reversible electric machine is capable of developing a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, for 30 seconds; • the reversible electric machine is capable of developing an engine torque greater than 50 Nm and preferably greater than 60 Nm in a speed range of more than 5500 rpm, and preferably more than 7000 rpm having a lower limit which is less than 5000 rpm, and preferably less than 4500 rpm and an upper limit which is greater than 10000 rpm, and preferably greater than 11000 rpm, for 5 seconds in transient gear change regime.

[0025] In practice, the coupling device in the first intermediate coupling position kinematically connects the output shaft of the reversible electric machine to the intermediate shaft with a so-called intermediate transmission ratio while the coupling device in the secondary coupling position kinematically connects the reversible electric machine to the secondary shaft with a so-called secondary transmission ratio. According to an exemplary embodiment, the coupling device meets one or more of the following criteria: • the secondary transmission ratio is greater than 6, and preferably greater than or equal to 8; • the upper intermediate transmission ratio 4, and preferably greater than or equal to 6 between the intermediate shaft and the output shaft of the reversible electric machine; • the secondary transmission ratio is strictly greater than the intermediate transmission ratio, preferably with a factor greater than or equal to 1.5 between the secondary transmission ratio and the intermediate transmission ratio.

[0026] It may be advantageous to have several transmission ratios between the reversible electric machine and the intermediate shaft and / or between the reversible electric machine and the secondary shaft. For this purpose, the coupling device, in an additional intermediate coupling position, kinematically connects the reversible electric machine to the intermediate shaft with an additional intermediate transmission ratio distinct from the intermediate transmission ratio.

[0027] According to a particularly advantageous embodiment, the subassembly hybrid further comprises a power take-off member, capable of being driven at least by the reversible electric machine, preferably in one of the following ways: • the power take-off member is kinematically linked permanently to the intermediate shaft; • the power take-off member is kinematically connected to the intermediate shaft via the coupling device in the intermediate coupling position; • the power take-off member is kinematically connected to the output shaft of the reversible electric machine via the coupling device in the intermediate coupling position.

[0028] According to this embodiment, the power take-off member can be coaxial with the intermediate shaft.

[0029] According to another particularly advantageous embodiment, the hybrid subassembly comprises a power take-off member, capable of being driven at least by the reversible electric machine, the power take-off member being kinematically linked permanently to the output shaft of the reversible electric machine.

[0030] According to another particularly advantageous embodiment, the electromotive group may comprise two reversible electric machines each comprising a rotor with an output shaft rotating about an axis of rotation, the two output shafts meshing simultaneously on a common toothed wheel arranged parallel to the two axes of rotation, the shaft braking device being indirectly engaged with the output shafts by braking the associated common toothed wheel. In this way, the use of two reversible electric machines improves the traction capacity of the vehicle operating in the mode of permanent electric drive of the secondary shaft by the reversible electric machine. The association of the shaft braking device with the common toothed wheel makes it possible to distribute the braking assistance mode of the vehicle over the two reversible electric machines.

[0031] It is then possible to envisage driving the power take-off by the reversible electric machine without using the main engine of the vehicle, which makes it possible to achieve rotation speeds very significantly higher than 1000 rpm, for example higher than 1500 rpm, and where appropriate up to 5000 rpm.

[0032] In practice, the transmission box can advantageously comprise: • one, or preferably several primary gear wheels capable of being coupled to the primary shaft, for example by one or more coupling and uncoupling mechanisms, for example synchronizers or / and dogs, • several secondary gear wheels capable of being coupled to the secondary shaft, for example by one or more coupling and decoupling mechanisms coupling, for example synchronizers or / dog clutches, • intermediate gear wheels permanently secured to the intermediate shaft, the primary gear wheel(s) and the secondary gear wheels each permanently meshing with a corresponding gear wheel among the intermediate gear wheels to form the gear wheel trains.

[0033] In practice, the transmission box comprises coupling mechanisms for alternately coupling each of the primary gear wheels to the primary shaft, and each of the secondary gear wheels to the secondary shaft. Where appropriate, the hybrid subassembly may further comprise a friction clutch, dry or wet, intended to be arranged between the primary shaft and the main engine.

[0034] Various configurations of the primary gear wheels, the secondary gear wheels, the intermediate shaft and the rotor of the reversible electric machine are conceivable.

[0035] According to one embodiment, the primary shaft and the secondary shaft have axes of revolution which coincide. Alternatively, these axes are parallel and distant.

[0036] According to an exemplary embodiment, the output shaft of the reversible electrical machine has an axis of revolution parallel to an axis of revolution of the intermediate shaft, one or more of the following characteristics preferably being achieved: • the axis of revolution of the output shaft coincides with the axis of revolution of the intermediate shaft; • the axis of revolution of the output shaft is distant from the axis of revolution of the intermediate shaft; • the axis of revolution of the output shaft is distant from an axis of revolution of the primary shaft; • the axis of revolution of the output shaft is distant from an axis of revolution of the secondary shaft.

[0037] According to an exemplary embodiment, the coupling device comprises an epicyclic gear train arranged kinematically between the output shaft and the secondary shaft.

[0038] According to different variants, the coupling device comprises one or more of the following coupling mechanisms: • a dog mechanism, • a synchronizer mechanism, • a clutch mechanism, preferably a friction clutch mechanism, preferably wet, • a double friction clutch, preferably wet, • a triple friction clutch, preferably wet.

[0039] In particular, a dog clutch mechanism without synchronization could be considered in cases where it is intended that the electric machine itself is used to synchronize the coupling device with the associated gear wheel.

[0040] According to one embodiment, the hybrid subassembly may be equipped with a control unit for the reversible electric machine and the coupling device, and sensors capable of generating a signal representative of a speed of revolution of the intermediate shaft or of a member kinematically linked to it and a signal representative of a speed of revolution of the reversible electric machine or of a member kinematically linked to it. The control unit may in particular be implemented to synchronize the coupling device.Preferably, the control unit is capable, in a state of uncoupling of the coupling device, of controlling the reversible electric machine so that a relative rotation speed between the coupling member kinematically linked to the reversible electric machine and the coupling member kinematically linked to the intermediate shaft achieves a predetermined condition, and, when the predetermined condition is achieved, of controlling a coupling of the coupling device. The predetermined condition may for example be a zero relative rotation speed or a predetermined relative sliding speed.

[0041] According to another aspect of the invention, the latter comprises a hybrid engine group with a main engine, preferably internal combustion, and a hybrid subassembly as described above. The main engine is equipped with a main drive shaft linked to the primary shaft directly or via a clutch or a torque converter.

[0042] Preferably, the control unit of the coupling device is operational to control one or more of the following operating modes: • a braking assistance mode without intervention of the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is uncoupled from the intermediate shaft by acting on the dog mechanisms and simultaneously electrical energy is generated with the reversible electric machine operating as a generator and the shaft braking device is actuated which then applies a braking torque to the output shaft via the pressurized multi-disc assembly. • a transient mode for maintaining traction during a gear change, in which the coupling device is positioned in the secondary coupling position, the main motor is decoupled from the intermediate shaft, and the reversible electric machine is controlled so as to generate a motor torque on the secondary shaft or to minimize a variation in speed of the secondary shaft while a change of gearbox ratio; • a pure regenerative slowing mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is decoupled from the intermediate shaft and electrical energy is generated with the reversible electrical machine operating as a generator; • a direct electric drive mode without the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the intermediate shaft is uncoupled from the secondary shaft, and the reversible electric machine is driven.

[0043] Preferably, the control unit is operational to control one or more of the following operating modes: • a reinforcement mode, in which the transmission box achieves one of the transmission ratios between the primary shaft and the secondary shaft via the intermediate shaft, the main motor is powered so as to drive the primary shaft and exert a main driving torque on the intermediate shaft, the coupling device is positioned in the first intermediate coupling position, and the reversible electric machine generates a reinforcement driving torque on the intermediate shaft, of the same sign as the main driving torque; • a recharging mode, in which the gearbox is positioned so as to connect the primary shaft to the intermediate shaft, the main motor is powered so as to drive the primary shaft and exert a main motor torque on the intermediate shaft, the coupling device is positioned in the first intermediate coupling position, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator; • a transient mode of synchronization of the intermediate shaft when changing one of the transmission ratios of the gearbox, in which the coupling device is positioned in the first intermediate coupling position, the main motor is uncoupled from the intermediate shaft, then the reversible electric machine is controlled so as to bring the intermediate shaft to a set speed allowing the engagement of the secondary toothed wheel before recoupling the main motor to the intermediate shaft; • an indirect electric drive mode, in which the coupling device is positioned in the first intermediate coupling position and the main motor is then decoupled from the intermediate shaft that the intermediate shaft is kinematically linked to the secondary shaft, then the reversible electric machine is controlled according to a vehicle speed setting; • a regenerative braking mode by the intermediate shaft, in which the coupling device is positioned in the first intermediate coupling position, the main motor shaft is decoupled from the intermediate shaft and the reversible electric machine is controlled to operate as a generator; • a hybrid engine braking mode, in which the coupling device is positioned in the first intermediate coupling position, one of the transmission ratios between the primary shaft and the secondary shaft passing through the intermediate shaft being engaged, the primary shaft being kinematically linked to the main drive shaft, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator and kinetic energy is transformed into heat with the main motor developing a resistive torque; • a mode of driving a power take-off, in which the coupling device is positioned in the first intermediate coupling position and the main motor is uncoupled from the intermediate shaft, the intermediate shaft from the secondary shaft, then the reversible electric machine is controlled to drive a power take-off coupled to the intermediate shaft.

[0044] According to another aspect of the invention, it relates to a method for braking a vehicle comprising a hybrid subassembly incorporating all or part of the characteristics mentioned above. With a control unit of the coupling device, a braking assistance mode is controlled without intervention of the intermediate shaft, in which the coupling device is positioned in the secondary coupling position, the secondary shaft is decoupled from the intermediate shaft by acting on the dog mechanisms and simultaneously electrical energy is generated with the reversible electric machine operating as a generator and the shaft braking device is actuated which then applies a braking torque to the output shaft via the pressurized multi-disc assembly, brief description of the figures

[0045] Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended figures.

[0046] [Fig-1] [Fig.l] illustrates a hybrid drive subassembly of a vehicle according to a first embodiment.

[0047] [Fig.2] [Fig.2] illustrates the shaft braking device of the hybrid subassembly according to the first embodiment.

[0048] [Fig.3] [Fig.3] illustrates a hybrid drive subassembly of a vehicle according to a second embodiment.

[0049] [Fig.4] [Fig.4] illustrates a hybrid drive subassembly of a vehicle according to a third embodiment.

[0050] [Fig.5] [Fig.5] illustrates a hybrid drive subassembly of a vehicle according to a fourth embodiment.

[0051] [Fig.6] [Fig.6] illustrates a hybrid drive subassembly of a vehicle according to a fifth embodiment.

[0052] For clarity, identical or similar elements are identified by identical reference signs throughout the figures. DETAILED description of embodiments

[0053] In [Fig.l] is illustrated a hybrid subassembly 10 for driving a vehicle, comprising a primary shaft 12 intended to be driven by a main engine 14 of the vehicle, for example a thermal engine, a secondary shaft 16 intended to drive a set of one or more drive wheels of the vehicle (not illustrated), and a transmission box 18.

[0054] The connection of the main engine 14 to the primary shaft 12 may include a clutch 20 of any suitable type, for example a slip clutch. The connection of the secondary shaft 16 to the wheels of the vehicle may include one or more drive axles.

[0055] The transmission box 18 comprises an intermediate shaft 26 to which intermediate gear wheels 28, 30, 32, 34, 36 are rotationally secured. Two primary gear wheels 38, 40 coaxial with the primary shaft 12, each form a gear train with a corresponding gear wheel 28, respectively 30, among the intermediate gear wheels. The meshing of the gear trains 38, 28 and 40, 30 between primary gear wheels 38, 40 and the corresponding intermediate gear wheels 28, 30 is permanent. A three-position double synchronizer 41 allows one or other of the primary gears 38, 40 to be coupled to the primary shaft 12, and provides a neutral position in which none of the primary gears 38, 40 is coupled to the primary shaft 12. The various gears and primary, secondary and intermediate shafts are housed inside a cavity of a casing 24 of the transmission box 18.

[0056] Secondary gear wheels 42, 44, 46, coaxial with the secondary shaft 16, also each form a gear train with a corresponding gear wheel 32, 34, 36, respectively, among the intermediate gear wheels, one of the gear trains being reversing and comprising an intermediate wheel 48 for producing a reverse gear. The meshings of the gear trains formed by the secondary gear wheels 42, 44, 46 and the corresponding intermediate gear wheels 32, 34, 36 are permanent. A three-position dog clutch without synchronizers 50, positioned between two of the secondary gear wheels 44, 46, allows either one or the other of the two associated secondary gear wheels 44, 46 to be coupled to the secondary shaft 16, or, in an intermediate neutral position, to keep the associated secondary gear wheels 44, 46 decoupled from the secondary shaft 16.

[0057] In this embodiment, the axis of revolution 100 of the primary shaft 12 is aligned with the axis of revolution 200 with the secondary shaft 16, which makes it possible to use the primary end gear wheel 40 alternately as a primary wheel, associated with the primary shaft 12 by the synchronizer 41, or as a secondary wheel associated with the secondary shaft 16. For this purpose, a three-position dog clutch 52 without synchronizers, positioned between the primary end gear wheel 40 and the secondary wheel 42, makes it possible to couple either the primary end gear wheel 40 or the secondary wheel 42 to the secondary shaft 16, and also makes it possible, in an intermediate neutral position, to keep the primary end gear wheel 40 and the secondary wheel 42 decoupled from the secondary shaft 16.

[0058] A transmission box 18 with six forward gears and potentially two reverse gears is thus established, which can, if necessary, be coupled at the output of the secondary shaft 16 to an epicyclic gear train (not shown) in order to obtain a twelve-speed gearbox.

[0059] Remarkably, the hybrid drive subassembly 10 is equipped with an electromotive group 5 comprising a reversible electric machine 56, the output shaft 57 of which rotates around an axis of revolution 300, and a coupling device 58, comprising in this example a three-position dog clutch mechanism 59 without synchronizer and two gear reduction trains 60, 62, 64 66, 68. In a position of connection to the intermediate shaft 26, also called the intermediate coupling position, the coupling device 58 performs a rotational coupling of the output shaft 57 with a so-called intermediate speed reducer 260 comprising here a gear wheel 60 which meshes permanently with a gear wheel 62 secured to the intermediate shaft 26.In a position of connection to the secondary shaft, also called the secondary coupling position, the coupling device 58 performs a coupling of the output shaft 57 with a speed reducer called secondary 264, comprising a toothed wheel 64 which meshes permanently with a reversing toothed wheel 66 which itself meshes permanently with a toothed wheel 68 secured to the secondary shaft 16. Remarkably, it can be provided that the reversing toothed wheel 66 is guided in rotation by a guide bearing 69 coaxial with the intermediate shaft 26. The intermediate shaft 26 can then support the guide bearing 69. Finally, the coupling device 58, in a neutral position, . keeps the output shaft 57 decoupled from the toothed wheels 60, 64. Within the coupling device 58, the transition from the intermediate coupling position to the secondary coupling position is carried out via the coupling mechanism 59 controlled by a control unit 76.

[0060] Where appropriate, the intermediate shaft 26 is equipped with a power take-off 68, intended to allow coupling of one or more accessories of the vehicle, for example a winch, a pump or a tool. The power take-off 68 may be, for example, a transmission shaft comprising an external connection interface, for example a spline.

[0061] The output shaft 57 illustrated in [Fig.l] is integral with the rotor of the reversible electric machine 56 and constitutes a motor shaft. Alternatively, the reversible electric machine may integrate a reducer between the motor shaft and the output shaft 57.

[0062] The reversible electric machine 56 is powered by a battery 70 via a bidirectional current converter 72, which makes it possible to power the reversible electric machine 56 as a motor, and conversely, to turn the reversible electric machine 56 as a generator to power the battery 70.

[0063] The reversible electrical machine 56 is preferably a high voltage machine, powered for example at a nominal voltage between 300 Volts and 800 Volts, capable of delivering significant torque and power, as will be discussed later. The nominal voltage may be greater than 800 volts.

[0064] The control unit 76 makes it possible to control the reversible electric machine 56 and its coupling device 58. To this control unit are connected sensors 78, 80, 82 to measure the speed of revolution of the output shaft 57, of the intermediate shaft 26 and of the secondary shaft 16 or the speeds of revolution of elements permanently driven by these shafts. This control unit 76 can be integrated into a robotic control of the transmission box 18 which controls the opening and closing of the synchronizers 41, of the dog mechanisms 50, 52, and where appropriate of the main clutch 20, to respond to a torque or speed setpoint.

[0065] The electric machine 56 makes it possible to envisage several operating modes, as will be discussed later.

[0066] The hybrid subassembly 10 also comprises a multi-disc type shaft braking device 90 engaged with the output shaft 57 and arranged to brake the secondary shaft 16 when the coupling device 58 is in the secondary coupling position. The shaft braking device 90 comprises a multi-disc assembly 91. The multi-disc type shaft braking device 90 is interposed, in the direction of torque delivery, between the rotor of the machine reversible electric machine 56 and the coupling device 58. Incidentally, the shaft braking device 90 is interposed axially between the rotor of the reversible electric machine 56 and the coupling device 58.

[0067] As illustrated in [Fig.2], the multi-disc type shaft braking device 90 comprises a rotating disc carrier 92 arranged to be rotatably connected to the output shaft 57, a static disc carrier 93 arranged to be rotatably connected to a fixed part of the transmission box 18 and a multi-disc assembly 91 consisting of a first set of discs 91a engaged with splines of the rotating disc carrier, and a second set of discs 91b engaged with splines of the static disc carrier. For example, the rotating disc carrier 92 of the shaft braking device 90 is rotatably connected by spline 94 to the output shaft 57. Alternatively, the rotating disc carrier 92 may be rigidly fixed to the output shaft 57 by means of fixing screws, rivets or by welding.

[0068] In the example of implementation of the invention of [Fig.2], the multi-disc assembly of the shaft braking device 90 is pressed axially by an actuating piston 95 of annular shape, coaxial with the output shaft 57 of the reversible electric machine 56. The actuating piston 95 is guided axially within a pressure chamber 96 formed directly or indirectly in the stator 56a of the reversible electric machine 56.

[0069] Alternatively, the actuating piston 95 can be guided axially within a pressure chamber 96 formed directly or indirectly in the casing of the transmission box 18.

[0070] In [Fig. 3] is illustrated a hybrid subassembly 10 according to a second exemplary embodiment of the invention, which differs from the exemplary embodiment of [Fig. 1] in that the coupling device 58 comprises, in addition to the three-position dog clutch mechanism 59, a two-position dog clutch mechanism 159, which performs a rotational coupling of the output shaft 57 with a second intermediate speed reducer 360 comprising a toothed wheel 160 which permanently meshes with a toothed wheel 162 secured to the intermediate shaft 26. The transmission ratio achieved by the gearing of the toothed wheels 160, 162 is different from the transmission ratio of the gearing of the toothed wheels 60, 62. The coupling mechanism 159, in a neutral position, keeps the output shaft 57 decoupled from the toothed wheel 160.

[0071] Those skilled in the art will understand, without it being necessary to illustrate it in detail, that they could, if necessary, multiply the transmission ratios between the output shaft 57 and the intermediate shaft by adding speed reducers between the coupling mechanisms 59, 159 and the intermediate shaft 26. Similarly, it would be possible to multiply the transmission ratios between the output shaft 57 and the secondary shaft 16 by adding coupling mechanisms and speed reducers between the output shaft 57 and the secondary shaft 16.

[0072] The coupling mechanisms 59, 159 of the coupling device 58 may be of any type, in particular with a dog clutch with or without synchronization or with friction. [Fig. 4] thus illustrates a third exemplary embodiment of the invention, which differs from the exemplary embodiment of [Fig. 1] by the fact that the coupling device 58 comprises a coupling mechanism of the double wet friction clutch type 259. In [Fig. 5], the coupling device 58 comprises a coupling mechanism of the triple wet friction clutch type 359, achieving the same transmission ratios as the exemplary embodiment of [Fig. 3].

[0073] In the exemplary embodiments of the invention according to Figures 3 and 5, the coupling device comprises a plurality of coupling and uncoupling positions, in particular three distinct coupling positions, allowing power to be transmitted from the reversible electric machine to the intermediate shaft or the secondary shaft according to different transmission ratios. The coupling device comprises in particular a first intermediate coupling position, a second intermediate coupling position otherwise called an additional intermediate coupling position and a secondary coupling position. In the second intermediate coupling position, the coupling device 58 kinematically connects the reversible electric machine 56 to the intermediate shaft 26 with a second intermediate transmission ratio distinct from the first intermediate transmission ratio.

[0074] The various embodiments described have in common a coupling device 58 capable of taking at least a first coupling position called intermediate in which the reversible electric machine 56 is kinematically connected to the intermediate shaft, and at least one secondary coupling position in which the reversible electric machine 56 is kinematically connected to the secondary shaft 16 without passing through the intermediate shaft 26. These various couplings can be used to achieve a wide variety of operating modes, as will now be discussed.

[0075] First, several operating modes can be implemented while the coupling device 58 connects the output shaft 57 to the secondary shaft 16 without intervention of the intermediate shaft 26.

[0076] It is possible to envisage a braking assistance mode without intervention of the intermediate shaft 26, in which the coupling device 58 is positioned in the secondary coupling position, the secondary shaft 16 is uncoupled from the intermediate shaft 26 by acting on the dog mechanisms 50, 52 and simultaneously electrical energy is generated with the reversible electrical machine 56 operating in generator and the shaft braking device 90 is actuated, which then applies a braking torque to the output shaft 57 via the pressurized multi-disc assembly 91. This braking assistance mode can be advantageous when the vehicle is on a low-percentage slope and for which the driver does not want to use his main braking system. In this braking assistance mode, the braking capacity of the multi-disc type shaft braking device 90 is between 20% and 60% of the braking capacity of the reversible electric machine 56.

[0077] It is also possible to envisage a pure regenerative braking mode without the intermediate shaft 26, in which the coupling device is positioned in the secondary coupling position, the secondary shaft 16 is uncoupled from the intermediate shaft 26 by acting on the dog mechanisms 50, 52 and electrical energy is generated with the reversible electrical machine 56 operating as a generator. To optimally achieve this regenerative braking mode without the main motor, it is advantageous for the reversible electric machine to be able to develop a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, this for at least 30 seconds.

[0078] Particularly advantageously, other operating modes can be envisaged while the coupling device 58 connects the output shaft 57 to the secondary shaft 16.

[0079] It is thus possible to implement a transient mode for maintaining traction during a gear change, in which the coupling device 58 is positioned in the secondary coupling position, the main motor 14 is uncoupled from the intermediate shaft 26, and the reversible electric machine 56 is controlled so as to generate a motor torque on the secondary shaft 16 or to minimize a variation in speed of the secondary shaft while a gear change of the transmission box 18 is controlled between the main motor 14 and the intermediate shaft 26 and / or between the intermediate shaft 26 and the secondary shaft 16.

[0080] The transient mode of maintaining traction during a gear change and the pure regenerative braking mode without the intermediate shaft 26 are transient operating modes, not intended to last more than about thirty seconds. For information purposes, with a transmission ratio of the order of 8 between the output shaft 57 and the secondary shaft 16, it is advantageous to size the reversible electric machine to develop a resistive torque greater than 400 Nm and preferably greater than 450 Nm in a speed range of more than 3000 rpm, and preferably more than 4000 rpm having a lower limit which is less than 6500 rpm, and preferably less than 6000 rpm and an upper limit which is greater than 9000 rpm, and preferably greater than 10000 rpm, for 30 seconds.

[0081] Finally, a direct electric drive mode can be implemented without the intermediate shaft 26, in which the coupling device 58 is positioned in the secondary coupling position and the intermediate shaft 26 is uncoupled from the secondary shaft 16 at the dog clutch mechanisms 50, 52, the reversible electric machine acting in a driving or regenerative manner depending on the acceleration or braking needs. This operating mode is less flexible than the electric drive mode with the intermediate shaft since the plurality of transmission ratios of the transmission box 18 are not available. But it can be used in addition to the latter, by offering a direct transmission ratio between the output shaft 57 and the secondary shaft 16 higher than the transmission ratios using the transmission box 18.For information purposes, it is possible, for example, to develop two ratios having a value of the order of 4 and 6 respectively, with the dogs 50, 52 of the transmission box 18 combined with the gear train 60, 62 of the coupling device 58, and an additional transmission ratio having a value of the order of 8 by the gear train 64, 66, 68 of the coupling device 58.

[0082] Then, several operating modes can be implemented while the coupling device 58 connects the output shaft 57 to the intermediate shaft 26.

[0083] In a transient mode of synchronization of the intermediate shaft during a gear change, the coupling device 58 is positioned in the first intermediate coupling position, the main motor 14 is uncoupled from the intermediate shaft 26 either at the clutch 20 or at the dog mechanism 41, then the reversible electric machine 56 is controlled so as to bring the intermediate shaft 26 to a set speed allowing the engagement of the secondary toothed wheel before recoupling the main motor 14 to the intermediate shaft 26. During these transient phases, the reversible electric machine 56 thus makes it possible to adapt the speed of revolution of the intermediate shaft to the synchronization needs during the switching of the dog mechanisms 50, 52 or the synchronizers 41.In these phases, the reversible electric machine can be used alternately as an electric motor to increase the speed of revolution of the intermediate shaft 26 or as a generator to reduce this speed. This adaptation of the speed of the intermediate shaft 26 makes it possible to reduce the dog clutch or synchronization times, without having to resort to a gearbox brake.

[0084] In a recharging mode, one of the primary gears 38, 40 is coupled to the primary shaft 12, the main motor 14 is powered so as to drive the shaft primary 12 and to exert a main driving torque on the intermediate shaft 26, the coupling device 58 is positioned in the first intermediate coupling position, and kinetic energy is transformed into electrical energy with the reversible electric machine operating as a generator. Recharging can take place while the intermediate shaft 26 drives the secondary shaft 16 or without connection to the secondary shaft 16.

[0085] In a reinforcement mode, one of the secondary gears 42, 44, 46 is coupled to the secondary shaft 16, one of the primary gears 38, 40 is coupled to the primary shaft, the main motor 14 is powered so as to drive the primary shaft 12 and to exert a main driving torque on the intermediate shaft 26, and the coupling device 58 is positioned in the first intermediate coupling position or one of the intermediate coupling positions if there are several, and the reversible electric machine generates a reinforcing driving torque on the intermediate shaft, of the same sign as the main driving torque. The additional power input for the traction of the vehicle is achieved with one transmission ratio (for the exemplary embodiments of Figures 1 and 4), two transmission ratios (for the exemplary embodiments of Figures 3 and 5), or even more.

[0086] In a pure electric drive mode passing through the intermediate shaft 26, the coupling device 58 is positioned in the first intermediate coupling position and the main motor 14 is uncoupled from the intermediate shaft 26 while one of the secondary toothed wheels 42, 44, 46 is coupled to the secondary shaft 16, then the reversible electric machine is controlled as a function of a vehicle speed setpoint.For information purposes, to implement such an electric drive mode of the vehicle, it is advantageous for the reversible electric machine to be able to continuously develop an engine torque greater than 300 Nm, and preferably greater than 350 Nm, in a speed range of more than 1000 rpm, and preferably more than 2000 rpm inclusive, having a lower limit which is less than 6000 rpm, and preferably less than 5000 rpm, and an upper limit which is greater than 6000 rpm, preferably greater than 7000 rpm, and preferably greater than 9000 rpm. With such an operating range, combined with several transmission ratios of between 4 and 8 produced by the meshing of the toothed wheels 32 and 42, 34 and 44, 60, 62 and where appropriate 160, 162, it is possible to envisage electric operation of the vehicle in urban mode. .

[0087] In a regenerative braking mode via the intermediate shaft, the coupling device 58 is positioned in the first intermediate coupling position, the main motor 14 is decoupled from the intermediate shaft 26, at the clutch 20 or the synchronizers 41, one of the dogs 50, 52 is engaged to connect the intermediate shaft 26 to the secondary shaft 16 and the electric machine re- Versible 56 is controlled to operate as a generator.

[0088] In a hybrid engine braking mode, the coupling device 58 is positioned in the first intermediate coupling position, a kinematic connection is maintained between the main motor 14, the intermediate shaft 26 and the secondary shaft 16, a portion of the kinetic energy transmitted by the secondary shaft 16 is transformed into electrical energy with the reversible electric machine 56 operating as a generator and a portion of the kinetic energy transmitted by the secondary shaft 16 is transformed into heat with the main motor 14 developing a resistive torque. This operating mode makes it possible to achieve a greater braking torque than with the main motor 14 alone.

[0089] The reversible electric machine 56 can also be used as a motor to drive the power take-off 68 while the transmission box 18 is in the neutral position to interrupt the connection between the intermediate shaft 26 and the primary shaft 12 on the one hand, and between the intermediate shaft 26 and the secondary shaft 16 on the other hand.

[0090] In [Fig.6] a fifth embodiment of the invention is illustrated, which differs from the first embodiment by the use of two reversible electrical machines 56, each electrical machine comprising a stator and a rotor having an output shaft movable in rotation around an axis.

[0091] The reversible electrical machines 56 are of the same type and are, for example, permanent magnet synchronous machines. Each electrical machine provides the same nominal mechanical power.

[0092] As can be seen in [Fig.6], the first electrical machine 56 has in the example described a rotor with a first output shaft 57 rotating about a first axis of rotation XI, the second electrical machine 56 has a rotor with a second output shaft 57 rotating about a second axis of rotation X2. In the example described, the axes of rotation of the reversible electrical machines are parallel but not coincident, the two electrical machines 56a, 56b not having their axes of rotation aligned.

[0093] The output shafts 57 of the two electrical machines mesh simultaneously with a common toothed wheel 110 arranged between the axes XI, X2. The common toothed wheel 110 is kinematically connected to the two output shafts and receives the motor torque supplied by the two electrical machines, the latter being distributed around the common toothed wheel 110 so as to form a first speed reducer Z1, Z2. The common toothed wheel 110 is kinematically connected to a transmission shaft 55 specific to the coupling device 58 of this fifth embodiment of the invention using a second speed reducer Z3, Z4.

[0094] Similar to the first embodiment, the coupling device 58 comprises a three-position dog clutch mechanism 59 without synchronizer and two trains gear reducers 60, 62, 64 66, 68. In a position of connection to the intermediate shaft 26, also called the intermediate coupling position, the coupling device 58 performs a rotational coupling of the transmission shaft 55 with a so-called intermediate speed reducer 260 comprising here a toothed wheel 60 which meshes permanently with a toothed wheel 62 secured to the intermediate shaft 26. In a position of connection to the secondary shaft, also called the secondary coupling position, the coupling device 58 performs a coupling of the transmission shaft 55 with a so-called secondary speed reducer 264, comprising a toothed wheel 64 which meshes permanently with a reversing toothed wheel 66 which itself meshes permanently with a toothed wheel 68 secured to the secondary shaft 16.

[0095] The hybrid subassembly 10 also comprises a multi-disc type shaft braking device 90 engaged with the output shafts 57 of the two electrical machines via the common toothed wheel 110 and arranged to brake the secondary shaft 16 when the coupling device 58 is in the secondary coupling position. The shaft braking device 90 comprises a multi-disc assembly 91. The multi-disc type shaft braking device 90 is interposed, in the direction of conveyance of the torque, between the rotor of the reversible electrical machine 56 and the coupling device 58.

[0096] As illustrated in [Fig.6], the multi-disc type shaft braking device 90 comprises a rotating disc carrier 92 arranged to be rotationally connected with the common toothed wheel 110 of rotation axis 111, a static disc carrier 93 arranged to be rotationally connected with a fixed part of the transmission box and a multi-disc assembly 91 constituted by a first set of discs engaged with splines of the rotating disc carrier, and a second set of discs engaged with splines of the static disc carrier. For example, the rotating disc carrier 92 of the shaft braking device 90 is rotationally connected by spline with the common toothed wheel 110.

Claims

Claims

1. Hybrid subassembly (10) for driving a vehicle, comprising: • at least one primary shaft (12); • at least one secondary shaft (16); • a transmission box (18) comprising at least one intermediate shaft (26) separate from the primary shaft (12) and the secondary shaft (16) and sets of toothed wheels (38, 28, 40, 30, 32, 42, 36, 48, 44, 46) for producing several transmission ratios between the primary shaft (12) and the secondary shaft (16) via the intermediate shaft (26); • an electromotive group comprising at least one reversible electric machine (56), and a coupling device (58) which, in at least one secondary coupling position, kinematically connects the output shaft (57) of the reversible electric machine (56) to the secondary shaft (16) without passing through the intermediate shaft (26),characterized in that the hybrid subassembly comprises a multi-disc type shaft braking device (90) engaged with the output shaft (57) for braking the secondary shaft (16) when the coupling device is in the secondary coupling position, and in that the electromotive group comprises two reversible electric machines (56) each comprising a rotor with an output shaft (57) rotating about an axis of rotation (XI, X2), the two output shafts (57) meshing simultaneously with a common toothed wheel (110) arranged parallel to the two axes of rotation (XI, X2), the shaft braking device (90) being engaged indirectly with the output shafts (57) by braking the associated common toothed wheel (110).,

2. Hybrid subassembly (10) according to claim 1, characterized in that the multi-disc type shaft braking device (90) is interposed axially between the rotor of the reversible electric machine (56) and the coupling device (58).

3. Hybrid subassembly (10) according to claim 1 or 2, characterized in that the multi-disc type shaft braking device (90) comprises a rotating disc carrier (92) arranged to be rotationally connected to the output shaft (57), a static disc carrier (93) arranged to being rotationally linked with a fixed part of the transmission box (18) and a multi-disc assembly (91) consisting of a first set of discs (91a) engaged with splines of the rotating disc carrier, and a second set of discs (91b) engaged with splines of the static disc carrier.

4. Hybrid subassembly (10) according to one of the preceding claims, characterized in that the coupling device (58) comprises several coupling positions, in particular a first intermediate coupling position, distinct from the secondary coupling position, which kinematically links the output shaft (57) of the reversible electric machine (56) to the intermediate shaft (26), and the multi-disc type shaft braking device engaged with the output shaft (57) of the hybrid subassembly is arranged to brake the intermediate shaft when the coupling device is in the first intermediate coupling position.

5. Hybrid subassembly (10) according to one of the preceding claims, characterized in that the coupling device (58), in at least one uncoupling position, kinematically uncouples simultaneously the output shaft (57) of the reversible electric machine (56) from the intermediate shaft (26) and from the secondary shaft (16).

6. Hybrid subassembly (10) according to one of the preceding claims, characterized in that the coupling device (58) comprises at least one coupling mechanism (59, 159, 259, 359) kinematically permanently linked to the output shaft (57) of the reversible electric machine (56), an intermediate speed reducer (260, 360) kinematically permanently linked to the intermediate shaft (26) and a secondary speed reducer (264) kinematically permanently linked to the secondary shaft (16).

7. Hybrid subassembly (10) according to the preceding claim, characterized in that the secondary speed reducer (264) comprises a reversing gear wheel (66) guided in rotation by a guide bearing (69) coaxial with the intermediate shaft (26).

8. Hybrid subassembly (10) according to one of the preceding claims, characterized in that the coupling device (58) in the first intermediate coupling position kinematically connects the output shaft (57) of the reversible electric machine (56) to the intermediate shaft (26) with an intermediate transmission ratio, the coupling device (58) in the se- coupling position secondary kinematically links the reversible electric machine (56) to the secondary shaft (16) with a secondary transmission ratio, and in that at least one of the following criteria is met: - the secondary transmission ratio is greater than 6, and preferably greater than or equal to 8; - the intermediate transmission ratio is greater than 4, and preferably greater than or equal to 6 between the intermediate shaft (26) and the output shaft (57) of the reversible electric machine (56); - the secondary transmission ratio is strictly greater than the intermediate transmission ratio, preferably with a factor greater than or equal to 1.5 between the secondary transmission ratio and the intermediate transmission ratio.

9. Hybrid subassembly (10) according to claim 4, characterized in that the coupling device (58), in an additional intermediate coupling position, kinematically connects the reversible electric machine (56) to the intermediate shaft (26) with an additional intermediate transmission ratio distinct from the intermediate transmission ratio.

10. Hybrid subassembly (10) according to one of the preceding claims, characterized in that the output shaft (57) of the reversible electric machine (56) has an axis of revolution (300) parallel to an axis of revolution of the intermediate shaft (26), one or more of the following characteristics preferably being achieved: - the axis of revolution (300) of the output shaft (57) coincides with the axis of revolution of the intermediate shaft (26); - the axis of revolution (300) of the output shaft (57) is distant from the axis of revolution of the intermediate shaft (26); - the axis of revolution (300) of the output shaft (57) is distant from an axis of revolution (100) of the primary shaft (12); - the axis of revolution (300) of the output shaft (57) is distant from an axis of revolution of the secondary shaft (16).

11. Hybrid subassembly according to one of the preceding claims, ca- characterized in that the coupling device (58) comprises one or more of the following coupling mechanisms: - a dog mechanism (59, 159), - a synchronizer mechanism, - a clutch mechanism (259, 359), preferably a friction clutch mechanism, preferably wet, - a double friction clutch (259), preferably wet, - a triple friction clutch (359), preferably wet.

Images