WO2005047040A1

WO2005047040A1 - Double-clutch transmission element for a hybrid traction chain for a motor vehicle and a motor vehicle provided with said element

Info

Publication number: WO2005047040A1
Application number: PCT/FR2004/002611
Authority: WO
Inventors: Stéphane Delporte
Original assignee: Peugeot Citroen Automobiles Sa
Priority date: 2003-11-06
Filing date: 2004-10-13
Publication date: 2005-05-26
Also published as: FR2862025B1; FR2862025A1

Abstract

The inventive transmission element comprises a motion input shaft (37) connectable to a heat engine, a motion output shaft (39) connectable to a gear box, an electric motor (31) consisting of a stator (61) and a rotor (63), a first connecting clutch (33) arranged between the input shaft (37) and the output shaft (39), a second connecting clutch (35) arranged between the rotor (63) and the output shaft (39), one (33) of said clutches being embodied in the form of a wet friction clutch, and the other clutch (35) in the form of a dog clutch.

Description

Double clutch transmission element for a hybrid powertrain of a motor vehicle, and motor vehicle equipped with such an element.

The invention relates to a transmission element for a parallel hybrid type traction chain. By parallel hybrid traction chain is meant a traction chain supplying a wheel shaft with mechanical energy from at least one “irreversible” type motor (generally a heat engine) and from at least one - "reversible" type (usually an electric motor), and in which the energy node from the two motors is mechanical. ^* FIG. 1 shows schematically a parallel hybrid traction chain of known type to which the invention applies more particularly. Such a traction chain 1 therefore essentially comprises a heat engine, (or more generally an irreversible motor) 3, a transmission element 5, and a gearbox 7, the input of which is connected to the transmission element 5 and the output to a wheel shaft 9. The transmission element 5 comprises an electric motor (or more generally a reversible motor) 11 of the hybrid traction chain, as well as a first clutch 13 for connection between the heat engine 3 and the gearbox input shaft 7, and a second clutch 15 connecting the electric motor 11 and the gearbox input shaft 7. The invention therefore relates more particularly to a transmission element for a chain hybrid type traction drive, said element ^' comprising a motion input shaft intended to be connected to a heat engine, a motion output shaft ^' intended to be connected to a gearbox, an electric motor comprising a stator and a rotor, a first connecting clutch between the input shaft and the output shaft, and a second connecting clutch between the rotor and the output shaft. In the known hybrid traction chains, of the type described above, the two connecting clutches, respectively to the heat engine and to the electric motor, are of the same type, generally with friction, more precisely dry or wet. To minimize wear and provide cooling ^efficient clutches, some designers are choosing to use two wet clutches. This choice, which has the advantages mentioned above with respect to the solution with dry clutches, nevertheless has certain drawbacks. - In particular, wet clutches have a relatively large axial size, due to the stacking of a large number of friction discs. In addition, wet clutches are associated with hydraulic lubrication and cooling circuits which are complex and penalizing in terms of space requirement. The object of the invention is to remedy the aforementioned drawbacks and to propose a transmission element of the aforementioned type, one of the clutches is of the wet friction type, and which is of smaller axial size and of less complexity. To this end, according to the invention, the other of said clutches is of the dog clutch type. According to other characteristics of the invention, taken alone or in any technically conceivable combination: - The first clutch is of the wet friction type, and the second clutch is of the dog clutch type; - The two clutches are arranged radially inside the electric motor; and - the transmission element comprises a casing comprising a first half-shell supporting the input shaft in rotation, and a second half-shell supporting the output shaft in rotation, these two half-shells defining a housing in which are mounted coaxially the two clutches and the electric motor. Thanks to this arrangement, the transmission element according to the invention can adapt, to a conventional mono-source traction chain, and replace a simple clutch, to form a traction chain of the parallel hydride type, without modification. major of the other elements of the traction chain. is still

other optional features of the invention: - the first half-shell is integral with the stator and rotatably supports the rotor; - The housing is closed in a sealed manner to a lubrication and / or cooling fluid; the second clutch is returned to the engaged position; the first clutch is returned to the disengaged position; and - the dog clutch is provided with a synchronization device. The invention also relates to a motor vehicle comprising a traction chain of the parallel hydride type, said traction chain comprising a heat engine, ^" a gearbox, and a transmission element as described above, connecting the heat engine to the gearbox. of speeds. ^Modes' embodiment of the invention of particular will now be described in more detail with reference to Figures 2 and 3 of the accompanying drawings, in which: - Figure 2 is a partial view in axial section of a transmission element according a first, embodiment of the invention; and - Figure 3 is a similar view of a transmission element according to a second embodiment of the invention. . In Figure 2, there is shown a transmission element 25 according to a first embodiment of the invention, intended to connect, like element 5 in Figure 1, a heat engine to a gearbox. Like element 5, element 25 of the invention comprises an electric motor 31, a first clutch 33, and a second clutch 35. The transmission element 25 further comprises a motion input shaft 37 and a motion output shaft 39 coaxial X axis. The X axis is oriented from the input to the output for the convenience of the following description. The terms “upstream” and “downstream” will be understood with reference to this orientation. The input shaft 37 is integral in rotation with the crankshaft of the heat engine, part of which, or “nose”, is shown in FIG. 2 under the reference 41. In the example shown, the crankshaft 41 is provided with a flywheel 43, and connected to the input shaft 37 by means of a damping device 45. The output shaft 39 is linked in rotation to the primary gearbox input shaft , part of which is shown in Figure 2 under reference 47. The transmission element 25 comprises a casing essentially consisting of a first half-shell 51 and a second half-shell 52, assembled by fixing means' 54 distributed over the periphery of the casing. The casing half-shells 51, 52 internally delimit a housing 53, inside which the electric motor 31, the clutches 33, 35 and the input shafts 37 and output 39 are arranged coaxially. The input shaft 37 and the output shaft 39 are rotatably mounted relative to the housing 51, 52. The input shaft 37 is a splined shaft complementary to a hollow shaft 55 of the damping device 45, and a end portion of the input shaft ^'37 is axially projecting from the first half-shell 51 outwardly. The input shaft 37 is rotatably mounted on the first half-shell 51 by means of rolling bearings 57. The output shaft 39 is a hollow shaft with internal grooves, of shape complementary to the end of gearbox input shaft 47. To be engaged with the output shaft 39, the end of the gearbox input shaft 47 projects inside the housing 53. The electric motor 31 includes a stator 61 secured to the first casing half-shell 51, a manifold 62 secured to the stator, and a rotor 63 rotatably mounted on the first half-shell 51 by means of a bearing 65. • The rotor 63 is arranged radially inside the stator 61. The input shaft 37 is formed, preferably in one piece, with a radial wall, 95 which extends inside the housing 53, and which has a ring at the periphery axial 97. Correspondingly, the output shaft 39 is formed, preferably in one piece, a with a radial wall 105 which extends inside the housing 53, and which has on the periphery an axial ring 107. The axial ring 107 extends coaxially and radially outside relative to the ring 97. The first clutch 33 is arranged between the axial rings 97 and 107. The transmission element 25 further comprises a first piston 111 for actuating the first clutch 33, and a spring member 115 urging the first piston 111 under pressure on the first clutch 33. The first clutch 33 essentially consists of a first series of discs 121, linked in rotation to the crown 97 and axially displaceable on the latter under the effect of the piston 111, and a second series of discs 122, linked in rotation to the crown 107 and axially displaceable on the latter. The first 121 and second 122 discs are nested alternately. The discs 121, 122 are stopped axially by a stop 123 opposite the piston 111. It is understood that the discs 121, 122 can pass from a disengaged position, in which the first discs 121 do not make contact with the second discs 122, with a engaged position, in which the first 121 and second 122 discs are pressed against each other. In the disengaged position, the input shaft 37 and the output shaft 39 are free to rotate relative to each other. The spring member 115 consists, in the example shown, of a spring washer, of the Belleville washer type for example, and biases the piston 111 in the engaged position. The second clutch 35 comprises a pair of wheels 131, 132 coaxial with axis X, with axial dog-teeth susceptible of mutual engagement. The first claw wheel 131, linked in rotation to the rotor 63, is capable of axial displacement against a spring 137, under the effect of a second piston 141. The second piston 141 is linked in rotation to the 'output shaft 39 by a finger 142 passing through the radial wall 105. The spring 137 biases the claw wheel 131 towards the wheel 132, in the position of mutual engagement of the claws 133, 134, that is to say in position engaged by the clutch 35. Also under the return effect of the spring 137, the wheel 131 is permanently supported, by a peripheral edge projecting axially, on the piston 141. The clutch 35 is further provided with a synchronization device 145 consisting essentially, in known manner, of two complementary parts 146, 147 having respective axial frustoconical surfaces 148, 149 which can cooperate by friction. A first 146 of these parts is secured to the first claw wheel 131, while the second 147 of these parts is secured to the second claw wheel 132. During a phase of mutual engagement of the claws 133, 134, the frustoconical complementary surfaces 148, -149 engage mutually in friction, so that the claw wheels 131, 132 are gradually brought to the same speed of rotation, before positive engagement of the claws 133, 134. We will now describe the arrangements allowing moving the pressure pistons (or plates) 111, 141, and thus passing the clutches 33, 35 from one position to another among their engaged and disengaged positions. The second casing shell 52 is formed with two control fluid supply channels 151, 152, connected to a control fluid circuit (not shown). The first supply channel 151 opens into a first chamber, pressure 201, tight control fluid, formed between the first piston 111 and the ^radial wall 105. It is understood that the _fluid supply control under pressure this first chamber 201 via the first channel 151 causes the displacement of the piston 111 upstream, against the reaction of the spring 115. This displacement of the piston 111 causes the stacks of discs 121, 122 to be tightened, and the passage to the engaged position of the first clutch 35. When the control fluid is discharged from the first pressure chamber 201, via the same supply channel 151, the piston 111 moves downstream under the effect of the spring 115 , by loosening the disc stacks 121, 122. The clutch 33 then resumes its position called "naturally open", that is to say disengaged, in the absence of supply of the pressure chamber 201 with ordered. Similarly, the second supply channel 152. opens into a second pressure chamber 202, impermeable to the control fluid, formed between the piston 141 and a radial wall 205, integral with the output shaft 39 and axially spaced from the radial wall 105. It is understood that the supply of pressurized control fluid to the second chamber 202 causes the axial displacement upstream of the piston 141. Thus, the piston 141 integrally moves the wheel 131 upstream, at against the reaction of spring 137, so that the claws 133, 134 move from an initial position of mutual engagement in ^a disengaged position. When the supply of pressurized fluid to the second chamber 202 is interrupted and the fluid therein is discharged via the same channel 152, the claw wheel 131 returns to its initial position, in which the claws -133, 134 are in mutual engagement, under the effect of the spring 137. The second clutch 35 then resumes its so-called “naturally closed” position, that is to say engaged, in the absence of supply of the pressure chamber 202 with control fluid. The transmission element 25 operates ^" , as can be understood from the above, in the following way: - First case: the pressure chambers 201, 202 are not supplied The first clutch 33 is open, while the second clutch 35 is - closed, so that the heat engine does not supply power to the wheel shaft, and the electric machine 31 supplies power to, or receives power to, the wheel shaft (the accumulator) of electric energy. We are then in a "pure electric" operating mode. - Second case: the two pressure chambers 201, 202 are supplied The first clutch 33 is closed, while the second clutch 35 is open, so that only the heat engine supplies power to the wheel shaft, the electric machine 31 being mechanically isolated, and we are then in a "pure thermal" operating mode. cha pressure valve 201 is supplied and the second pressure chamber 202 is not supplied. The two clutches 33, 35 are in the closed position, so that the heat engine supplies power to the wheel shaft, and the electric machine 31 also supplies it, or collects it for recharging. electrical source. We are then in a “hybrid” operating mode. - Fourth case ^' : the first pressure chamber

201 is not supplied and the second pressure chamber

202 is powered The two clutches 33, 35 are then in the open position, so that neither the heat engine nor the electric machine 31 supply (or take away with regard to the electric machine), mechanical energy to one wheel shaft . In Figure 3, there is shown an alternative embodiment of the invention, which essentially differs from the embodiment shown in Figure 2 in that the second clutch 35 is devoid of synchronization device. In this exemplary embodiment, the dogs 333, 334 are formed directly on the one hand on the piston 141, and on the other hand on a part integral with the rotor. In the example shown, the dogs 333, 334 are formed of radial teeth, or _. frontal type. When the dogs 333, 334 are mutually engaged, as illustrated in FIG. 3, the rotor 63 and the output shaft 39 are linked in rotation by means of the piston 141. A displacement downstream of the piston 141, at from the position shown, causes the dogs 333, 334 to disengage, and thus release the rotational connection of the rotor 63 and the output shaft 39.

Claims

CLAIMS 1. Transmission element for a parallel hybrid type traction chain, said element (25) comprising a motion input shaft (37) intended to be connected to a heat engine, an output shaft (39) movement intended to be connected to a gearbox, an electric motor (31) comprising a stator (61) and a rotor

(63), a first clutch (-33) connecting between the input shaft (37) and the output shaft (39), and a second clutch (35) connecting between the rotor (63) and the 'output shaft (39), one (33) of said clutches being of the wet friction type, characterized in that the other (35) of said clutches is of the dog clutch type.

2. Transmission element according to claim 1, characterized in that the first clutch (33) is of the wet friction type, and the second clutch (35) is of the dog clutch type.

3. Transmission element according to claim 1 or 2, characterized in that the two clutches (33, 35) are arranged radially inside the electric motor (31). . ^'

4. Transmission element according to any one of claims 1 to 3, characterized in that ^'it comprises a, housing having a first half-shell (51) rotatably supporting the input shaft (37), and a second half-shell (52) rotationally supporting the output shaft (39), these two half-shells (51, 52) defining a housing (53) in which the two clutches (33, 35) are mounted coaxially and the electric motor (31).

5. Transmission element according to any one of claims 1 to 4, characterized in that the first half-shell (51) is integral with the stator (61) and rotatably supports the rotor (63).

6. Transmission element according to any one of claims 1 to 5, oaractérisé in that the housing (53) is closed in a sealed manner to a lubricating and / or cooling fluid.

7. Transmission element according to any one of claims 1 to 6, characterized in that the second clutch (35) is returned to the engaged position.

8. Transmission element according to any one of claims 1 to 7, characterized in that the first clutch (33) is returned to the disengaged position.

9. Transmission element according to any one of claims 1 to 8, characterized in that the dog clutch (35) is provided with a synchronization device (45).

10. Motor vehicle comprising a parallel hydride type traction chain, said traction chain comprising a heat engine (3), a gearbox (7), and a transmission element (25) according to any one of claims 1 to 9 connecting the heat engine (3) to the gearbox (7).