FR3077109A1 - INFINITELY VARIABLE TRANSMISSION WITH POWER DIVIDER TRAIN AND METHOD OF OPERATING THE SAME - Google Patents

Abstract

Infinitely variable transmission (1) with epicyclic gear train (30) power divider which mechanically connects a heat engine and two electrical machines (60, 70) exchanging electrical power with each other, transmission in which the mechanical power of the engine is distributed over a level of an input element of the train between a first power channel where it is taken by a first electrical machine (60), and a second power channel, where it is connected to the mechanical power of the second electric machine ( 70), and is grouped on an output element of the train from which it is transmitted to the wheels of the vehicle on a variable transmission ratio depending on the electrical power exchanged between the two electrical machines, characterized in that it comprises a coupling group (40) which can occupy three positions in which: - the coupling group (40) is open, - the coupling group (40) is t closed and the sun gear (35) of the epicyclic gear (30) is locked in rotation, and - the coupling group (40) is closed and the epicyclic gear (30) rotates in a block.

Description

INFINITELY VARIABLE TRANSMISSION WITH A DIVIDING TRAIN

POWER AND OPERATING METHOD THEREOF

The present invention relates to variable speed drives, or infinitely variable transmissions

CVT for "

Continuously Variable Transmission ”in which the ratio between the speed of entry and the speed of exit, varies continuously.

More specifically, it relates to an infinitely variable transmission planetary power divider train, which mechanically connects a heat engine and two electric machines exchanging electric power between them.

In this transmission, the mechanical power of the heat engine is distributed at the level of an input element of the train, between a first power track, where it is taken up by a first electric machine, and a second power track, where it is combined with the mechanical power of the second electric machine. The power gathers on an output element of the train, from where it is transmitted to the wheels of the vehicle on a variable transmission ratio according to the electric power exchanged between the two electric machines.

In variators based on a planetary gear train, the ratio is adjusted by imposing a speed differential between two elements of the train. When the rotation speed of a component of the train is varied, the reduction ratio between two other elements varies accordingly.

By publication EP 1 125 780, a hybrid kinematic chain known as e-CVT is known, comprising a heat engine and a transmission based on a planetary gear train, using two electric machines GEN and ME, to vary its transmission ratio. The heat engine is connected to the planet carrier of the train. A first GEN electric machine is connected to the planet. By varying its speed, the ratio between the heat engine and the wheels, which are connected to the crown, as well as to the second electric machine ME, is varied. By varying the speed of the first GEN electric machine, the transmission ratio between the heat engine and the wheels is varied.

In the case of a conventional vehicle, all the energy supplied to the wheels comes from the heat engine. The main role of the e-CVT is to adjust the ratio between the engine and the wheels. In the sectional drawing of Figure 1, the GEN machine can take mechanical power from the ICE heat engine, or provide mechanical power (and therefore produce or consume power), depending on how it is controlled. The second machine ME is then used to expend or produce this electrical energy, while remaining at zero energy balance (no storage or electrical expenditure). In the case of a hybrid vehicle, the machine provides electric driving and energy recovery under braking

The efficiency of the e-CVT depends on its reduction ratio.

According to this ratio, the electrical power exchanged between the machines varies to the extreme, where all the mechanical power supplied by the heat engine goes into electrical bypass.

If the GEN machine is not running, the transmission bypass rate is

The transmission therefore places the system on a point of very good performance. The transmission is at its maximum efficiency, because no mechanical power is taken or supplied by the GEN machine. However, it must provide the support torque necessary to balance the train.

When all the train components rotate at the same speed, the mechanical efficiency is also maximum.

But in this case, the GEN machine takes power, because it rotates, and provides a support torque proportional to the torque of the engine.

The present invention aims to relieve the electric machine, of the support torque to be provided to maintain the balance of the train, when circumstances allow.

To this end, it plans to integrate into the transmission a coupling group which can occupy three positions in which it is respectively:

Open,

Closed, so as to block the planetary gear train from rotating, and

Closed, so as to rotate the train as a whole.

In the second position, the electric machine does not rotate, in the third, it rotates: in both cases the blocking system relieves it of the support torque, and eliminates any derivation of power. The transmission is on a fixed gear ratio, vis-à-vis the engine.

The transmission thus has:

- a first operating mode, where the coupling group is open: the power derived on the first electric machine then varies according to the speed of the heat engine,

- a second operating mode, where the coupling system is closed by blocking the sun gear: all of the power of the heat engine is then found on the output gear of the train, and a third operating mode, where the coupling system is closed on the planet carrier: all of the heat engine's power is then found on the gear output crown.

The present invention will be better understood on reading the following description of a non-limiting embodiment thereof, with reference to the appended drawings, in which:

FIG. 1 is the longitudinal section A-A of the electric e-CVT type transmission;

Figure 2 a simplified cross section;

Figure 3 is a partial enlargement of Figure 1, the freewheel of the planetary gear area and the locking device;

Figure 4 is a partial view of Figure 1, illustrating the power flow in the planetary gear in power bypass mode;

FIG. 5 is a partial view of FIG. 1, illustrating the power flow in the planetary gear in blocked planetary gear mode (long fixed ratio);

FIG. 6 is a partial view of FIG. 1, illustrating the flow of power in the planetary gear in blocked planetary gear mode (short fixed ratio);

Figure 7 is a view illustrating the flow of power in electric mode, the generator resting on the freewheel.

Nomenclature

I. Transmission assembly

10. Flywheel housing

II. Mechanism housing. Control mechanism support

13. Cover of electrical machines

20. Crankshaft nose

21. Flywheel

22. Torque limiting coupling friction

23. Vibration damper

30. Planetary train

31. Satellite carrier

31, s. Planet carrier shaft

31. b. Inner track of pebbles

32. Satellite axis (3)

33. satellite (3)

34. Inner gear crown

34, a. Outer gear crown

35. Planetary gear

40. Locking device

41. Hub

42. Walkman

43. Dog clutch cone on satellite carrier

44. Claw cone on support of the control mechanism

45. Synchro ring

46. Arming key

47. Control fork

48. Fork axis

50. Freewheel

51. Pebbles

52. Intermediate ring

52, a Roller track

52, b. Outer cone

53. Notched outer ring of the freewheel

53, a Inner cone

53. b. Peripheral notches

54. Preload washer

55. Stop ring

60. GEN electric machine

61. GEN stator

61, s. Sheet pack

61, b. Winding

62. GEN rotor

62, s. Sheet pack

62, b. Winding

62. c. GEN rotor axis

63. Supply collector

64. GEN speed sensor

70. ME electric machine

71. ME stator

71, a. Sheet pack

71, b. Winding

72. Rotor ME

72, s. Sheet pack

72. b. Winding

73. Supply collector

74. ME speed sensor

80. ME tree

81. Descent pinion to secondary shaft

90. Secondary tree

91. Lowering pinion to differential crown

92. Common pinion for lowering ME and the planetary gear

100. Differential assembly

101. Differential housing

102. Planetary and differential satellites

103. Differential crown

Description

The classic e-CVT system illustrated in FIG. 1, is composed of four main elements: a planetary gear train 30, which mechanically connects a first GEN 60 electric machine, a second ME 70 electric machine and an ICE 20 heat engine, which is the main source of power. The GEN 60 electric machine makes it possible to adapt the reduction ratio between the heat engine and the wheels. The ME 70 electric machine is permanently linked to the wheels, in a fixed ratio.

This transmission is infinitely variable. The two electric machines 60, 70 exchange electrical power between them. The planetary gear 30 divides the mechanical power of the heat engine. It is distributed at the level of an input element 31 of the train (satellites 33), between a first power channel where it is taken by the first electric machine 60, and a second power channel, where it is connected to the mechanical power of the second electric machine 70. The power gathers on an output element of the train, from where it is transmitted to the wheels of the vehicle on a variable transmission ratio according to the electric power exchanged between the two electric machines.

In the nonlimiting embodiment of

The invention illustrated by the figures, the heat engine is connected to the planet carrier of the train

31. The first GEN electric machine, 60, is connected to the planet

35, and the second electric machine

ME, 70, is connected to the output crown. In the figures, we can see from right to left, a flywheel and differential housing

10, the mechanism housing 11, the control mechanism support 12 and the housing of electrical machines 13 of the transmission.

In the first casing 10, we see the crankshaft 20, a conventional flywheel 21 of a heat engine (not shown), a torque limiter 22, and a damper 23.

The mechanism housing 11 contains the epicyclic power dividing train 30, with the coupling group 40, which are enlarged in FIG. 3. The epicyclic power dividing train 30 is composed of a sun gear 35, of a satellite carrier 31, and a crown 34. In this nonlimiting embodiment, the sun gear 35 is connected to the electric machine GEN 60. The planet carrier 31 is linked to the heat engine, represented by its crankshaft 20, via of the shaft 31, a and of the shock absorber 23. The crown of the train 34, a is connected to the wheels of the vehicle by two stages of pairs of pinions.

The transmission comprises a coupling group 40 which can occupy three positions in which:

- he is open, - the planetary 35 of train 30 East blocked in rotation, and - the train 30 turns in block. The coupling group 40 is composed of a hub 41 supported through the generator shaft 62, c. II is surrounded a sleeve doggy 42 sliding axi also on

this one. The sleeve 42 can adopt a central position and two extreme positions on the right and on the left:

in the center, the planetary gear 35 transfers part of the power of the heat engine to the first electric machine 60, depending on the speed of the heat engine, in the first axial offset position (left), the coupling group 40 connects the planetary 35 at a fixed point of the transmission, and blocks planetary 35

in rotation ; the sleeve 42 is engaged in first a dog 44 supported by the support of its mechanism of command 12; in the second position of offset axial, the coupling group 40 binds the planetary 35 and The door- satellites of train 31, so that make turn this

last of a single block; the sleeve 42 is engaged in a second dog 43, fixed on the planet carrier 31.

- 8 The movements of the clutch sleeve are ensured by a control comprising a fork 47 supported by a pin 48 itself supported by the mechanism housing 11 and the support 12 of the control mechanism. Its movements are controlled by a linear actuator (pneumatic, hydraulic, or electric), not shown. In the latter case, it is connected to the existing power supply network. The sleeve 42 engages in its extreme positions inside the dogs 43, 44, on the right and on the left. The first (right clutch dog 43) is supported by the satellite carrier 31; the second dog (left dog 44) is fixed on the mechanism support 12. To avoid noisy phenomena such as “cracking”, the coupling group 40 comprises a synchronization ring 45 placed in position by the arming keys 46.

When the engine is stopped (running in electric mode) it no longer provides support for the train 30. A freewheel 50 takes over. It then allows the generator 60 to be used as an engine for driving in electric mode, but only in forward gear.

The total or partial power transmitted to the crown of the train is transmitted to the secondary shaft 90 by a pair of pinions 34, a and 92. The power of the ME 70 is transmitted to the shaft 80, then is also transmitted to the secondary shaft 90 by the pair of pinions 81 and 92. The powers coming from the electric machine 70 and the planetary gear end up on the same pinion 92. Finally, the power is transmitted to the wheels, from the secondary shaft 90 by the pinion 91 to the crown gear 103 which is part of a differential assembly 100 comprising a housing 101, which supports the crown 103, and contains a mechanism 102 for distributing torque to conventional wheels, planetary and satellites.

When the group is declutched (Figure 4), the train 30 operates in power bypass. Transmission is in e-CVT mode. The power of the heat engine enters through the planet carrier 31. The power distribution is carried out at the level of the satellites 33. It is shared between the sun gear 35 for the power drawn by the generator 60, and the crown 34, for the power transmitted directly to the wheels. The power circulation is represented by the solid arrowed lines, and the direction of circulation is valid for the direction of driving of the vehicle by the heat engine.

Like all epicyclic trains, the dividing train 30 obeys laws, the main ones of which are:

• zero power sum (incoming power = outgoing power), • torque at the planet carrier = torque at the planet wheel + torque at the crown.

As a function of the speeds of the crown 34 (that is to say of the vehicle) and of the heat engine (the optimum operating point of which is chosen for each given situation), the speed of the generator 60 is imposed, and the power drawn off, or "derivative", is fixed. For a given vehicle speed, the engine can be stalled at any speed, thanks to the variable power bypass. When the vehicle is started, it can thus be in a series hybrid operating mode, where the derived power is close to 100%. On the other hand, at high speed, if the derived power is close to 0%, the operation of the vehicle is that of a parallel hybrid vehicle.

In Figure 5, the system is clutched to the left. The sleeve 42 is engaged on the dog 44, linked to the support of the control mechanism 12. The sun gear 35 and the generator 60 are blocked. The support torque is provided by the dog clutch 44. The speed being zero, the power exchanged is zero. The transfer of the support torque between the dog clutch 44 and the sun gear 35 is indicated in non-arrowed lines, while the circulation of power between the heat engine and the crown 34 is indicated in arrowed lines, in the vehicle driving situation by the engine. All the power of the heat engine is then transmitted to the crown of the train 34 and to the wheels. The derivation of electrical power is zero. The reduction between the heat engine and the wheels is long because the transmission of power from the planet carrier 31 to the crown 34 is overdriven according to the ratio (Nc + Np) / Ne. Ne is the number of teeth of the crown and Np the number of teeth of the planetary. This report can only be used at rather high speed, for example on the motorway. The traction machine 70, being always connected to the wheels, turns quickly at zero load. In this arrangement, the permanent magnet machines "deflux" and "drag", unnecessarily, significantly. Hence the advantage of associating with this transmission a machine with a wound rotor, which has only a residual drag of the own bearings, due to

the absence of field magnetic created at the request. In variant we could put one dog sure the motor so further optimize performance and born not suffer her

mechanical drag.

In FIG. 6, the system 40 is clutched to the right. The sleeve 42 is engaged on the dog clutch 43, linked to the satellite carrier 31. The planetary gear 35 and the planet carrier 31 being linked, the planetary gear 30 rotates in one piece. The support torque of the sun gear 35 is provided by the dog clutch 43. The power taken from the planet carrier 31 is transmitted to the sun gear 35, and fully restored. Under these conditions, all the power of the heat engine is transmitted to the crown of the train 34 and to the wheels. The direction of power flow indicated corresponds to the situation in which the vehicle is driven by the heat engine. The electrical power bypass is zero, the generator 60 rotates freely, but does not provide torque. The reduction between the heat engine and the wheels is "short", because the power transmission, from the satellite carriers 31 to the crown 34, is in the ratio 1. This configuration can only be used at a rather high speed, and all particularly on roads, expressways or motorways, for example, in a gradient. The generator 60, rotates at the speed of the thermal engine at zero load. Under these conditions of use, a generator with permanent magnets, "defluxes", and "drags" unnecessarily. Hence the interest of associating with this transmission a generator with a wound rotor, because this type of generator has only a residual drag on its own bearings, due to the absence of magnetic field created on demand.

Figure 7 illustrates taxiing in electric mode, in forward gear. The heat engine 20 is stopped. It is not able to bring the support torque to the satellite carriers 31. In this situation, the freewheel 50 intervenes, taking over from the heat engine. It prevents the latter from turning upside down and provides the support torque while driving the planet carrier. The power supplied by the generator 60 to the sun gear 35, is fully transmitted to the crown 34. By the toothing 34, a of the latter, it passes to the down pinion 92 common with the pinion 81 for transmitting power from the power train 70 The planet carrier 31 is supported on the freewheel 50. The power circulation for driving the vehicle by the two electric machines 60 and 70 is represented by two arrowed lines. The non-arrowed lines between the freewheel and the axes of the satellites 32 represent a support torque (zero power).

In summary, in the central position of the coupling group 40, the planetary gear operates freely in eCVT. In a first axial offset position, it connects the sun gear to a fixed point, and blocks the sun gear in rotation. The transmission is on a first “long” fixed gear. In a second axial offset position, it links the sun gear 35 and the planet carrier allowing the train to turn in one piece. The transmission is on a second “short” fixed gear.

Thanks to the three-position coupling device 40, the transmission has:

• a first operating mode, in which the coupling group 40 is open, where the power derived from the first electric machine 60 varies as a function of the engine speed.

• a second operating mode, in which the coupling system 40 is closed by blocking the sun gear 35, where all of the power of the heat engine is found on the gear output crown 34: the first GEN machine does not rotate not, and the support torque is provided by the coupling system: the derived electrical power is zero. The entire power of the heat engine is found on the output gear of the train according to a "long" reduction;

• a third operating mode, in which the coupling system is closed on the satellite carriers 31, where all of the power of the heat engine is found on the output crown of the train 34: the first GEN machine rotates at speed of the blocking train but without providing torque; the derived electrical power is zero.

Thanks to the freewheel, the transmission also has an electric drive mode in the forward direction, where the two machines provide power in tandem.

The choice to switch to one or other of the fixed gears can be made from a map indicating whether it is interesting to switch there from an energy point of view, depending on the speed of the vehicle and the power requested from the wheel.

In the first situation, the generator is blocked, but the motor rotor is still connected to the wheels. It rotates, and consumes energy unnecessarily by the appearance of a drag by "defluxing" if it is with permanent magnets. In the blocked train situation, the two machines rotate, so that the "defluxing" trails are increased.

The present invention proposes to improve the efficiency of this hybrid transmission on this aspect, by combining the blocking system of the generator and the train and with a motor and a generator with wound rotor.

To switch from e-CVT mode to one or other of the fixed ratios, the heat engine and the generator are controlled to establish the ratio of the planetary fixed ratio, before carrying out the satellite carrier, coupling. Since the coupling of either with the support preparation of in e-CVT mode, or with the mechanism of the dog clutch is carried out in approach by piloting the generator, the passage on the fixed ratio is soft and imperceptible, because there There is no variation in the vehicle's acceleration level. The choice to switch to one or other of the fixed ratios of the transmission, can be made from a map indicating whether it is interesting, from an energy point of view, to switch there according to the vehicle speed and the power required by the wheel.

The advantages of the invention are numerous. Among these, the following points should be emphasized:

• the dog clutch gives two discrete reports allowing two modes of parallel hybrid driving, improving the efficiency of the transmission, • when traveling on discrete fixed reports, the two machines with wound rotor minimize losses because they do not deflux, • l 'absence of breakage or peak torque when activating and deactivating fixed gears, because it is not a gear change, and • the freewheel allows the use of the two electric machines in electric driving.

Claims (10)

1. Infinitely variable transmission (1) with planetary gear train (30) power divider which mechanically connects a heat engine and electrics (60, 70) exchanging between them electric, transmission in which mechanics of the heat engine is distributed two of the machines power power at the level of the input element of the train (33) between a first power track where it is taken up by a first electric machine (60), and a second power track, where it is combined with the mechanical power of the second electric machine (70), and is grouped together on an output element of the train from where it is transmitted to the wheels of the vehicle on a variable transmission ratio as a function of the electric power exchanged between the two electric machines, characterized in that that it includes a coupling group (40) which can occupy three positions in which the coupling group (40) is open, the coupling group (40) and st closed and the sun gear (35) of the train (30) is locked in rotation, and and the train 2. Transmission infinitely variable according to the claim 1, characterized by that the group of coupling (40) includes a hub (41) surrounded by muff of dog clutch (42) sliding axially on this one. 3. Transmission infinitely variable according to the is claim 2, characterized in that the first machine Infinitely variable transmission according to claim 2 or 3, characterized in that the sleeve slides axially over between a central position where the planetary gear transfers part of the power of the heat engine to a first axial offset position, depending on the speed of the heat engine. , where the coupling group (40) connects the sun gear (35) to a fixed point of the transmission, and blocks the planet wheel (35) in rotation, and a second axial offset position, where the coupling group (40) links the sun gear (35) and the satellite carriers of the train (31), so as to rotate the latter in one piece. 5. Infinitely variable transmission according to claim 4, characterized in that the sleeve (42) engages respectively in a first dog clutch (43) supported by the planet carrier (31) in a second dog clutch (44) fixed on the support of its control mechanism (12). 6. Infinitely variable transmission according to one of claims 2 to 5, characterized in that the coupling group (40) comprises at least one synchronization ring (45) held in position by arming keys (46). 7. Infinitely variable transmission according to one of claims 2 to 6, characterized in that the movements of the clutch sleeve (42) are ensured by a control comprising a fork (47) supported by an axis (48) itself supported by the mechanism housing (11) of the transmission (1) and by the support of the control mechanism (12). 8. Infinitely variable transmission according to one of claims 2 to 6, characterized in that the electrical machines (60, 70) are wound rotor machines. 9. Method of operating a transmission according to one of the preceding claims, characterized in that the transmission has a first operating mode, in which the coupling group open, where the power derived on the first machine varies depending on the engine speed. 10. Operating method according to claim 9, characterized in that the transmission has a second operating mode, in which the coupling system (40) is closed by blocking the sun gear (35), where all of the power of the heat engine is found on the crown (34) of the train outlet (30). 11. Operating method according to claim 9 or 10, characterized in that the transmission has a 5 third operating mode, in which the coupling system is closed on planet carrier (31), where all of the power of the heat engine is found on the gear output ring (34). 12. Operating method according to claim 10 9, 10 or 11, characterized in that the transmission has an electric driving mode in the forward direction, where the two machines (60, 80) supply the power in tandem.