Transmission for motor vehicle with hybrid propulsion or traction

Abstract

The invention relates to a transmission (1) for a hybrid traction or propulsion motor vehicle, said transmission (1) comprising: a first machine (20) comprising a rotor (22) fixed to a main power drive shaft (21), said main power drive shaft (21) rotating together with a main gearbox input shaft (25) configured to be coupled or decoupled with the wheels of the vehicle; a second machine (40) comprising a rotor (42) fixed to a secondary power drive shaft (41) that co-rotates with a gearbox input countershaft (45) configured to couple or decouple wheels of the vehicle; and an internal combustion engine fixed to the input shaft (60). The second electric machine (40) is connected to the wheels independently of the internal combustion engine.

Description

[0001] The invention relates to the field of transmissions for motor vehicles with hybrid propulsion or traction, which transmissions comprise a thermal-mechanical traction device on the one hand and an electrical traction device on the other hand.

[0002] More specifically, the invention relates to a hybrid transmission comprising an internal combustion engine, two electric drive machines and three main shafts, one main shaft being connected to the crankshaft of the internal combustion engine and the other two main shafts being connected to the electric machines. Each traction device is connected to its main shaft without a decoupling device.

[0003] Document FR 3 022 495 describes a hybrid transmission configured to transmit the power of a heat engine and two electric machines to the wheels of a motor vehicle. The heat engine, called the driving engine, and the main electric machine are both connected to a main shaft without decoupling devices. The two main shafts are coaxial and the shaft of the electric machine is concentric with the shaft of the heat engine. A second electric machine, called the generator, is offset transversely with respect to the crankshaft axis and is permanently connected to the main shaft connected to the heat engine by a series of gears.

[0004] The main electric machine is configured to be connected to the wheels of the vehicle in two different gear ratios by dog ​​engagement means without a synchronizing device. The heat engine is configured to be connected to the wheels of the vehicle in four different gear ratios using the same engagement means. Two engine gear ratios depend on the main electric machine gear ratio, and two gear ratios including the fourth gear ratio are dedicated to the heat engine.

[0005] The heat engine and the electric machine are attached to a gearbox. There is a spline drive and a dynamic seal between the gearbox and each electric machine. Compared with the heat engine, the generator has a very high rotation speed, making it difficult to ensure the reliability of the assembly due to its arrangement at altitude and without means of correction of coaxiality defects.

[0006] Each motor has its own water cooling system, which combined with the gearbox water cooling system results in three cooling systems to be managed. The Joule effect losses of the motor cannot be used directly to accelerate the temperature rise of the gearbox oil in the first few kilometers and thus improve its energy efficiency.

[0007] The generator is permanently connected to the heat engine. When driving in electric mode, especially in the case of a plug-in hybrid electric vehicle (PHEV), the generator cannot participate in traction of the vehicle. The main electric drive machine must then be dimensioned to operate only in electric mode.

[0008] Furthermore, the main motor is a so-called slow machine with two gear ratios, a so-called low gear ratio to ensure low-speed acceleration and a so-called high gear ratio to ensure top speed. During gear changes, the continuity of the torque at the wheels is supported by the generator, but is only partially guaranteed.

[0009] There is a need for improvements over prior art hybrid transmissions for motor vehicles.

[0010] It is therefore an object of the present invention to provide a hybrid transmission having improved energy performance.

[0011] a first main machine or motor including a rotor integral with a main power transmission shaft which rotates integrally with a main gearbox input shaft via a splined connection, the main gearbox input shaft being configured to be coupled or decoupled to a wheel of the vehicle via a first coupling system,

[0012] a second main machine or electric machine including a rotor integral with a second power transmission shaft, the second power transmission shaft rotating integrally with a secondary gearbox input shaft via a splined connection, the secondary gearbox input shaft being configured to be coupled or decoupled to a wheel of the vehicle via a second coupling system, and

[0013] A heat engine integral with the input shaft.

[0014] A second electric machine is connected to the wheels independently of the thermal engine.

[0015] Thus, when the powertrain is a plug-in hybrid, the generator can be used as a drive in electric mode. By supporting the traction machine, it reduces the size of the latter.

[0016] For example, the electric motor is integrated into a dedicated compartment of the gearbox at the end of the gearbox.

[0017] This makes it possible to envisage a common output for the three phases of each motor and the wiring of the resolver, and facilitates the mounting of the power electronics directly on the gearbox, with busbar connection and without wiring.

[0018] The electric motor preferably runs in oil. The transmission may include a single cooling system for the electric motor and the gearbox.

[0019] Thus, the losses due to the Joule effect of the electric machine are recovered to accelerate the heating of the oil, improving the efficiency of the transmission within the approval cycle and also when operating under real conditions of low load and short duration.

[0020] Furthermore, the seals can be removed, eliminating the associated losses.

[0021] Finally, the spline connection between the motor and the input shaft is lubricated with circulating oil.

[0022] Advantageously, the transmission comprises a first layshaft configured to be coupled or decoupled with the gearbox main shaft and a second layshaft configured to be coupled or decoupled with the gearbox layshaft.

[0023] The fact of having two secondary shafts allows for good compactness and better mechanical strength. The drive pinion is relocated at the end of the secondary shaft.

[0024] For example, the main gearbox shaft carries a single idler gear and the first countershaft carries a fixed pinion configured to mesh with the first idler gear and a toothing configured to mesh with a ring gear of a differential assembly.

[0025] For example, the first coupling system is carried by the gearbox shaft and comprises a hub and a sliding sleeve or a shift sleeve.

[0026] For example, the gearbox input layshaft carries two idler gears, the second layshaft carries a fixed pinion configured to mesh with a first intermediate pinion, the first intermediate pinion is carried by the intermediate shaft and configured to mesh with a first idler gear of the gearbox input layshaft, the second layshaft also carries a toothed portion configured to mesh with a ring gear of the differential assembly.

[0027] For example, the second coupling system is carried by the gearbox shaft and comprises a hub and a sliding sleeve or a shift sleeve.

[0028] For example, the thermal engine input shaft carries a fixed pinion configured to mesh with a second idler gear of the gearbox input layshaft.

[0029] A pair of connecting pinions between the generator and the heat engine are integrated into the axial space of the ring gear.

[0030] Advantageously, the transmission has a plurality of gear ratios for the thermal engine independently of the electrical machine, which allows operation in thermal mode in all gear ratios alone.

[0031] For example, the input shaft of the heat engine carries five fixed pinions, namely, a pinion corresponding to the second gear transmission ratio, a pinion corresponding to the first gear transmission ratio, a pinion corresponding to the third gear transmission ratio, a pinion corresponding to the fourth gear transmission ratio, and a pinion corresponding to the driving pinion of the heat engine through the auxiliary motor. The fixed pinions of the first gear transmission ratio and the third gear transmission ratio are configured to respectively mesh with the idler pinions carried by the first auxiliary shaft, and the fixed pinions of the second gear transmission ratio and the fourth gear transmission ratio are configured to respectively mesh with the idler pinions carried by the second auxiliary shaft.

[0032] Advantageously, the transmission further comprises a parking brake device comprising a toothed wheel, the axial position of the toothed wheel being located on an axial edge of the ring gear of the differential assembly.

[0033] For example, the toothed wheel is located on the gearbox input main shaft of the main motor and is integrated into the axial space of the ring gear.

[0034] Advantageously, the main electrical machine is offset from the axis of the crankshaft of the thermal engine, which results in the elimination of a hollow shaft.

[0035] For example, the traction machine was selected as a fast type capable of reaching 15,000 rpm, which eliminates the problem of shifting gear ratios, and is configured for disconnection.

[0036] According to a second aspect, the invention relates to a motor vehicle with hybrid propulsion or traction, comprising at least two drive machines and a transmission as described above, configured to drive the drive machines in rotation.

[0037] Other objects, features and advantages of the present invention will become apparent from a reading of the following description given by way of non-limiting example only and with reference to the accompanying drawings, in which:

[0038] Figure 1 A schematic transverse view showing a transmission of a motor vehicle according to an embodiment of the invention;

[0039] Figure 2 yes Figure 1 A longitudinal section II-II of the transmission, which passes through the main machine, the auxiliary machine, the layshaft and the differential;

[0040] Figure 3 yes Figure 2 III-III, a cross-sectional view of a ring gear of a transmission;

[0041] Figure 4 Shows the motor to Figure 2 The power path to the wheels of the transmission;

[0042] Figure 5 Indicates that under the first gear ratio and the third gear ratio, the heat engine reaches Figure 2 The power path to the wheels of the transmission;

[0043] Figure 6 It shows that in the second gear ratio and the fourth gear ratio, the heat engine Figure 2 the power path of the transmission to the wheels; and

[0044] Figure 7 The power path between the heat engine and the secondary generator is shown.

[0045] like Figure 1 As shown very schematically in FIG. 1 , a powertrain or transmission (referenced generally at 1 ) is intended to be integrated into a motor vehicle (not shown) having hybrid propulsion or traction.

[0046] The powertrain 1 comprises two electric machines 20, 40, each intended to drive a drive shaft (not shown) of the drive wheels of the vehicle via a differential assembly 100. The electric machines 20, 40 each comprise their own power transmission path.

[0047] The power system 1 also comprises a heat engine, represented by its input shaft 60 .

[0048] Each power source is connected to an input shaft. A main machine 20 , referred to as a drive machine, is connected to the input shaft 25 . An auxiliary traction motor 40 , referred to as a generator, is connected to the input shaft 45 .

[0049] There is no decoupling device between the power source and the input shaft 25 , 45 , 60 .

[0050] All power sources are configured to be connected to the wheels of the vehicle via shafts, pinions, and coupling devices in one or more gear ratios.

[0051] As shown in the figure, the power system 1 includes three separate housings 10 , 11 , 12 , namely a flywheel housing 10 , a mechanism housing 11 and a motor housing 12 .

[0052] The flywheel housing 10 contains a flywheel (not shown) of the heat engine.

[0053] The flywheel housing 10 and the mechanism housing 11 define between them a first compartment (not shown) in which all mechanical components, such as in particular the power transmission, the coupling system, the mechanism for engaging the parking brake, etc., are mounted.

[0054] The mechanism housing 11 and the motor housing 12 define a second compartment (not shown) therebetween, wherein the two motors 20 , 40 are mounted in the second compartment.

[0055] The two compartments are not watertight relative to one another. The fluid used to lubricate and cool the bearings and the bearings of the pinion therefore corresponds to the cooling fluid of the electric machine 20 , 40 .

[0056] The heating and cooling fluids are thus shared, thereby having a single exchange and regulation system. The main advantage of this sharing is the direct and therefore more efficient use of the heat dissipated by the electric machine to quickly heat the lubricating fluid after starting the engine and over short distances. The efficiency of the mechanical components of the transmission is thus improved.

[0057] The first electric machine 20 or main machine, called drive machine, comprises a shaft 21 supporting a rotor 22 and a stator 23. Thanks to speed and angular position sensors 24, control of this electric machine is possible.

[0058] The rotor shaft 21 is rotatably fixed to the main gearbox input shaft 25 by a spline connection 29. The two shafts 21, 25 are supported by three bearings 26, 27, 28. The first bearing 26 is installed in the intermediate housing 11, the second bearing 27 is installed in the motor housing 12 and supports the rotor shaft 21, and the third bearing 28 is installed in the flywheel housing 10.

[0059] The main gearbox input shaft 25 is supported on the one hand by a third bearing 28 and on the other hand by the rotor shaft 21 via a centering and guiding area 29 a juxtaposed with the spline 29 .

[0060] The gearbox shaft 25 carries a single idler gear 30 and a first coupling system consisting of a hub 31 and a sliding sleeve 32 or shift sleeve.

[0061] The transmission 1 further comprises a parking brake device comprising a toothed wheel 33 arranged close to the third bearing 28 and close to the engaging surfaces of the housing of the flywheel 10 and the intermediate body 11. Figure 3 As shown, the axial position of the parking wheel 33 is inscribed at the axial edge of the ring gear 102 of the differential assembly 100 .

[0062] The displacement of the sleeve 32 allows the gearbox input shaft 25 to be coupled with the pinion 30. The pinion 30 meshes with a fixed pinion 82 carried by a layshaft 80, referred to as a high shaft. The layshaft 80 has teeth 81 at its opposite end that mesh with a ring gear 102 carried by a differential case 101 of the differential assembly 100. Figure 4 It can be seen from the power transmission path shown by the dotted line that the double mesh 30, 82 and 81, 102 constitute the only connection between the main machine 20 and the wheels.

[0063] The second electric machine 40 or auxiliary machine, called generator, comprises a shaft 41 supporting a rotor 42 and a stator 43. Thanks to speed and angular position sensors 44, it is possible to control this electric machine.

[0064] The rotor shaft 41 is rotatably fixed to the gearbox input layshaft 45 by a spline connection 49. The two shafts 41, 45 are supported by three bearings 46, 47, 48. The first bearing 46 is mounted in the intermediate housing 11, the second bearing 47 is mounted in the motor housing 12, and the third bearing 48 is mounted in the flywheel housing 10 and supports the gearbox input layshaft 45.

[0065] The rotor shaft 41 is supported on the one hand by a second bearing 47 and on the other hand by the gearbox input layshaft 45 via a centering and guiding area 49 a juxtaposed with the spline 49 .

[0066] The gearbox input layshaft 45 carries two idler gears 50, 51 and a second coupling system consisting of a hub 52 and a sliding sleeve 53 or a shift sleeve. The gearbox input layshaft 45 is coupled to the idler gear 50 by moving the sleeve 53 to the left, i.e. towards the electric machine 40. This gear 50 meshes with an intermediate pinion 71 mounted on a needle bearing 72 and carried by an intermediate shaft 70. This shaft 70 is fixed in rotation by an anti-rotation pin 73. The intermediate pinion 71 meshes with a fixed pinion 92 carried by a so-called low layshaft 90. Said shaft 90 comprises at its opposite end a toothing 91 which meshes with a ring gear 102. As Figure 4 It can be seen from the power transmission path shown by the solid line that the triple meshing 50, 71 then 71, 92 and 91, 102 constitutes the only connection between the auxiliary motor 40 and the wheels.

[0067] Therefore, the drive of the differential 100 in electric traction can be realized in three different ways: either by the main machine 20 , or by the auxiliary machine 40 , or by both electric machines 20 , 40 .

[0068] The possibility of having two motors working in tandem is important because the size of the main motor 20 can be reduced for a target total power.

[0069] By moving the sleeve 53 to the right (ie towards the heat engine), the gearbox input layshaft 45 is coupled to the idler gear 51 which meshes with a fixed pinion 65 carried by the input shaft 60 of the heat engine. Figure 7 The power transmission path shown by the solid line shows that the connection drives the auxiliary motor 40, and the heat engine acts in two directions: the auxiliary motor 40 is either a driving machine and allows the heat engine to start, or a receiving machine, that is, generating electricity and absorbing part of the power of the heat engine in order to charge the battery.

[0070] The pair of gears 51 and pinions 65 and the parking wheel 33 are positioned on the axial edge of the ring gear 102. The pair of gears 51 and pinions 65 do not affect the length of the transmission and contribute to its compactness.

[0071] The input shaft 60 of the transmission corresponds to the shaft of the thermal engine.

[0072] from Figure 2From the left side to the right side, the input shaft 60 carries five fixed pinions, namely, the pinion 61 corresponding to the pinion of the second gear transmission ratio, the pinion 62 corresponding to the pinion of the first gear transmission ratio, the pinion 63 corresponding to the pinion of the third gear transmission ratio, the pinion 64 corresponding to the pinion of the fourth gear transmission ratio and the pinion 65 corresponding to the pinion driving the heat engine through the generator 40.

[0073] The transmission 1 has four independent gear ratios for the thermal engine.

[0074] The fixed pinions 62, 63 (ie odd gear ratios) mesh with idler gears 93, 94 (respectively a first idler gear 93 and a third idler gear 94) carried by a second layshaft 90. This shaft 90 also carries a coupling device comprising a hub 95 and a sliding sleeve 96 or shift sleeve.

[0075] By moving the sleeve 96 to the left (ie, toward the motor 40), the layshaft 90 is coupled to the first idler gear 93. Figure 5 It can be seen from the power transmission path shown by the mid-point chain line that the first gear transmission ratio is established.

[0076] By moving the sleeve 96 to the right (ie towards the heat engine), the layshaft 90 is coupled to the third idler gear 94. Figure 5 As can be seen from the power transmission path shown in solid lines and the shared portion in dashed lines, a third gear ratio is established.

[0077] The two gear ratios are independent and mesh independently of the meshing of the motors 20 , 40 .

[0078] The fixed pinions 61, 64 (ie even gear ratios) mesh with idler gears 83, 84 respectively (respectively second idler gear 83 and fourth idler gear 84) carried by a first layshaft 80. This shaft 80 also carries a coupling device comprising a hub 85 and a sliding sleeve 86 or shift sleeve.

[0079] By moving the sleeve 86 to the left (ie, toward the motor 40), the layshaft 80 is coupled to the second idler gear 83. Figure 6 It can be seen from the power transmission path shown by the mid-point chain line that the second gear ratio is established.

[0080] By moving sleeve 86 to the right (ie towards the heat engine), layshaft 80 is coupled to fourth idler gear 84. Figure 6 The power transmission path shown by the solid line and the shared portion shown by the dotted line establishes a fourth gear ratio.

[0081] The two gear ratios are independent and mesh independently of the meshing of the motors 20 , 40 .

[0082] Thanks to the invention, it is possible to use a generator as a drive machine operating in electric mode.By supporting the traction machine, it reduces the size of the latter.

Claims

1. A transmission (1) for a motor vehicle having hybrid propulsion or traction, the transmission (1) comprising: a first machine (20) comprising a rotor (22) integral with a main power transmission shaft (21), the main power transmission shaft (21) rotating integrally with a main gearbox input shaft (25) via a spline connection (29), the main gearbox input shaft (25) being configured to be coupled or decoupled with the wheels of the vehicle via a first coupling system (31, 32), a second machine (40) comprising a rotor (42) integral with a secondary power transmission shaft (41), the secondary power transmission shaft (41) rotating integrally with a gearbox input layshaft (45) via a spline connection (49), the gearbox input layshaft (45) being configured to be coupled or decoupled with the wheels of the vehicle via a second coupling system (52, 53), and A thermal engine is integral with an input shaft (60), characterized in that the second electric machine (40) is connected to the wheels independently of the thermal engine.

2. The transmission (1) according to claim 1, wherein: The electric motor (20, 40) is integrated into a dedicated compartment of the gearbox at the end of the gearbox.

3. The transmission (1) according to claim 1 or 2, wherein: The electric machine (20, 40) runs in oil, and wherein the transmission (1) comprises a single cooling system for the electric machine (20, 40) and the gearbox.

4. A transmission (1) according to any one of the preceding claims, comprising: A first layshaft (80) and a second layshaft (90), wherein the first layshaft (80) is configured to be coupled to or decoupled from the main gearbox shaft (25), and the second layshaft (90) is configured to be coupled to or decoupled from the gearbox layshaft (45).

5. The transmission (1) according to claim 4, wherein: The main gearbox shaft (25) carries a single idler gear (30), and the first layshaft (80) carries a fixed pinion (82) configured to mesh with the first idler gear (30) and a toothed portion (81) configured to mesh with a ring gear (102) of a differential assembly (100).

6. The transmission (1) according to claim 4 or 5, wherein: The gearbox input layshaft (45) carries two idler gears (50, 51), and the second layshaft (90) carries a fixed pinion (92), which is configured to mesh with a first intermediate pinion (71), the first intermediate pinion (71) is carried by the intermediate shaft (70) and is configured to mesh with the first idler gear (50) of the gearbox input layshaft (45), and the second layshaft (90) also carries a toothing (91) configured to mesh with the ring gear (102) of the differential assembly (100).

7. The transmission (1) according to claim 6, wherein: The heat engine input shaft (60) carries a fixed pinion (65) configured to mesh with a second idler gear (51) of the gearbox input layshaft (45).

8. The transmission (1) according to any one of the preceding claims, wherein: The transmission (1) has a plurality of gear ratios for the heat engine independent of the electric machines (20, 40).

9. The transmission (1) according to claim 8, wherein: The input shaft (60) of the heat engine carries five fixed pinions, namely a pinion (61) corresponding to a pinion of a second gear ratio, a pinion (62) corresponding to a pinion of a first gear ratio, a pinion (63) corresponding to a pinion of a third gear ratio, a pinion (64) corresponding to a pinion of a fourth gear ratio and a pinion (65) corresponding to a drive pinion of the heat engine through the auxiliary motor (40), the fixed pinions (62, 63) of the first gear ratio and the third gear ratio, respectively, being configured to mesh with idler pinions (93, 94) carried by the first secondary shaft (90), and the fixed pinions (61, 64) of the second gear ratio and the fourth gear ratio, respectively, being configured to mesh with idler pinions (83, 84) carried by the second secondary shaft (80), respectively.

10. The transmission (1) according to any one of the preceding claims, further comprising a parking brake device, the parking brake device comprising a toothed wheel (33), the axial position of the toothed wheel (33) being located on an axial edge of the ring gear (102) of the differential assembly (100).

11. The transmission (1) according to claim 10, wherein: The toothed wheel (33) is located on the gearbox input main shaft (25) of the main motor (20) and is integrated into the axial space of the ring gear (102).

12. The transmission (1) according to any one of the preceding claims, wherein: The main motor (20) is offset from the crankshaft axis of the heat engine.

13. A motor vehicle with hybrid propulsion or traction, comprising at least two drive wheels and a transmission (1) according to any one of the preceding claims configured to drive the drive wheels in rotation.

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