WO2014118009A1

WO2014118009A1 - Drive train

Info

Publication number: WO2014118009A1
Application number: PCT/EP2014/050789
Authority: WO
Inventors: Rudolf Glassner
Original assignee: Magna Powertrain Ag & Co Kg
Priority date: 2013-02-01
Filing date: 2014-01-16
Publication date: 2014-08-07
Also published as: DE102013201711A1; DE102013201711B4

Abstract

The invention relates to a drive train of a motor vehicle, comprising at least one combustion engine, an electric machine (18), and a transmission unit (10, 10'), wherein the transmission unit (10, 10') comprises a first input shaft (14), which is drivingly coupled to the combustion engine, a second input shaft (16), which is drivingly coupled to the electric machine (18), and an output shaft (22), which is arranged coaxially to the second input shaft (16), and wherein the first input shaft (14) and the second input shaft (16) are drivingly coupled to the output shaft (22) via a summation gearbox (20).

Description

powertrain

The present invention relates to a drive train of a motor vehicle, which has at least one internal combustion engine, an electric machine and a transmission unit.

Vehicles that can be driven both by an electric motor and by an internal combustion engine are called hybrid vehicles. Such vehicles require special drive trains. Depending on the design, in addition to a pure electric drive of the vehicle, they also enable an electric drive supported by the internal combustion engine. That is, a drive torque of the electric machine is increased as needed by a drive torque of the internal combustion engine. Hybrid drive concepts can - with efficient construction - lead to a considerable fuel saving, which can be a buying argument in times of rising fuel prices and stricter emission standards. The integration of an electric machine in a drive train of a hybrid vehicle is conventionally carried out by transmission with a plurality of spur gears. Corresponding concepts are described, for example, in the publications DE 199 60 621 B4, DE 10 2010 063 092 A1, DE 10 201 1077 594 A1, DE 10201 1 002 472 A1 and DE 10 2012 103 367 A1. The known concepts are relatively complex and comprise a plurality of components, which has a negative effect on the efficiency of the drive train and / or on its manufacturing costs. In addition, they require a comparatively large amount of space. WO 2012/087700 A1 discloses a module with an electric motor for driving an axle of a vehicle. A combination of the drive torques of an internal combustion engine of the vehicle and the electric motor for the common drive of a common output shaft is not provided.

It is an object of the present invention to provide a powertrain that enables efficient convergence of drive torques of an internal combustion engine and an electric machine of a hybrid vehicle. The corresponding concept should also be cost-effective and require little building space.

The solution of the above object is achieved by a drive train having the features of claim 1. The drive train according to the invention comprises a transmission unit with a first input shaft which is drive-actively coupled to the internal combustion engine and with a second input shaft drivingly coupled to the electric motor. In addition, a coaxially arranged to the second input shaft output shaft is provided. The first input shaft and the second input shaft are drivingly coupled to the output shaft via a summing gear.

In other words, the summation gear unites the drive torques of the internal combustion engine and the electric machine and efficiently routes them to a common output shaft. The compact design of the gear unit - and thus of the drive train - is made possible by the coaxial arrangement of the output shaft and the second input shaft.

Further embodiments of the present invention are set forth in the description, claims and appended drawings. According to one embodiment of the drive train, the first input shaft is coupled via a shiftable transmission with at least one gear stage selectively selectable by means of a coupling mechanism with the summing gear in order to be able to supply the drive torque of the internal combustion engine as needed. The selectively selectable gear stage includes in particular a spur gear.

A compact design results when the summation gear is arranged coaxially with the second input shaft and the output shaft, in particular when it is arranged in the axial direction between the second input shaft and the output shaft. This arrangement also facilitates, inter alia, the storage of said components.

According to a further embodiment of the drive train, the summation transmission is a planetary gear. The planetary gear may comprise a first sun gear associated with the first input shaft, a second sun gear associated with the second input shaft, at least one first and at least one second planet gear, and a planet carrier associated with the output shaft. The first planetary gear meshes with the first sun gear and the second planetary gear meshes with the second sun gear. In addition, the two planetary gears are drivingly coupled together in this embodiment.

The drive-effective coupling of the first and the second planetary gear can be made by meshing with each other. Alternatively, it can also be provided to couple the first and the second planetary gear rotatably with each other. For example, a stepped planet may be used, which has two differently shaped toothed sections, which mesh with one of the sun gears. The first sun gear may for example be connected directly to the first input shaft. But it is also possible to couple the second sun gear via other components with the first input shaft to make an indirect connection. The same applies to the second input shaft and the second sun gear.

An indirect drive-effective coupling between the first input shaft and the summation can be easily produced by an intermediate shaft. In order to make the gear unit as compact as possible, the intermediate shaft may be arranged coaxially to the output shaft and this particular surrounding at least in sections. The intermediate shaft is formed for example as a hollow shaft.

The first input shaft and the intermediate shaft can be offset in parallel.

Furthermore, it can be provided that the first input shaft and the intermediate shaft can be selectively coupled to one another. For example, the first input shaft and the intermediate shaft are coupled with each other via at least one spur-gear stage in an effective manner with each other or can be coupled to one another in order to be able to feed the drive torque of the internal combustion engine into the summation gear as required.

In particular, the spur gear stage comprises at least one toothed wheel designed as a loose wheel which can be coupled in a rotationally fixed manner to the first input shaft or to the intermediate shaft by means of a coupling mechanism. The spur gear forms, for example, a gear stage of a switchable transmission. It is understood that the shiftable transmission may include any number of gear ratios to meet the requirements in each case can. Preferably, two gears are provided. Another measure for the realization of a space-optimized design may be to arrange the second input shaft and the output shaft in the axial direction one behind the other.

The output shaft can be drive-coupled with a differential gear, in particular with a differential carrier of the differential gear of a driven axle of the motor vehicle. According to an advantageous embodiment, the coupling mechanism comprises at least one jaw clutch or at least one friction clutch. Jaw clutches are robust, reliable and cost effective. Another advantage is their usually compact design. By contrast, friction clutches enable power-shift operation of the shiftable transmission. This is particularly important when a shiftable transmission is provided with two or more gear ratios, by which the drive torque of the engine can be under or translated before it is fed to the summation. Hereinafter, the present invention will be explained purely by way of example with reference to advantageous embodiments with reference to the accompanying figures. Show it:

1 shows a first embodiment of the transmission unit of the drive train according to the invention,

2 is a circuit diagram of the shiftable transmission of the transmission unit,

Fig. 3 is a schematic representation of the spur gears of the gear unit of FIG. 1 in an axial view and Fig. 4 shows a second embodiment of the transmission unit of the drive train according to the invention. 1 shows a transmission unit 10 of a drive train of a hybrid vehicle. The powertrain includes an internal combustion engine, not shown, whose output shaft is coupled to a torsional vibration damper 12. Between the gear unit 10, the internal combustion engine and after the torsional vibration damper 12, a coupling device may be provided in order to decouple the internal combustion engine if necessary from the drive train can.

The torsional vibration damper 12 is rotatably coupled to a first input shaft 14 of the transmission unit 10. The gear unit 10 further includes a second input shaft 16 which is rotatably connected to a rotor 18a of an electric machine 18. In other words, the transmission unit 10 may be supplied torque through both the first and second input shafts 14 and 16, respectively. These input torques are combined by a summing gear 20 designed as a planetary gear and fed to an output shaft 22. From the output shaft 22, the combined drive torque of the internal combustion engine and the electric machine 18 is transmitted via a spur gear 24 with gears 24a, 24b to a differential carrier 26a of a differential gear 26 of a driven axle A of the vehicle.

In order to be able to provide the drive torque generated by the internal combustion engine to the summation gear 20 in a demand-oriented manner, a shiftable transmission 28 is provided which comprises two spur gear stages 30a, 30b. The spur gears 30a, 30b each include a fixedly connected to the first input shaft 14 gear 32a and 32b. The gears 32a, 32b mesh with a gear 34a and 34b, respectively. The toothed wheels 34a, 34b are each selectively and independently of one another by a dog clutch C2 or C1. nander with a clutch hub 38 rotatably coupled. In principle, it is also conceivable to provide a selective coupling of the toothed wheels 32a, 32b with the input shaft 14 and to connect the toothed wheels 34a, 34b firmly to the intermediate shaft 40.

The clutch hub 38 is connected to a formed as a hollow shaft intermediate shaft 40, which in turn is drivingly coupled to the summation gear 20. The intermediate shaft 40 surrounds the output shaft 22 and is therefore also arranged coaxially with the second input shaft 16.

The summing gear 20 includes on the input side, on the one hand a rotatably coupled to the intermediate shaft 40 first sun gear 42 and on the other hand rotatably coupled to the second input shaft 16 second sun gear 44. The summing gear 20 further includes planetary gears 46, 48, both with one of the sun gears 42, 44th as well as comb with each other, which is indicated by the line K. The planet gears 46, 48 are mounted on a planetary carrier 50.

The torques introduced by the sun gears 42, 44 into the summing gear 20 are superimposed by the intermeshing planet gears 46, 48 and converted into a rotational movement of the planet carrier 50, which in turn is non-rotatably coupled to the output shaft 22. As already described above, the torque of the output shaft 16 is then transmitted via the spur gear 24 to the driven axle A of the vehicle.

On the one hand, the transmission unit 10 enables an efficient combination of the drive torques of the internal combustion engine and of the electric machine 18, since comparatively few components are involved in the torque transmission. Due to the design of the summing gear 20 as a planetary gear, the transmission unit 10 also requires little space. The needs-based The torque generated by the internal combustion engine is supplied via the compact and robust switchable transmission 28, which comprises two gear stages. It is understood that only one gear or more than two gear ratios can be provided.

Fig. 2 shows a tabular circuit diagram, which results from the various possible switching states of the dog clutches C1, C2. When both clutch C1 and clutch C2 are engaged - i.e. the gear wheels 34a, 34b are both coupled in a rotationally fixed manner to the intermediate shaft 40 via the clutch hub 38, so the shiftable gear 28 is blocked. This condition assumes that the engine is not in operation or decoupled from the input shaft 14 by a suitable clutch. Due to the blockage of the shiftable transmission 28, the first sun gear 42 is also locked in a fixed angular position, so that only the drive torque generated by the electric machine 18 is transmitted to the output shaft 22. This state defines not only a first gear but also a reverse gear, since the direction of rotation of the output shaft 22 - and thus the axis A - by the direction of rotation of the rotor 18a of the electric machine 18 can be determined. To form a second gear stage of the transmission unit 10, only the

Clutch C1 engaged. The clutch C2 is not engaged in this situation, so that the mounted on a portion of the intermediate shaft 40 gear 34a freely rotates upon rotation of the input shaft 14. The under or translation of the drive torque of the internal combustion engine is thus determined by the configuration of the gears 32b, 34b.

A third speed step of the transmission unit 10 is effected by engagement of the clutch C2 while the clutch C1 is disengaged, so that the gear 34b mounted on a portion of the output shaft 22 is free to rotate. If one uses friction clutches instead of the illustrated dog clutch C1, C2, we obtain a power shift transmission. By an overlapping control when opening or closing the clutches namely a torque drop during a gear stage change can be avoided.

The compact design of the gear unit 10 results on the one hand by the coaxial arrangement of the second input shaft 16 and the output shaft 22, which are coupled to each other by the intermediate and both in the radial direction and in the axial direction compact summation 20. The feeding of the torque of the internal combustion engine also takes place in the coaxial direction via the intermediate shaft 40 designed as a hollow shaft, which in turn is in drive-driving connection via the compact and robust helical gear 28 with the first input shaft 14 and thus ultimately with the internal combustion engine.

Instead of the relatively simple summing gear 20 of the transmission unit 10, a Ravigneaux set can also be used.

3 shows a so-called. Wheel scheme - ie an axial view of the gear unit 10, wherein the summation gear 20 described in detail to avoid overloading of Fig. 3 was not shown - to the compact design of the gear unit 10 in the radial direction clarify. It can be seen that the shafts 14, 16, 22 and A have only a comparatively small parallel offset. The spur gear 30a, 30b with the gears 32a, 34a and 32b, 34b have a relatively small space requirement in the radial direction. In other words, the radial extent of the gear unit 10 is significantly smaller than the corresponding space requirement of the torsional vibration damper 12, the electric machine 18 and the spur gear 24th 4 shows an embodiment 10 'of the gear unit, which is particularly suitable for longitudinally installed drives or for installation in a transaxle. The driven axis A is here perpendicular to the input shafts 14, 16, the intermediate shaft 40 and the output shaft 22 is arranged. The transfer of the drive torque from the output shaft 22 to the differential gear 26 via bevel gear teeth 24a ', 24b'.

In Fig. 4, no torsional vibration damper is shown. However, this may be provided if necessary or desirable. The same applies to a clutch for decoupling the internal combustion engine from the input shaft 14.

Instead of the summation 20 of the gear units 10, 10 'with intermeshing planetary gears 46, 48, a planetary gear with stepped planetary can be used. In this case, at least one step planet is provided, which has two coaxially arranged toothed sections which, for example, have different pitch circle radii and which mesh with one of the sun gears 42 and 44, respectively.

Reference character list, 10 'gear unit

Torsional vibration damper first input shaft second input shaft rotor

electric machine

summing

output shaft

, 30a, 30b spur gear stage

a, 24b, 24a ', 24b' toothing

a, 32b, 34a, 34b gear

Differential gear Differential carrier

switchable gearbox clutch hub

intermediate shaft

first sun gear second sun gear

, 48 planetary gear

Planet carrier driven axle Claw clutch

drive-effective coupling

Claims

claims

Drive train of a motor vehicle, the at least one internal combustion engine, an electric machine (18) and a transmission unit (10, 10 '), wherein the transmission unit (10, 10') to the internal combustion engine drive-coupled first input shaft (14), one with the electric machine (18) drivingly coupled second input shaft (16) and coaxial with the second input shaft (16) arranged output shaft (22) and wherein the first input shaft (14) and the second input shaft (16) via a summation gear (20) drivingly with the Output shaft (22) are coupled.

Drive train according to claim 1,

in which the first input shaft (14) is coupled to the summing gear (20) via a shiftable transmission (28) with at least one gear stage (32a, 34a or 32b, 34b) which can be selectively selected by means of a coupling mechanism (C2, C1).

Drive train according to claim 2,

wherein the selectively selectable gear stage comprises a spur gear (32a, 34a and 32b, 34b).

Drive train according to at least one of the preceding claims, wherein the summation gear (20) is arranged coaxially to the second input shaft (16) and the output shaft (22), in particular in the axial direction between the second input shaft (16) and the output shaft (22). Drive train according to at least one of the preceding claims, wherein the summation gear (20) is a planetary gear.

Drive train according to claim 5,

wherein the planetary gear one of the first input shaft (14) associated with the first sun gear (42), a second input shaft (16) associated with the second sun gear (44), at least a first and at least one second planetary gear (46 and 48), which drive together coupled, and a planet carrier (50) which is associated with the output shaft (22).

Drive train according to claim 6,

wherein the first and the second planet gear (46 and 48) mesh with each other or that the first and the second planetary gear are rotatably coupled to each other.

Drive train according to at least one of the preceding claims, wherein the first input shaft (14) and the summation gear (20) via an intermediate shaft (40) are drivingly coupled together, which is in particular designed as a hollow shaft.

Drive train according to claim 8,

in which the first input shaft (14) and the intermediate shaft (22) are arranged offset in parallel. Drive train according to claim 8 or 9,

in which the intermediate shaft (40) is arranged coaxially with the output shaft (22) and surrounds it in particular at least in sections.

Drive train according to at least one of claims 8 to 10,

in which the first input shaft (14) and the intermediate shaft (40) can be selectively coupled to one another.

Drive train according to at least one of claims 8 to 1 1,

in which the first input shaft (14) and the intermediate shaft (40) can be coupled or coupled to one another in terms of drive via at least one spur gear stage (32a, 34a or 32b, 34b).

Drive train according to claim 12,

in which the spur gear stage (32a, 34a or 32b, 34b) comprises at least one toothed wheel (34a, 34b) designed as idler gear which is selectively rotationally fixed to the first input shaft or to the intermediate shaft (40) by means of a coupling mechanism (C2 or C1). can be coupled.

14. Drive train according to at least one of the preceding claims,

in which the second input shaft (16) and the output shaft (22) are arranged one behind the other in the axial direction. Drive train according to at least one of the preceding claims, in which the output shaft (22) is drivingly coupled to a differential gear (26), in particular to a differential cage (26a) of the differential gear (26) of a driven axle of the motor vehicle.

16 drive train according to at least one of the preceding claims,

in which the coupling mechanism has at least one jaw clutch (C1,

C2) or at least comprises a friction clutch.

17. Drive train according to at least one of the preceding claims,

wherein the coupling mechanism (C1, C2) is coaxial with the output shaft (22).