DE102011014098A1 - Drive assembly for a motor vehicle - Google Patents

Abstract

The invention relates to a drive assembly for a motor vehicle, which is arranged between an engine and an output shaft, with a CVT transmission, which has a variator and a flywheel accumulator with a flywheel and gears, a switching group being arranged between the output of the variator and the output shaft is, which ensures switching between a forward gear and a reverse gear and realizes a division of the forward gear into at least a first driving range and a second driving range.

Description

The invention relates to a drive assembly for a motor vehicle with a CVT transmission, a flywheel accumulator and an adjustable transmission (variator).

Such transmission structures with flywheel storage are already known and are for example in the publications WO 2007/138353 A2 . WO 82/00270 A1 and DE 25 15 048 B2 described.

According to WO 2007/138353 is a hybrid drive with a flywheel storage known, which is connected via an arrangement of a plurality of switchable clutches with a transmission input shaft of a continuously variable transmission.

The WO 82/00270 A1 includes a continuously variable transmission and four clutches. A clutch connects a prime mover to a flywheel and another clutch connects the flywheel to an intermediate gear member. Another clutch connects the prime mover with an output shaft and another clutch the intermediate gear member to the output shaft. The transmission is associated with a differential gear having three gear members and is preferably formed as a planetary gear. The continuously variable transmission is composed of two individual hydrostatic units. From the planetary gear set the ring gear is connected to the prime mover, the sun gear with the one hydrostatic unit and the planet carrier with the intermediate gear member and simultaneously with another hydrostatic unit. With this solution, a simple as possible continuously variable transmission should be created, in which the course of the power distribution should be changeable. However, the use of four couplings requires a high level of design and production engineering effort.

In the DE 25 15 048 the flywheel storage is hydraulically coupled to an internal combustion engine, wherein the flywheel storage can deliver a torque to the wheels driven by an internal combustion engine.

Although such transmission structures can always set the appropriate gear ratios to optimally use the flywheel and to keep the efficiency from recovery to reuse at the best level. The translation can change continuously and without a jump (neither in the overall ratio nor in the variator ratio). But at the same time it also means more effort in terms of the transmission structure and also a higher complexity for the controller. This in turn leads to a transmission which has a relatively high weight and can be produced with a high production and control engineering effort.

There are also from unpublished fonts power-split geared neutral CVT transmission with integrated flywheel memory known, in which a decoupled flywheel is integrated, which stores kinetic energy during deceleration phases of the motor vehicle and at the next acceleration the drivetrain available again and by the Geared Neutral point reduces start-up losses. The flywheel is used for recuperation. This transmission has a relatively complicated structure.

The object of the invention is to develop a drive assembly for a motor vehicle with a CVT transmission, a flywheel storage and an adjustable transmission (variator), which has a weight-saving, simple and compact structural design.

This object is achieved with the characterizing features of the first claim. Advantageous embodiments emerge from the subclaims.

The drive assembly for a motor vehicle, which is arranged between a motor and an output shaft, has a CVT transmission with a variator and a flywheel accumulator with a flywheel and gears, wherein arranged between the output of the variator and the output shaft of the CVT transmission, a switching group is, which ensures switching between a forward gear and a reverse gear and realizes a division of the forward gear in at least a first driving range and a second driving range.

This achieves a simple and compact design of the drive assembly.

For this purpose, the switching group has at least a first switching element, which ensures the switching between the forward gear and the reverse gear and at least a second switching element, which realizes the division of the forward gear in at least a first driving range and a second driving range.

For the design of the switching group several variants are possible.

In a first variant, the switching group can be a switching element for switching between the forward gear and the reverse gear in the form of a first dog clutch and a second switching element for dividing the forward gear in at least a first driving range and a second driving range in the form of a second dog clutch, wherein for the reverse gear, a first gear stage, for the first driving range of the forward gear, a second gear stage and for the second driving range of the forward gear, a third gear stage in the switching group is integrated.

In a second variant, the switching group for realizing the two forward ratios of the first and second driving range of the forward gear and the reverse ratio of the reverse gear, a planetary gear set with two clutches in combination with a dog clutch, wherein the dog clutch between the first and the second driving range of the forward gear and the Reverse is switchable.

According to a third variant, the switching group for realizing the two forward ratios of the first and second driving range of the forward gear and the reverse ratio of the reverse gear may comprise a Ravigneaux set with two clutches in combination with a dog clutch.

Advantageously, the CVT transmission when switching between the first and second driving range is reset again, the overall ratio of the transmission is approximately twice the ratio of the CVT.

Transmission input side, an engine disconnect clutch is arranged to the engine. This is followed by a flywheel storage, the flywheel is connected via a flywheel clutch, wherein the flywheel with the input shaft of the CVT transmission by means of a double planetary gear set (about 10) by closing the flywheel clutch is connectable. As a result, the flywheel storage in the overrun mode of the vehicle is infinitely accelerated and thus rechargeable and it is the other way around a drive only via the flywheel of the flywheel storage possible.

The drive assembly according to the invention ensures both a large starting ratio and a long overdrive ratio. Thanks to these two special features, the starting losses can be significantly reduced compared to a conventional gearbox. Furthermore, the engine speed can be reduced thanks to the long overdrive ratio at higher speeds, which reduces fuel consumption and thus emissions.

The flywheel also allows the storage of energy in the form of kinetic energy during the deceleration phases of the vehicle and supports or replaces the brake. This energy is returned to the powertrain at the next approach or acceleration.

The storage of the braking energy in the flywheel storage and thereby to increase the speed of this flywheel by a variable ratio change, has significant advantages over systems with multiple fixed ratios (multi-speed transmission such as stepped, double clutch or automatic transmission), as by the stepless braking energy mostly goes into the flywheel instead of getting lost in the gear change.

However, this also requires a large spread in order to be able to adapt the speed of the flywheel to that of the drive train in every driving situation, with the marginal ratios Underdrive (i UD) and Overdrive (i OD) being of importance. The optimal UD ratio is defined as the ratio between the maximum allowable speed of the flywheel and the minimum speed of the drivetrain.

Likewise, the OD ratio is set as the ratio between the minimum speed of the flywheel and the maximum speed of the driveline. In reality, attempts are made to approach these values, limited by the technical boundary conditions in the form of variator spread, number of areas, translations of the solid levels, etc. The peculiarity of the flywheel system of the solution according to the invention is the limited range of translation, where the Flywheel storage is loaded or unloaded. Depending on the vehicle class (vehicle weight, driving resistance, rolling radius), flywheel characteristic (inertia mass, maximum permitted speed) and driving cycle, there is a limit conversion for the recovery (i_rgw) and a limit translation for the return (i_rga). Therefore, the peculiarity of this invention also lies in the fact that the transmission is a multi-range CVT whose translation ranges correspond to these limit ratios.

For example, if the areas [i_UD; i_rga] and [i_rgw; i_OD] can overlap, a 2 range gear can be used, in which these translations represent the edge translations of the first and second area. If there is no overlap, it is conceivable to expand the areas to overlap and thus always use a 2-area.

Alternatively, it is also possible to realize a 3-range system in which the forward gear has three driving ranges. With this solution but would be expected again with more weight and cost.

In order to achieve the best possible coupling between the flywheel and the drive train, the corresponding speed difference must be the lowest (ideally these two speeds should be identical, ie connected to a ratio = 1). For the best vehicle braking and energy recovery must be increased by a variable ratio change the flywheel speed, so it is a large translation in the fast necessary. Due to the fast adjustment and the large spreading requirement, the loads on the variator are increased. Another important point for increasing efficiency is to restore energy stored in flywheel storage to the powertrain. For the course with the lowest losses must be carried out, similar to the recuperation: Start, translation, infinite from the flywheel to the powertrain (Geared Neutral), the end of translation 1. But the difficulty is to realize with little effort fixed switchable translations which, in combination with a variator, can realize the required range ratios. This is possible with the solution according to the invention for example by fixed gear ratios and claw circuits or by a planetary gear or a Ravigneaux planetary gear set, both in combination with wet clutches or brakes.

Alternatively, it may also be possible not to use the solution according to the invention as the main transmission (ie not between the engine and the wheel), but as an additional solution in the form of an add-on module which is coupled directly to the wheel. This option simplifies the control effort between the engine and the wheel, but does not replace the existing transmission of the drivetrain. This variant would have the advantage of being accommodated in existing drive trains, especially if no CVT transmission is to be used as the main transmission.

The invention will be explained in more detail with reference to an embodiment and associated drawings. Show it:

1 a drive assembly with an indicated switching group between variator and output shaft,

2 a drive assembly in which jaw clutches are used in the switching group for switching between D and R and for switching between the driving ranges,

3 Representation of a switching group with a planetary gearset,

4 Representation of a switching group with a Ravigneaux sentence,

5 Drive assembly with an electric motor.

The drive assembly points according to 1 and 2 following structure:
Transmission input side is to the engine 1 (Internal combustion engine) an engine disconnect clutch KM arranged. After the engine disconnect coupling KM, the flywheel is a flywheel via a flywheel clutch KSR 3 switchable, the speed of a connected with this double planetary stage 2 can be increased many times over. The flywheel clutch KSR is followed by a variator 4 on, over which the whole input power runs. Between the output shaft 5 of the variator 4 and the output shaft 6 of the CVT transmission is arranged a switching group S, which allows a circuit between different forward speeds and a circuit between forward and reverse.

At the output of the switching group S, the power is applied to the output shaft 6 and thus the axis 7 and the wheels 8th transfer.

The double planetary stage 2 increases the speed from the transmission input to the flywheel 3 around a factor 10 , This not only allows the speed of the flywheel 3 during the deceleration phases most often, but synchronizes the flywheel speed with the engine 1 , However, the flywheel is spinning 3 for example, between 10,000 rpm and 30,000 rpm, because the design parameters have led to these values (cycle, flywheel mass inertia, energy that has to be stored kinetically), that means with one factor 10 (slow this time, because in the direction of the drivetrain) a transmission input speed between 1,000 rpm and 3,000 rpm.

The big advantage, for example, when driving through the flywheel 3 , When all the energy is consumed, the input speed will be around 1,000 rpm and can thus be at the combustion engine 1 be coupled without losses or shocks. If the approach must be made from the combination of flywheel and engine power, it is also possible to use the engine 1 with the work area of the flywheel 3 1,000 rpm-3,000 rpm.

1 shows a schematic representation of the switching group S within the drive assembly and 2 a constructive variant of the switching group S within the drive assembly.

In this embodiment, in the switching group S, a first dog clutch 9.1 for selecting the forward direction D or the reverse direction R and a second dog clutch 9.2 to the choice of first driving range F1 and the second driving range F2 provided. The reverse gear R is a first gear ratio U1 with gears Z1 and Z2 the, the first driving range F1 a second gear stage U2 with gears Z3, Z4 and the second driving range F2 associated with a third gear stage with gears Z5, Z6.

Will the first dog clutch 9.1 in the direction R (reverse) engaged with the gear Z1, the first gear Z1 is connected to the output shaft 6 connected and the second gear Z2 with the output shaft 5 of the variator 4 ,

Will the first dog clutch 9.1 switched to D (forward), this is with the shaft 10 coupled, on which sit the gears Z5 and Z3. Will the second dog clutch 9.2 in the direction F1 (first driving range) is engaged with the fourth gear Z4 is via the variator 4 , whose output shaft 5 , the second gear stage U2 (gears Z4, Z3) the power to the shaft 10 and above through the first dog clutch 9.1 on the output shaft 6 transfer.

If a switching operation of the second dog clutch 9.2 in the direction F2 (second driving range), this is brought into engagement with the sixth gear Z6 and takes place via the variator 4 , whose output shaft 5 the third gear stage U3 (gears Z6, Z5) transmits power to the shaft 10 and above through the first dog clutch 9.1 on the output shaft. The two driving ranges each realize different speed ranges. The first driving range F1 has a lower speed range than the second driving range F2.

In the two driving ranges F1 and F2, the entire transmission range of the variator 4 used.

Between two driving ranges F1 and F2 is a return adjustment of the variator 4 necessary to get to the synchronous speed of the other area. As an example, the variator 4 approached in Underdrive and in the first driving range F1 the variator 4 adjusted to overdrive. Thereafter, a traction interruption takes place while the variator 4 From Overdrive to Underdrive adjusted, simultaneously opens the second claw clutch 9.2 and thus releases itself from the first driving range (from toothed wheel Z4) and changes into the second driving range (engagement with toothed wheel Z6). The second dog clutch 9.2 thus concludes from the moment where the variator 4 has achieved the underdrive translation. After that, the variator adjusts 4 back to overdrive to find the final ratio of the entire CVT transmission.

For reverse, it is possible to have a first dog clutch 9.1 which decides between forward D and reverse R This is according to 2 after the two fixed translations U2, U3 towards differential 11 accommodated.

Thus, it would also be possible to realize two speed ranges when reversing. Another constructive solution would be a fixed stage to the variator 4 to bridge.

In order to realize two forward translations (one to the slow F1 and one to the fast F2) and one reverse to the slower, other constructive solutions of the group S are also possible.

The representation of a switching group S with a planetary gearset 20 is in 3 shown. The planetary gearset has for this purpose two clutches K1 and KR. With K1 the first driving range F1 and with KR the reverse speed is switchable. By a third claw clutch 9.3 becomes towards the output shaft 6 between the first and second driving range (F1, F1) when driving forward D and between reverse driving R switched.

According to 4 can for the realization of the two speed levels F1, F2 also a shift group S with a Ravigneaux set 30 be used. A clutch K1R is switchable for the first driving range F1 and the reverse gear R, and a clutch K2 for the second driving range F2. A fourth claw clutch 9.4 switches between forward and reverse D, R.

5 shows a drive assembly with a multi-range CVT with integrated electric motor (electric motor). The switching group S corresponds to the switching group S according to 3 , The optimal adjustment of the input speed of the transmission allows to use the electric motor always in its optimum speed range. Due to the flexibility of its speed this can also be varied and adapted to ensure in some special cases with the best comfort, the transfer from the engine to the electric motor.

The rotor of the electric motor can also be decoupled by a clutch KM from the rest of the driveline, so as not always mitzuschleppen its mass.

The energy of the flywheel accumulator SP, which is a flywheel 3 can, via a generator 40 also a battery 50 be fed and stored in this.

Alternatively, it is possible, according to an embodiment not shown the Flywheel storage directly by an electric motor to replace.

The variator preferably comprises a chain-wound belt drive, but may also be designed as another system, for example as a hydrostat. As a main transmission, however, such a solution would be inferior in terms of efficiency.

Due to the novel drive assembly, it is possible to reduce the consumption of the motor vehicle (car or truck) to a considerable extent, creating new standards in terms of energy efficiency.

LIST OF REFERENCE NUMBERS

1

engine

2

Double planetary gear set

3

flywheel

4

variator

5

output shaft

6

output shaft

7

axis

8th

bikes

9.1

first dog clutch

9.2

second dog clutch

9.3

third claw clutch

9.4

fourth claw clutch

10

wave

11

differential

20

planetary set

30

Ravigneaux set

40

generator

50

battery

F1

driving range

F2

driving range

KM

Engine separating clutch

D

forward direction

E-Motor

electric motor

KSR

Flywheel clutch

K1, KR

Couplings of the planetary gear set 20

K2, K1R

Clutches of the Ravigneaux set 30

R

reverse direction

S

switching group

SP

flywheel energy storage

U1

first translation stage

U2

second translation stage

U3

third translation level

Z1

first gear

Z2

second gear

Z3

third gear

Z4

fourth gear

Z5

fifth gear

Z6

sixth gear

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2007/138353 A2 [0002]
• WO 82/00270 A1 [0002, 0004]
• DE 2515048 B2 [0002]
• WO 2007/138353 [0003]
• DE 2515048 [0005]

Claims (10)

Drive assembly for a motor vehicle which is connected between a motor ( 1 ) and an output shaft ( 6 ) is arranged with a CVT transmission, which has a variator ( 4 ) and a flywheel storage with a flywheel ( 3 ) and gears, wherein between the output ( 5 ) of the variator ( 4 ) and the output shaft ( 6 ), a switching group (S) is arranged, which ensures switching between a forward gear (D) and a reverse gear (R) and a division of the forward gear (D) realized in at least a first driving range (F1) and a second driving range (F2). Drive assembly according to claim 1, characterized in that the switching group (S) has at least one first switching element, which ensures the switching between the forward gear (D) and the reverse gear (R) and that the switching group (S) has at least one second switching element, which the division of the forward gear (D) in at least a first driving range (F1) and a second driving range (F2) realized. Drive assembly according to claim 1 or 2, characterized in that the first switching element for switching between the forward gear (D) and the reverse gear (R) a first dog clutch and that the second switching element for dividing the forward gear (D) in at least a first driving range (F1 ) and a second driving range (F2) is a second jaw clutch, wherein for the reverse gear, a first gear stage, for the first driving range of the forward gear, a second gear stage and for the second driving range of the forward gear, a third gear stage in the switching group (S) is provided. Drive assembly according to claim 1 or 2, characterized in that the switching group (S) for realizing the two forward ratios of the first and second driving range of the forward gear (D) and the reverse gear ratio of the reverse gear (R) a planetary gear set ( 20 ) with two clutches (K1, KR) in combination with a third jaw clutch ( 9.3 ) having. Drive assembly according to claim 4, characterized in that the third dog clutch ( 9.3 ) between the first and the second driving range (F1, F2) of the forward gear (D) and the reverse gear (R) is switchable. Drive assembly according to claim 1 or 2, characterized in that the switching group (S) for realizing the first and second driving range (F1, F2) during forward travel (D) and the reverse gear ratio when reversing (R) a Ravigneaux sentence ( 30 ) with two clutches (K1R, K2) in combination with a fourth claw clutch ( 9.4 ) having. Drive assembly according to one of claims to 6, characterized in that the CVT transmission when switching between the first and second driving range (F1, F2) is wiederzustellbar again. Drive assembly according to one of claims 1 to 7, characterized in that the total ratio of the transmission is twice the ratio of the CVT. Drive assembly according to one of claims 1 to 8, characterized in that the transmission input side to the motor ( 1 ) an engine disconnect clutch (KM) is arranged and that behind it via a flywheel clutch (KSR) the flywheel ( 3 ) of the flywheel accumulator (SP) is switchable, wherein the flywheel ( 3 ) with the input shaft of the CVT transmission by means of a double planetary gear set ( 2 ) (Translation about 10) by closing the flywheel clutch (KSR) is connectable. Drive assembly according to one of claims 1 to 9, characterized in that the flywheel accumulator (SP) in the overrun mode of the vehicle is continuously accelerated and thus rechargeable and that, conversely, a journey only via the flywheel ( 3 ) of the flywheel accumulator (SP) is possible.

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