DE102019129635A1 - Drive device for a motor vehicle - Google Patents

Abstract

The invention relates to a drive device (1) for a motor vehicle, comprising an electric drive machine which is operatively connected to a transmission device (3) via a drive shaft (2), the transmission device (3) having at least one first and second planetary gear set (4, 5). as well as a differential stage (6), the first and the second planetary gear stage (4, 5) being operatively connected to a double clutch device (11) with a first and a second power shift clutch (12a, 12b), and wherein a sun gear (9a, 9b ) a planetary gear set (4, 5) and a ring gear (10a, 10b) of the other planetary gear set (4, 5) are non-rotatably connected to one another.

Description

The invention relates to a drive device for a motor vehicle, comprising an electric drive machine which is operatively connected to a transmission device via a drive shaft, the transmission device having at least a first and second planetary gear stage and a differential stage, and the first and second planetary gear stage having a double clutch device a first and a second power shiftable clutch are operatively connected.

Drive devices for motor vehicles are already known from the prior art. For example shows DE 10 2011 088 668 A1 a drive device with at least one electric drive machine, with at least one first planetary drive with a clutch and with a differential. A rotor shaft of the drive machine is coupled non-rotatably to a first connection shaft of the planetary drive formed from at least three connection shafts. A second connecting shaft of the first planetary drive can be fixed in a rotationally fixed manner against a component of the drive device by means of a shift sleeve of the clutch. A third connection shaft of the first planetary drive is operatively connected to a sum shaft of the differential. The shift sleeve can be shifted in positive engagement either with the second connection shaft of the first planetary drive or in a torque-transmitting operative connection with the sum shaft of the differential.

Also shows the DE 10 2004 024 086 A1 a drive device for motor vehicles with a drive unit that acts on two output shafts via a differential gear, with a device being provided on the output shafts with the interposition of at least one superposition gear, by means of which the output torque can be shifted from one output shaft to the other output shaft. To provide a drive device that is particularly effective in terms of control technology and function, it is proposed that the device be formed by at least one electric machine that can be switched as an electric motor and as a generator.

However, the prior art always has the disadvantage that a large number of different parts and components are installed due to a complex transmission structure and therefore the production costs increase and assembly is made more difficult.

It is therefore the object of the invention to avoid or at least mitigate the disadvantages of the prior art. In particular, a drive device or a drive train for a motor vehicle is to be further developed, the focus being on the simplest possible transmission structure with many identical parts and a suitable gear ratio distribution or spread.

This object is achieved according to the invention in a device of the generic type in that a sun gear of one planetary gear set and a ring gear of the other planetary gear set are (permanently) connected to one another in a rotationally fixed manner.

The drive device according to the invention for a motor vehicle comprises an electric drive machine which is operatively connected to a transmission device via a drive shaft.

This has the advantage that two-speed operation can be implemented in the drive train with the simplest possible transmission structure.

The transmission device has at least a first and second planetary gear set and a differential stage, the first planetary gear set having a first planetary gear set with several planet gears, the planet gears of the first planetary gear set being rotatably arranged on a first planetary gear carrier and with a first sun gear and a first ring gear The second planetary gear set has a second planetary gear set with a plurality of planetary gears, the planetary gears of the second planetary gear set are rotatably arranged on a second planetary gear carrier and mesh with a second sun gear and a second ring gear, and the first and second planetary gear sets are operatively connected to a double clutch device with a first and a second power shiftable clutch.

The term “operatively connected” means that two transmission elements for torque transmission can be directly connected to one another, or that further transmission elements are located between two transmission elements for torque transmission, for example one shaft or several shafts or gears. Two gearwheels that are in meshing engagement with one another are provided for transmitting a torque and a speed from one gearwheel to the other gearwheel. A gear is to be understood as meaning, for example, a sun gear, a ring gear and a planet gear of a planetary gear set.

A double clutch device is to be understood as a device with two power-shiftable clutches. Furthermore, the term “load-shiftable clutch” is to be understood as a device which has at least one open and one closed state and can be switched between the at least two states under load. in the In the open state, the clutch does not transmit any torque.

Advantageous exemplary embodiments are claimed in the subclaims and are explained in more detail below.

In a preferred embodiment, a sun gear of the other planetary gear stage can be coupled non-rotatably to a planetary gear carrier of one planetary gear stage via the second clutch and non-rotatably coupled to a ring gear of one planetary gear stage via the first clutch.

In addition, it can be expedient if the planetary gear carrier of the first planetary gear set or the planetary gear carrier of the second planetary gear set is fixed or received in a fixed / non-rotatable / stationary manner in a housing.

According to an advantageous development, the sun gear of one planetary gear set and the ring gear of the other planetary gear set can be operatively connected to the differential stage.

The drive device according to the invention thus allows great flexibility in the design of the gear structure, which makes it easier to adapt the desired gear ratio and spread without unnecessarily complicating the gear structure.

A pitch circle diameter of the sun gear of the first planetary gear set can preferably correspond to a pitch circle diameter of the sun gear of the second planetary gear set. That is, the pitch circle diameter of the sun gear of the first planetary gear set is equal to the pitch circle diameter of the sun gear of the second planetary gear set. This configuration enables the manufacture of the two sun gears to be simplified.

Particularly preferably, the sun gear of the first planetary gear set and the sun gear of the second planetary gear set can be arranged or formed on a common shaft, whereby the number of parts and thus the assembly effort can also be reduced.

In addition, it is advantageous if a pitch circle diameter of the ring gear of the first planetary gear set corresponds to a pitch circle diameter of the ring gear of the second planetary gear set. With the same pitch circle diameters of the ring gears or the sun gears of the first and second planetary gear sets, essentially identical planet gears can be used for both planetary gear sets, which increases the number of identical parts used and thus reduces manufacturing costs.

Furthermore, an advantageous embodiment can also be characterized in that an additional reduction gear is arranged in the torque flow between the electric drive machine and the differential stage. The reduction gear can be arranged on the input side between the electric drive machine and the first planetary gear stage or on the output side between the second planetary gear stage and the differential stage. The additional reduction gear increases the spread of the transmission device and can be designed, for example, as a spur gear stage or as a further planetary gear stage.

The first and second clutch of the double clutch device can preferably be designed as a friction clutch. Furthermore, the two couplings can preferably be arranged coaxially to one another. In particular, the respective clutch can be actuated by a respective actuator in order to initiate opening or closing of the respective clutch. The actuator can be implemented hydraulically, electromechanically, electromagnetically or, for example, also pneumatically.

It is useful here if opening both clutches can realize a power cut-off at the same time. Closing the first clutch and opening the second clutch can realize a first gear ratio, whereas closing the second clutch and opening the first clutch can realize a second gear ratio. In order to ensure that the shifting process from one clutch to the other clutch is largely free of tractive force interruption, one clutch can open in a transitional period while the other closes. Via the slip in the clutches, designed as friction clutches, a torque-free switchover between two gear stages can take place, which can be perceived by the operator of the drive device as a switchover mode between two gear stages without traction, which in turn increases the shifting comfort for the operator of the drive device. The first gear ratio is preferably not the same as the second gear ratio. For example, the first gear ratio can be greater than the second gear ratio. Alternatively, the first gear ratio can be smaller than the second gear ratio.

Furthermore, the electric drive machine preferably has a stator and a rotor, the rotor being non-rotatably connected to the drive shaft. The drive shaft can be designed as a rotor shaft or there is an axial offset between the drive shaft and the rotor shaft, with one Torque transmission device (reduction gear) can be arranged between the two shafts.

Furthermore, the differential stage is preferably designed as a spur gear differential, the differential stage being provided to distribute a drive power of the drive machine to a first and a second output shaft.

The drive machine can be arranged coaxially or axially parallel to the differential stage. The drive shaft is preferably arranged coaxially with at least one, in particular two, output shaft (s). In particular, the drive shaft is designed as a hollow shaft, with at least one of the two output shafts being guided axially through the drive shaft. The two output shafts are preferably arranged on a common drive axle. Alternatively, the drive shaft is arranged axially parallel to the two output shafts, with axially parallel meaning that there is an axial offset between the drive shaft and the output shafts.

In other words, the invention relates to a two-speed transmission for electric axles with a sun-ring gear connection. In the search for transmissions for two gears with an advantageous ratio distribution in an axially parallel and coaxial arrangement, the aim is to provide the simplest possible transmission structure with many identical parts and a suitable ratio distribution or spreading through a combination of two planetary gear stages with a spur gear stage and a shifting element designed as a double clutch or synchro unit, whereby the basic structure of the transmission has a sun-ring gear connection. In a first possible axially parallel configuration with a centrally arranged switching element, a high gear ratio can be achieved with a moderate spread. Optionally, an additional spur gear stage, for example designed as a spur gear differential, can be placed both upstream and downstream, which in turn increases the translation that can be implemented. A second axially parallel configuration with a centrally arranged switching element and optional, upstream or downstream spur gear stage enables a high gear ratio with increased spread. Here, too, the translation can be increased by possibly adjusting the spur gear stage before or after.

• 1 ein erstes Ausführungsbeispiel einer erfindungsgemäßen Antriebsvorrichtung,
• 2 eine Modifikation der Antriebsvorrichtung gemäß dem ersten Ausführungsbeispiel,
• 3 ein zweites Ausführungsbeispiel einer erfindungsgemäßen Antriebsvorrichtung, und
• 4 eine Modifikation der Antriebsvorrichtung gemäß dem zweiten Ausführungsbeispiel.

Further measures improving the invention are shown in more detail below together with the description of preferred exemplary embodiments of the invention with reference to the figures. The figures each show a simplified schematic representation to illustrate the structure of drive devices according to the invention. Show it:

• 1 a first embodiment of a drive device according to the invention,
• 2 a modification of the drive device according to the first embodiment,
• 3 a second embodiment of a drive device according to the invention, and
• 4th a modification of the drive device according to the second embodiment.

The figures are merely of a schematic nature and serve exclusively for the understanding of the invention. The same elements are provided with the same reference symbols. The features of the individual exemplary embodiments can be interchanged with one another.

1 shows a first embodiment of the drive device according to the invention 1 in axially parallel design.

The drive device according to the invention 1 for a motor vehicle - not shown here - has an electric drive machine - not shown here - and a transmission device 3 on. The electric drive machine has a stator and a rotor. A drive power (torque) of the electric drive machine is generated via a drive shaft 2 that is between the electric prime mover and the transmission device 3 is arranged and designed as a rotor shaft, in the transmission device 3 initiated.

The transmission device 3 comprises a first and second planetary gear set 4th , 5 as well as a differential stage 6th . The first planetary gear stage 4th has a first planetary gear set with a plurality of planetary gears 7a on which rotatable on a first planet carrier 8a are arranged and with a first sun gear 9a as well as with a first ring gear 10a are in mesh. So the planet gears mesh 7a of the first planetary gear set radially between the first sun gear 9a and the first ring gear 10a . The second planetary gear stage 5 has a second planetary gear set with several planetary gears 7b on which rotatable on a second planet carrier 8b are arranged and with a second sun gear 9b as well as with a second ring gear 10b are in mesh. So the planet gears mesh 7b of the second planetary gear set radially between the second sun gear 9b and the second ring gear 10b .

There is also a double clutch device 11 with a first clutch 12a and a second clutch 12b intended. Closing the first clutch 12a and opening the second clutch 12b realizes a first gear ratio, with a closing of the second clutch 12b and opening the first clutch 12a a second gear ratio realized. The first gear ratio is not the same as the second gear ratio. By opening both clutches 12a , 12b a power shutdown is implemented.

In other words, by shifting the dual clutch device 11 optionally that from the electric drive machine via the transmission device 3 on the differential stage 6th transmitted torque can be varied between the first and the second gear ratio. The torque transmitted in this way is ultimately used by the differential stage 6th on output shafts 13a , 13b which are connected, for example, to drive wheels of the motor vehicle. The transmission device 3 thus essentially enables two-speed operation of the motor vehicle.

As in 1 can be seen is in the drive device 1 according to the first exemplary embodiment, on the input side in the torque flow between the drive shaft 2 and the transmission device 3 an additional reduction gear designed as a spur gear stage 15th interposed. This means that the torque from the prime mover is transmitted via the drive shaft 2 and the reduction gear 15th into the transmission device 3 initiated. In addition, the reduction gear enables 15th a decoupling of the speeds of the drive shaft 2 and the transmission device 3 so that the electric drive machine, essentially independent of the transmission device 3 , can be operated at optimum speed.

In the drive device 1 according to the first embodiment is also the first sun gear 9a via the second clutch 12b rotatably with the second planet carrier 8b connectable. In addition, the first sun gear 9a over the first clutch 12a with the second ring gear 10b be coupled. Ie depending on the circuit of the double clutch device 11 can be the torque flow through the transmission device 3 changed and thus, as mentioned above, switched between the first and second gear ratio.

Furthermore is the first planet carrier 8a in the first embodiment fixed / non-rotatable in a housing 14th fixed or recorded. The transmission device 3 is thus over the first planet carrier 8a in the case 14th supported. The first ring gear 10a and the second sun gear 9b are also non-rotatably connected to one another and this non-rotatable composite consists of the first ring gear 10a and the second sun gear 9b is in turn with the differential stage 6th effectively connected. The torque is thus generated from the first ring gear via the non-rotatable assembly 10a and the second sun gear 9b from the transmission device 3 diverted and to the differential stage 6th which in turn transmit the torque to the two output shafts 13a , 13b .

2 shows a modification of the drive device according to the invention 1 according to the first embodiment. Only the differences to the one in 1 illustrated drive device 1 received according to the first embodiment.

As in 2 It can be seen that, on the output side, the additional reduction gear designed as a spur gear stage can be seen 15th in the torque flow from the electric drive machine to the output shafts 13a , 13b between the second planetary gear stage 5 and the differential stage 6th arranged.

Due to the reduction gear arranged on the output side 15th has the drive device 1 According to the modification of the first exemplary embodiment, it also has an axially parallel basic structure / construction, ie the drive shaft 2 is radially offset to the two output shafts 13a , 13b arranged.

5 shows a second embodiment of the drive device according to the invention 1 in axially parallel design. The main differences to the one in 1 illustrated drive device 1 received.

In contrast to the in 1 The first embodiment shown is the torque of the electric drive machine in the second embodiment via the drive shaft 2 , the reduction gear connected on the input side 15th onto the first ring gear, which is arranged or formed in a rotationally fixed manner on an input shaft 10a transfer. The first ring gear 10a can also in the second embodiment via the first clutch 12a rotatably with the second sun gear 9b be coupled.

The second clutch 12b in the second exemplary embodiment again enables a rotationally fixed coupling between the first planetary gear carrier 8a and the second sun gear 9b . The first sun gear 9a is non-rotatably with the second ring gear 10b connected and this non-rotatable connection is on the output side for torque output with the differential stage 6th effectively connected. In the second embodiment, the transmission device 3 over the permanently stationary in the housing 14th fixed second planet carrier 8b in the case 14th supported.

4th shows a modification of the invention Drive device 1 according to the second embodiment. Only the differences to the one in 3 illustrated drive device 1 received according to the second embodiment.

As in 4th It can be seen that, on the output side, the additional reduction gear designed as a spur gear stage can be seen 15th in the torque flow from the electric drive machine to the output shafts 13a , 13b between the second planetary gear stage 5 and the differential stage 6th arranged.

Due to the reduction gear arranged on the output side 15th has the drive device 1 According to the modification of the second exemplary embodiment, it also has an axially parallel basic structure / construction, ie the drive shaft 2 is in turn offset radially to the two output shafts 13a , 13b arranged.

List of reference symbols

1

Drive device

2

drive shaft

3

Transmission device

4th

first planetary gear stage

5

second planetary gear stage

6th

Differential stage

7a, 7b

Planetary gear

8a, 8b

Planetary gear carrier

9a, 9b

Sun gear

10a, 10b

Ring gear

11

Double clutch device

12a, 12b

coupling

13a, 13b

Output shaft

14th

casing

15th

Reduction gear

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• DE 102011088668 A1 [0002]
• DE 102004024086 A1 [0003]

Claims (9)

Drive device (1) for a motor vehicle, comprising an electric drive machine which is operatively connected to a transmission device (3) via a drive shaft (2), the transmission device (3) having at least a first and second planetary gear stage (4, 5) and a differential stage ( 6), and wherein the first and second planetary gear sets (4, 5) are operatively connected to a double clutch device (11) with a first and a second power shift clutch (12a, 12b), characterized in that a sun gear (9a, 9b) a planetary gear set (4, 5) and a ring gear (10a, 10b) of the other planetary gear set (4, 5) are connected to one another in a rotationally fixed manner. Drive device (1) according to Claim 1 , characterized in that a sun gear (9a, 9b) of the other planetary gear set (4, 5) with the interposition of the second clutch (12b) non-rotatably with a planetary gear carrier (8a, 8b) of the one planetary gear set (4, 5) and with the interposition of the first Coupling (12a) is non-rotatably coupled to a ring gear (10a, 10b) which has a planetary gear set (4, 5). Drive device (1) according to one of the preceding Claims 1 or 2 , characterized in that the planetary gear carrier (8a) of the first planetary gear set (4) or the planetary gear carrier (8b) of the second planetary gear set (5) is fixed in a stationary manner in a housing (14). Drive device (1) according to one of the preceding Claims 1 to 3 , characterized in that the sun gear (9a, 9b) of one planetary gear stage (4, 5) and the ring gear (10a, 10b) of the other planetary gear stage (4, 5) is operatively connected to the differential stage (6). Drive device (1) according to one of the preceding claims, characterized in that opening both clutches (12a, 12b) realizes a power cut-off. Drive device (1) according to one of the preceding claims, characterized in that closing the first clutch (12a) and opening the second clutch (12b) realizes a first gear ratio, with closing the second clutch (12b) and opening the first Coupling (12a) realized a second gear ratio. Drive device (1) according to Claim 6 , characterized in that the first gear ratio is not equal to the second gear ratio. Drive device (1) according to one of the Claims 1 to 7th , characterized in that an additional reduction gear (15) is arranged in the torque flow between the electric drive machine and the differential stage (6). Drive device (1) according to one of the preceding Claims 1 to 8th , characterized in that the drive machine is arranged offset axially parallel to the differential stage (6).

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