Transmission device for a motor vehicle

Abstract

A transmission device for a motor vehicle, having an input shaft, which is operatively connectable to a drive device of the motor vehicle, and a first output shaft and a second output shaft, and comprising a spur gear differential transmission which is designed as a planetary transmission, by means of which the input shaft is coupled to the first output shaft and the second output shaft. It is provided that the spur gear differential transmission comprises a first sun gear coupled to the first output shaft and a second sun gear coupled to the second output shaft, wherein the first sun gear meshes with a first planet gear which is rotatably mounted on a planet gear carrier coupled to the input shaft, which first planet gear also meshes with a second planet gear which is likewise rotatably mounted on the planet gear carrier and which meshes with the second sun gear.

Claims

1. A transmission device for a motor vehicle, comprising: an input shaft, which is operatively connectable to a drive device of the motor vehicle, and a first output shaft and a second output shaft, and comprising a spur gear differential transmission which is designed as a planetary transmission, by means of which the input shaft is coupled to the first output shaft and the second output shaft, wherein the spur gear differential transmission comprises a first sun gear coupled to the first output shaft and a second sun gear coupled to the second output shaft, wherein the first sun gear meshes with a first planet gear which is rotatably mounted on a planet gear carrier coupled to the input shaft, which first planet gear also meshes with a second planet gear which is likewise rotatably mounted on the planet gear carrier and which meshes with the second sun gear; wherein an electric machine is coupled across a coupling planetary transmission to a shifting device and an input gear.

2. The transmission device according to claim 1, wherein the first planet gear is present as a first stepped planetary gear, which is rotatably mounted to a second stepped planetary gear, which can be coupled to the input shaft and to the electric machine.

3. The transmission device according to claim 2, wherein the second stepped planetary gear meshes with a gear that is connected to an intermediate shaft.

4. The transmission device according to claim 3, wherein the electric machine can be coupled by means of the shifting device to the input shaft or the intermediate shaft.

5. The transmission device according to claim 3, wherein the electric machine is coupled rotationally firmly in a first shifting position of the shifting device to the input shaft and in a second shifting position to the intermediate shaft.

6. The transmission device according to claim 5, wherein the shifting device comprises a first output gear coupled to the input shaft, a second output gear coupled rotationally firmly to the intermediate shaft and wherein the input gear coupled rotationally firmly to the electric machine, wherein a coupling element of the shifting device, in the first shifting position, meshes with the first output gear and the input gear and is disengaged from the second output gear and, in the second shifting position, meshes with the second output gear and the input gear and is disengaged from the first output gear.

7. The transmission device according to claim 1, wherein the input shaft is arranged coaxially to the first output shaft and/or the second output shaft.

8. The transmission device according to claim 1, wherein the spur gear differential transmission is designed with no ring gear.

9. The transmission device according to claim 1, wherein the coupling planetary transmission is a two-step type and connects the electric machine to the input gear and a further input gear of the shifting device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure shall now be explained more closely below with the aid of the exemplary embodiments presented in the drawing, without this being a limitation of the invention. There are shown:

(2) FIG. 1 a schematic representation of a transmission device for a motor vehicle in a first embodiment,

(3) FIG. 2 a schematic representation of the transmission device in a second embodiment, and

(4) FIG. 3 a schematic representation of the transmission device in a third embodiment.

DETAILED DESCRIPTION

(5) FIG. 1 shows a schematic representation of a first embodiment of a transmission device 1, which is provided here for example as part of a motor vehicle 2 not shown in detail. The motor vehicle 2 has a wheel axle 3 with a first partial shaft 4 and a second partial shaft 5. The wheel axle 3 or the partial shafts 4 and 5 can be driven across the transmission device 1 by means of a drive device of the motor vehicle 2. The drive device is or at least can be operatively connected to an input shaft 6 of the transmission device 1. The first partial shaft 4, on the other hand, is connected to a first output shaft 7, and the second partial shaft 5 to a second output shaft 8 of the transmission device 1, or they are operatively connected to the respective output shaft 7 or 8.

(6) The operative connection between the first partial shaft 4 and the first output shaft 7 is produced by a first transmission 9, the operative connection between the second partial shaft 5 and the second output shaft 8 by a second transmission 10. The transmissions 9 and 10 may be in the form of angle gear transmissions. Preferably, they are designed as a bevel gear transmission and accordingly they each possess a first bevel gear 11 or 12 and a second bevel gear 13 or 14. According to the present embodiment of the transmission device 1 here, it may be provided that the partial shafts 4 and 5 or their axes of rotation in the lateral or radial direction are offset from each other relative to the axes of rotation. However, alternatively, the partial shafts 4 and 5 may also be arranged coaxial to each other, i.e., aligned with each other at least in a top view.

(7) The output shafts 7 and 8 may be angled relative to the partial shafts 4 and 5 or the wheel axle 3, i. e., making with it an angle of more than 0° and less than 180°, such as an angle of 90°. The corresponding deflection is realized with the aid of the transmissions 9 and 10, which are in the form of angle transmissions. Of course, alternatively, the transmissions 9 and 10 may be designed as spur gear transmissions. For example, the output shafts 7 and 8 in this case are arranged parallel to the partial shafts 4 and 5.

(8) The transmission device 1 comprises a spur gear differential transmission 15, by which the first output shaft 7 and the second output shaft 8 are operatively connected or coupled permanently to the input shaft 6. For this purpose, the spur gear differential transmission 15 is designed as a planetary transmission, having a first sun gear 16, a second sun gear 17 and a planet gear carrier 18, on which a first planet gear 19 and a second planet gear 20 are rotatably mounted. The planet gear carrier 18 is coupled to the input shaft 6 of the transmission device 1, especially in rigid and/or permanent manner. The first sun gear 16, on the other hand, is coupled to the first output shaft 7, and the second sun gear 17 is coupled to the second output shaft 8, preferably in rigid and/or permanent manner. The first planet gear 19 meshes with the second planet gear 20, preferably in permanent manner. The first planet gear 19 furthermore meshes with the first sun gear 16, but not with the second sun gear 17. The second planet gear 20, on the other hand, meshes with the second sun gear 17, but not with the first sun gear 16.

(9) The first planet gear 19 is designed as a first stepped planetary gear 21, which is coupled rotationally firmly to a second stepped planetary gear 22. The two stepped planetary gears 21 and 22 are together mounted rotatably on the planet gear carrier 18, being present preferably on opposite sides of a bearing location 23 on the planet gear carrier 18. The second stepped planetary gear 22 is rotationally firmly coupled to an intermediate shaft 24, especially in rigid and/or permanent manner. It can clearly be seen that the two output shafts 7 and 8 as well as the input shaft 6 and the intermediate shaft 24 are arranged coaxial to each other, i.e., they have the same axis of rotation. The second output shaft 8 here accommodates the first output shaft 7 at least for a portion, and likewise the intermediate shaft 24 accommodates the input shaft 6 at least for a portion. It should further be pointed out in particular that the spur gear differential transmission 15 is a design without ring gear, i.e., it has no ring gear.

(10) The transmission device 1 comprises an electric machine 25, which can be coupled by a shifting device 26 to the input shaft 6 and/or the intermediate shaft 24. The shifting device 26 comprises a coupling element 27, which can move according to the double arrow 28 in the axial direction. In the embodiment represented here, the shifting device 26 comprises an input gear 29, a first output gear 30 and a second output gear 31. Furthermore, an auxiliary gear 32 may be provided.

(11) The coupling element 27, now, is configured such that it can mesh permanently with the input gear 29 of the shifting device 26. In a first shifting position, it meshes additionally with the first output gear 30, but not with the second output gear 31 or the auxiliary gear 32. In a second shifting position, on the other hand, it meshes additionally with the second output gear 31, but not with the first output gear 30 or the auxiliary gear 32. In a third shifting position, it meshes additionally with the auxiliary gear 32, but not with the two output gears 30 and 31.

(12) The input gear 29 is coupled to the electric machine 25, preferably in rigid and/or permanent manner. The first output gear 30 is firmly coupled to the input shaft 6 and the second output gear 31 firmly to the intermediate shaft 24, likewise preferably in rigid and/or permanent manner. The auxiliary gear 32, on the other hand, is decoupled from both the input shaft 6 and the intermediate shaft 24 and accordingly is mounted free to turn.

(13) The connection between the electric machine 25 and the shifting device 26 or the input gear 29 is via a coupling planetary transmission 33. This comprises a sun gear 34, a planet gear carrier 35 with planet gear 36 mounted rotatably on it, and a ring gear 37. The sun gear is coupled to the electric machine 25, preferably in rigid and/or permanent manner. The ring gear 37, on the other hand, is stationary. The planet gear 36 now meshes both with the sun gear 34 and with the ring gear 37. The planet gear carrier 35 is coupled to the shifting device 26, especially the input gear 29, particularly in rigid and/or permanent manner.

(14) With the aid of the shifting device 26, the electric machine 25 can be coupled either to the input shaft 6 or the intermediate shaft 24. In the former case, the electric machine 25 can provide a torque, which is superimposed on a torque provided by the drive device on the input shaft 6. In this case, therefore, the driving torque can be increased or decreased with the aid of the electric machine 25.

(15) In the second shifting position of the shifting device 26, on the other hand, the electric machine 25 can be used to provide a “torque vectoring” functionality. In this mode, the driving torque present on the input shaft 6 can be divided between the two partial shafts 4 and 5 by providing an additional torque with the aid of the electric machine 25, namely, in such a way that a desired torque distribution is established between them. This means that, with the aid of the electric machine 25, the driving torque can be freely apportioned on the output shafts 7 and 8 and hence on the partial shafts 4 and 5.

(16) FIG. 2 shows a schematic representation of the transmission device 1 in a second embodiment. This is basically similar in configuration to the first embodiment, so that in the following only the differences shall be discussed, otherwise referring to the preceding remarks. The differences lie in the design of the shifting device 26. Whereas in the case of the first embodiment the input gear 29 was designed as a ring gear, it is now present as a spur gear and it is situated between the first output gear 30 and the second output gear 31, looking in the axial direction. However, the functionality is identical to the shifting device 26 of the above described first embodiment. As compared to this, the auxiliary gear 32 may be omitted, as is the case here.

(17) FIG. 3 shows a third embodiment of the transmission device 1 in a schematic representation. Once again, reference is made to the preceding remarks, especially those for the first embodiment, and the differences shall be pointed out in the following. These lie in the fact that the coupling planetary transmission 33 is a two-step type, so that the electric machine 25 is coupled across the coupling planetary transmission 33 to both the input gear 29 and to a further input gear 38, preferably in rigid and/or permanent manner. For this, the coupling planetary transmission 33 comprises a further sun gear 39, a further planet gear 40 and a further ring gear 41.

(18) The sun gear 39 is coupled to the sun gear 34 and hence to the electric machine 25, preferably in rigid and/or permanent manner. The planet gear 40 is mounted rotatably on the planet gear carrier 35, yet is independent of the planet gear 36. The planet gear 40 meshes on the one hand with the sun gear 39 and on the other hand with the ring gear 41. The ring gear is rotatably mounted and coupled to the input gear 38, preferably in rigid and/or permanent manner. The planet gears 36 and 40 preferably have different numbers of teeth, so that a first gearing can be established between the electric machine 25 and the input gear 29 and a second gearing between the electric machine 25 and the further input gear 38, the two gearings being different from each other.

(19) In addition to the shifting positions already described above, a fourth shifting position of the shifting device 26 may now exist, in which the coupling element 27 meshes with the input gear 38 instead of the input gear 29, while at the same time it meshes with the first output gear 30. Accordingly, a different gearing can established between the electric machine 25 and the input shaft 6 than that in the first shifting position.

(20) The described transmission device 1 has the advantage, in particular, that the spur gear differential transmission 15 is designed with no ring gear and accordingly can be realized with slight axial design space. Furthermore, the shifting device 26 makes possible a flexible attachment of the electric machine 25, either for driving the input shaft 6 or for providing the “torque vectoring” functionality by driving the intermediate shaft 24.