DRIVE ASSEMBLY HAVING AN ELECTRIC DRIVE AND TRANSMISSION

Abstract

A drive assembly comprises at least an electric drive having a drive shaft, and a transmission having at least one input shaft, wherein a drive power of the electric drive can be transmitted to the input shaft via the drive shaft, and can be transmitted from the input shaft into the transmission. The drive shaft and the input shaft are coaxial to one another and are interconnected by way of a toothing that is form-fitting at least in a circumferential direction. The drive shaft and the input shaft are at least frictionally connected at least in relation to an axial direction at least via a press fit formed in each case between an inner circumferential surface and an outer circumferential surface which are parallel to an axis of rotation, or the drive shaft and the input shaft together form a form-fitting connection via a connecting element.

Claims

1.-14. (canceled)

15. A drive assembly, comprising: an electric drive having a drive shaft; and a transmission having at least one input shaft; wherein a drive power of the electric drive is transmissible to the input shaft via the drive shaft and from the input shaft to the transmission; wherein the drive shaft and the input shaft are arranged coaxially with one another and are connected to one another by a first form-locking connection by way of a toothing system which is connected in a circumferential direction; and wherein the drive shaft and the input shaft are at least connected with respect to an axial direction by at least one of (a) a press fit formed between an inner circumferential surface and an outer circumferential surface which are parallel to an axis of rotation, or (b) the drive shaft and the input shaft together forming a second form-locking connection via a connecting element.

16. The drive assembly of 15, wherein the connecting element is a screw and has a thread which interacts with a mating thread on one of the drive shaft and the input shaft to form the second form-locking connection.

17. The drive assembly of claim 15, wherein the second form-locking connection between the connecting element and one of the drive shaft and the input shaft is arranged within the other of the input shaft and the drive shaft in a radial direction.

18. The drive assembly of claim 15, wherein the drive shaft or the input shaft is supported on a housing of the drive assembly via a first stop with respect to the axial direction, wherein a minimum distance between (a) the second form-locking connection between the connecting element and one of the drive shaft and the input shaft, and (b) the first stop, is at least 20% of a maximum length of the shaft which forms the second form-locking connection.

19. The drive assembly of claim 15, wherein the input shaft extends along the axial direction between a first input shaft end and a second input shaft end, wherein the drive shaft extends along the axial direction between a first drive shaft end and a second drive shaft end; wherein the first input shaft end is arranged within the drive shaft or the second drive shaft end is arranged within the input shaft and forms the press fit or, with the connecting element, the second form-locking connection.

20. The drive assembly of claim 19, wherein the connecting element can be arranged in the drive shaft via the first drive shaft end or in the input shaft via the second input shaft end to form the second form-locking connection.

21. The drive assembly of claim 20, wherein the connecting element is supported on the drive shaft or on the input shaft on a second stop with respect to the axial direction, wherein the second stop is arranged outside the respective shaft at the first drive shaft end or the second input shaft end, or is arranged within the respective shaft.

22. The drive assembly of claim 19, further comprising a multi-part housing having a first housing part and a second housing part, wherein the electric drive is arranged with the drive shaft in the first housing part and the transmission is arranged with the input shaft in the second housing part, wherein the first input shaft end can be inserted into the drive shaft or the second drive shaft end can be inserted into the input shaft to connect the housing parts.

23. The drive assembly of claim 22, wherein the input shaft is rotatably mounted in the second housing part or the drive shaft is rotatably mounted in the first housing part via two rolling bearings arranged at a distance from one another along the axial direction.

24. The drive assembly of claim 22, wherein the drive shaft is rotatably mounted in the first housing part or the input shaft is rotatably mounted in the second housing part via only one rolling bearing.

25. The drive assembly of claim 22, wherein the first housing part and the second housing part are fluidically separated from one another by at least one first seal arranged between the input shaft and the second housing part.

26. The drive assembly of claim 22, wherein the first housing part and the second housing part are fluidically separated from one another by at least one second seal arranged between the input shaft and the drive shaft.

27. The drive assembly of claim 15, wherein the drive shaft consists of an unhardened material or is at least partially hardened only at an inner circumferential surface, and the input shaft is fully hardened.

28. A motor vehicle, comprising: an axle and a drive train for driving at least the axle; wherein the drive train includes: an electric drive having a drive shaft; and a transmission having at least one input shaft; wherein a drive power of the electric drive is transmissible to the input shaft via the drive shaft and from the input shaft to the transmission; wherein the drive shaft and the input shaft are arranged coaxially with one another and are connected to one another by a first form-locking connection by way of a toothing system which is connected at least in a circumferential direction; and wherein the drive shaft and the input shaft are at least connected \with respect to an axial direction by at least one of (a) a press fit formed between an inner circumferential surface and an outer circumferential surface which are parallel to an axis of rotation, or (b) the drive shaft and the input shaft together forming a second form-locking connection via a connecting element.

Description

BRIEF SUMMARY OF THE DRAWINGS

[0048] Further explanation is provided in greater detail with reference to the figures. It should be noted that the exemplary embodiments shown are not intended to restrict the claimed invention. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and insights from the present description and/or figures. Identical reference signs denote identical objects, and therefore it may be possible to use explanations from other figures in addition. The figures are schematic and

[0049] FIG. 1: shows a first embodiment of the drive assembly in a side view in section;

[0050] FIG. 2: shows a second embodiment of the drive assembly in a side view in section;

[0051] FIG. 3: shows a third embodiment of the drive assembly in a side view in section;

[0052] FIG. 4: shows a fourth embodiment of the drive assembly in a side view in section;

[0053] FIG. 5 shows a fifth embodiment of the drive assembly in a side view in section;

[0054] FIG. 6: shows a motor vehicle.

DESCRIPTION

[0055] FIG. 1 shows a first embodiment of the drive assembly 1 in a side view in section. The drive assembly 1 comprises an electric drive 2 having a drive shaft 3 and a transmission 4 having an input shaft 5. The drive shaft 3 and the input shaft 5 are arranged coaxially with one another and are connected to one another by way of a toothing system 7 which is positively connected at least in a circumferential direction 6. The drive shaft 3 and the input shaft 5 are at least nonpositively connected with respect to an axial direction 8 via a press fit 12 formed between an inner circumferential surface 10 parallel to an axis of rotation 9 and an outer circumferential surface 11 parallel to the axis of rotation 9.

[0056] The drive assembly 1 additionally has a multi-part housing 19 having a first housing part 27 and a second housing part 28, wherein the electric drive 2 is arranged with the drive shaft 3 in the first housing part 27 and the transmission 4 is arranged with the input shaft 5 in the second housing part 28. To connect the housing parts 27, 28, the first input shaft end 22 can be inserted into the drive shaft 3. The input shaft 5 is rotatably mounted in the second housing part 28 via two rolling bearings 29 arranged at a distance from one another along the axial direction 8. An installation position of the input shaft 5 is fixed or determined (with respect to the radial direction 17 and with respect to the axial direction 8) by the arrangement of the rolling bearings 29.

[0057] As a result of the mounting of the input shaft 5 in the second housing part 28, functional testing of the transmission 4 can take place even without the drive 2, the drive shaft 3 and the first housing part 27.

[0058] The drive shaft 3 is rotatably mounted in the first housing part 27 via just one rolling bearing 29. The drive shaft 3 is connected to the input shaft 5 in such a way that the drive shaft 3 is also fixed in position with respect to the axial direction 8 via the input shaft 5 fixed in position with respect to the housing 19. In particular, positional fixing with respect to the radial direction 17 or coaxial arrangement of the input shaft 5 and of the drive shaft 3 is accomplished at least by means of the connection of the two shafts 3, 5, that is to say in particular by means of the press fit 12. Fixing of the position with respect to the axial direction 8 is accomplished in particular by means of the press fit 12 or the positive connection 14, which is illustrated in FIGS. 2 and 3. The drive shaft 3 is mounted on the first housing part 27 via a non-locating bearing.

[0059] The first housing part 27 and the second housing part 28 are fluidically separated from one another by means of a first seal 30 (in this case a shaft sealing ring) arranged between the input shaft 5 and the second housing part 28. This enables the second housing part 28 with the transmission 4 arranged therein and the associated lubrication and the input shaft 5 to be sealed off fluidtightly from the first housing part 27. Furthermore, the second housing part 28 can thus be produced and tested in fully functional form without the need for assembly with the drive 2 and the first housing part 27.

[0060] The input shaft 5 extends along the axial direction 8 between a first input shaft end 22 and a second input shaft end 23, wherein the first input shaft end 22 is arranged within the drive shaft 3 and forms the press fit 12 and the positive toothing system 7.

[0061] To assemble the drive assembly 1, the second housing part 28 with transmission 4 and input shaft 5 is made available. The first housing part 27 with the drive 2 and the drive shaft 3 is made available and pushed onto the second housing part 28 along the axial direction 8, wherein the input shaft 5 centers the drive shaft 3 by means of the outer circumferential surface 11 via the inner circumferential surface 10. During this process, the first input shaft end 22 is inserted into the drive shaft 3. The shafts can be displaced relative to one another along the axial direction 8 by means of an assembly tool 36, which can be inserted into the drive shaft 3 via a first drive shaft end 24. The assembly tool 36 interacts with the first input shaft end 22 via a threaded connection and is supported on the first drive shaft end 24. As a result of the rotation of the assembly tool 36, the drive shaft 3 can be pushed onto the input shaft 5 via the threaded connection to the input shaft 5 and thus the press fit 12 can be formed. During this process, the drive shaft 3 can be pushed against a stop of the input shaft 5, wherein a preload can be set, for example, by means of spring elements between the drive shaft 3 and the stop of the input shaft 5. Furthermore, a displacement path of the drive shaft 3 along the input shaft 5 during assembly can be shortened or adjusted, for example by means of washers arranged on the stop. The assembly tool 36 can be removed after the arrangement and connection of the housing parts 27, 28 to the housing 19.

[0062] FIG. 2 shows a second embodiment of the drive assembly 1 in a side view in section. Attention is drawn to the explanations of FIG. 1.

[0063] In contrast to the first embodiment, a positive connection 14 with respect to the axial direction between the connecting element 13 and the first input shaft end 22 is provided here in addition to the press fit 12 and the toothing system 6 which provides a positive connection with respect to the circumferential direction 6. The positive connection 14 is formed via a thread 15 of the connecting element 13 and a mating thread 16 of the input shaft 5.

[0064] The drive shaft 3 extends from a first drive shaft end 24 and along the axial direction 8 toward the input shaft 5 up to a second drive shaft end 25, wherein the connecting element 13 can be arranged in the drive shaft 3 via the first drive shaft end 24 to form the positive connection 14. The arrangement of the connecting element 13 via the first drive shaft end 24 makes it possible for the shafts 3, 5 to be slid into one another for the assembly of the transmission 4 and the drive 2 and, after the assembly is carried out in this way, to be fixed in position with respect to one another by means of the connecting element 13.

[0065] The connecting element 13 is supported on the drive shaft 3 on a second stop 26 with respect to the axial direction 8, wherein the second stop 26 is arranged within the drive shaft 3 (in this case on a shoulder on the inner circumferential surface 10 of the drive shaft 3).

[0066] The input shaft 5 is supported via a first stop 18 on a housing 19 (the second housing part 28) of the drive assembly 1 with respect to an axial direction 8 (in this case via the bearing inner ring of the rolling bearing 29), wherein a minimum distance 20 (along the axial direction 8) between [0067] the positive connection 14 between the connecting element 13 and the input shaft 5 and [0068] the first stop 18
is approximately 50% of a maximum length 21 of the input shaft 5 forming the positive connection 14 (between the first input shaft end 22 and the second input shaft end 23).

[0069] Owing to the distance 20 between the first stop 18 and the positive connection 14, an elasticity of the input shaft 5 can be exploited for the operation or assembly of the drive assembly 1. In particular, a prestress or preload of the shafts 3, 5 can be set in this way, wherein the adjustable prestress increases with increasing distance 20 and thus increasing available elasticity of the input shaft 5.

[0070] The connecting element 13 can be arranged in the drive shaft 3 via the first drive shaft end 24 to form the positive connection 14. The arrangement of the connecting element 13 via the first drive shaft end 24 makes it possible for the shafts 3, 5 to be slid into one another for the assembly of the transmission 4 and the drive 2 and, after the assembly is carried out in this way, to be fixed in position with respect to one another by means of the connecting element 13.

[0071] FIG. 3 shows a third embodiment of the drive assembly 1 in a side view in section. Attention is drawn to the explanations of FIGS. 1 and 2.

[0072] In contrast to the second embodiment, the connecting element 13 is supported on the drive shaft 3 on a second stop 26 with respect to the axial direction 8, wherein the second stop 26 is arranged outside the drive shaft 3 on the first drive shaft end 24. Thus, when there is trapped stress in the drive shaft 3 and the input shaft 5, the elasticity of the input shaft 5 (the distance 20) and of the connecting element 13 can be exploited.

[0073] Furthermore, the first housing part 27 and the second housing part 28 are in this case fluidically separated from one another by means of a second seal 31 (in this case an O-ring) arranged between the input shaft 3 and drive shaft 5. In addition, a third seal 35 is arranged between the connecting element 13 and the drive shaft 3.

[0074] FIG. 4 shows a fourth embodiment of the drive assembly 1 in a side view in section. FIG. 5 shows a fifth embodiment of the drive assembly 1 in a side view in section. FIGS. 4 and 5 are described jointly below. Attention is drawn to the explanations of FIG. 3.

[0075] In contrast to FIG. 3, the arrangement of the components comprising the drive 2 and the transmission 4 has been swapped here, i.e. the drive shaft 3 extends along the axial direction 8 between a first drive shaft end 24 and a second drive shaft end 25, while the second drive shaft end 25 is arranged within the input shaft 5 and forms the press fit 12 and the positive toothing system 7. In addition to the press fit 12 and the toothing system 7 which provides a positive connection with respect to the circumferential direction 6, a positive connection 14 with respect to the axial direction 8 between the connecting element 13 and the second drive shaft end 25 is furthermore provided. The positive connection 14 is formed by means of a thread 15 of the connecting element 13 and a mating thread 16 of the drive shaft 3. The connecting element 13 extends into the input shaft 5 via a second input shaft end 23 and is connected to the second drive shaft end 25 via the positive connection 14.

[0076] Furthermore, the connecting element 13 is supported on the input shaft 5 on a second stop 26 with respect to the axial direction 8, wherein the second stop 26 is arranged outside the input shaft 5 on the second input shaft end 23.

[0077] In the fourth embodiment according to FIG. 4, the drive shaft 3 is supported via a first stop 18 (and via a rolling bearing 29, the input shaft 5 and a further rolling bearing 29) on a housing 19 (in this case the second housing part 28) of the drive assembly 1 with respect to the axial direction 8.

[0078] In the fifth embodiment according to FIG. 5, the drive shaft 3 is supported via a first stop 18 (via the input shaft 5 and a rolling bearing 29) on a housing 19 (in this case the second housing part 28) of the drive assembly 1 with respect to the axial direction 8.

[0079] In the fourth embodiment according to FIG. 4, the connecting element 13 also extends beyond the second input shaft end 23 in the radial direction 17 and forms a stop for the inner ring of the rolling bearing 29.

[0080] FIG. 6 shows a motor vehicle 32 having at least two axles 33 with wheels and a drive train 34 for driving an axle 33, wherein the drive train 34 has the drive assembly 1.

LIST OF REFERENCE SIGNS

[0081] 1 drive assembly [0082] 2 drive [0083] 3 drive shaft [0084] 4 transmission [0085] 5 input shaft [0086] 6 circumferential direction [0087] 7 toothing system [0088] 8 axial direction [0089] 9 axis of rotation [0090] 10 inner circumferential surface [0091] 11 outer circumferential surface [0092] 12 press fit [0093] 13 connecting element [0094] 14 connection [0095] 15 thread [0096] 16 mating thread [0097] 17 radial direction [0098] 18 first stop [0099] 19 housing [0100] 20 minimum distance [0101] 21 maximum length [0102] 22 first input shaft end [0103] 23 second input shaft end [0104] 24 first drive shaft end [0105] 25 second drive shaft end [0106] 26 second stop [0107] 27 first housing part [0108] 28 second housing part [0109] 29 rolling bearing [0110] 30 first seal [0111] 31 second seal [0112] 32 motor vehicle [0113] 33 axle [0114] 34 drive train [0115] 35 third seal [0116] 36 assembly tool