Drive system for a motor vehicle, and motor vehicle having such a drive device

Abstract

The invention relates to a drive system (3) for a motor vehicle (1), comprising an electric machine (5) and a differential gear (7), wherein the electric machine (5) is coaxial to a drive axis (9) of the drive system (3), and the electric machine (5) is torque-transmittingly connected to the differential gear (7) via two gear meshing points (11, 11') which are rotatable about an axis of rotation (13) parallel to and offset from the drive axis (9).

Description

[0001] Daimler Truck AG 1 Furkan Özvatan

[0002] 30.10.2025

[0003] Drive device for a motor vehicle and motor vehicle with such a drive device

[0004] The invention relates to a drive device for a motor vehicle and a motor vehicle with such a drive device.

[0005] Especially in electrically powered vehicles, the optimal arrangement of drive components presents a significant challenge. The high-voltage batteries used to power such drives, in particular, require considerable space within the chassis, while other chassis components—such as air suspension or brakes—significantly restrict the remaining installation space. One approach is to arrange two electric motors parallel to each other and offset from the drive axle, but this requires a very large amount of installation space. Alternatively, it has been suggested that two electric motors be arranged coaxially, and especially coaxially with the drive axle, but this limits the overall length of each individual electric motor and thus their power output.

[0006] The invention is therefore based on the objective of creating a drive device for a motor vehicle and a motor vehicle with such a drive device, wherein the aforementioned disadvantages are at least reduced, preferably do not occur.

[0007] The problem is solved by providing the present technical teaching, in particular the teaching of the independent claims as well as the preferred embodiments disclosed in the dependent claims and the description.

[0008] The problem is solved, particularly in a first aspect, by creating a drive device for a motor vehicle comprising an electric motor and a differential gear, wherein the electric motor is arranged coaxially to a drive axle of the drive device, and wherein the electric motor is connected to the differential gear via two gear engagements rotatable about an axis of rotation offset parallel to the drive axle, thus transmitting torque. Advantageously, the drive device has a small installation space, while at the same time the connection of the electric motor via the two Daimler Truck AG 2 Furkan Özvatan

[0009] October 30, 2025: The gear meshing represents a direct, simple, and efficient coupling with low gearbox losses. Furthermore, the drive device requires few components and is therefore cost-effective.

[0010] In the context of the present technical teaching, the fact that the electric machine is arranged coaxially to the drive axis means in particular that a rotor axis of rotation, i.e. an axis about which a rotor of the electric machine is rotatably mounted, is arranged coaxially with the drive axis.

[0011] The drive axle can be an axis extending globally in the vehicle's Y-direction, i.e., in the lateral direction, when a motor vehicle with a drive device is arranged as intended on a horizontal driving plane. However, the drive axle can also be an axis extending obliquely to the driving plane – for example, halfway along the side – and running, for instance, from a differential gear located slightly higher geodesically to a wheel center located slightly lower geodesically.

[0012] In one embodiment, the electric machine is arranged coaxially to a drive shaft that connects a differential gear to a driven wheel in a torque-transmitting manner. In particular, the electric machine is arranged on the drive shaft, or the rotor's axis of rotation coincides with a drive shaft axis of rotation of the drive shaft, wherein the drive shaft is preferably rotatably mounted relative to the rotor of the electric machine, and thus is not directly driven by the rotor.

[0013] In the context of this technical teaching, an axis is generally understood to be an imaginary axis, in particular an axis of rotation, that is, a one-dimensional straight line extending along a specific direction. In contrast, a shaft is generally understood to be an extended, three-dimensional body made of at least one material, which is in particular arranged and configured to rotate about a specific axis, wherein the axis associated with the body is simultaneously a longitudinal and preferably an axis of symmetry of the body.

[0014] The drive axle can, in particular, be a wheel axle of the motor vehicle. In the context of this technical teaching, a wheel axle is understood to be, in particular, an axle on which, as intended, driven wheels of the motor vehicle having the drive device are or will be arranged; thus, the wheel axle is—when the drive device is arranged as intended on the motor vehicle—in particular a driven axle of the motor vehicle. Two or more wheels can, in particular, be mounted on the wheel axle. Daimler Truck AG 3 Furkan Özvatan

[0015] 30.10.2025 driven wheels, referred to as drive wheels, shall be arranged, preferably an even number of wheels symmetrically distributed on a left and right side in the direction of travel.

[0016] In one embodiment, the two gear engagements are each designed as a gear, with both gears being rotatable about the same common axis of rotation. The fact that this axis of rotation is offset parallel to the drive axis means, in the context of the present technical teaching, in particular that at least one projection of the axis of rotation onto an imaginary horizontal plane, for example, the driving plane, is aligned parallel to a projection of the drive axis onto the imaginary horizontal plane. In one embodiment, the axis of rotation and the drive axis are also oriented parallel to each other in three-dimensional space.

[0017] In one embodiment, the differential gear is arranged on the drive axle.

[0018] According to a further development of the invention, the electric machine is a first electric machine, wherein the drive device comprises a second electric machine arranged axially parallel to the first electric machine, wherein the drive device also comprises a transmission, and wherein the transmission is arranged and configured to connect the second electric machine to the differential gear in a torque-transmitting manner. In this way, both electric machines can be advantageously arranged in a space-saving manner, while at the same time not being significantly limited with regard to their overall length and thus their power output. In particular, a powerful second electric machine can be provided to the first electric machine as a booster.

[0019] In one embodiment, the first electric machine and the second electric machine have the same rated power, in particular the same rated power. In another embodiment, the first electric machine and the second electric machine have different rated powers. In particular, in one embodiment, it is possible for the first electric machine to have a higher rated power than the second electric machine. In this embodiment, the component with the largest space requirement is advantageously positioned precisely in the center of the installation space.

[0020] The fact that the gearbox is arranged and configured to connect the second electric machine to the differential in a torque-transmitting manner means, in particular, that the gearbox is arranged and configured to connect the second electric machine in Daimler Truck AG 4 Furkan Özvatan

[0021] 30.10.2025 to connect at least one gear of the manual transmission to the differential transmission in a torque-transmitting manner.

[0022] According to a further development of the invention, the drive device comprises a plurality of electric machines of varying power outputs, which can optionally be used as the second electric machine. Advantageously, in this case, the drive device is designed as a kit or modular system, in which the power output for the second electric machine can be configured as required by selecting from the plurality of electric machines. Alternatively, the second electric machine can also be omitted to achieve a particularly simple, space-saving, and cost-effective design.

[0023] According to a further development of the invention, the transmission is a two-speed transmission. This advantageously offers a space-saving, simple, cost-effective, yet efficient way to connect the second electric motor to the differential gear for torque transmission.

[0024] Advantageously, one gear of the two-speed transmission—for example, the first gear, without limiting generality—is designed such that the second electric motor can provide a high torque at the wheels during acceleration. Preferably, the other gear of the two-speed transmission—for example, the second gear, without limiting generality—is additionally designed such that the second electric motor can provide additional power at higher speeds, particularly on highways or freeways, for example, to overcome steep inclines.

[0025] According to a further development of the invention, the differential gear is a cage differential gear, wherein the electric machine – in particular the first electric machine – is torque-transmittingly connected to a differential cage of the cage differential gear. This represents a particularly simple, space-saving, reliable and cost-effective design.

[0026] According to a further development of the invention, a gearbox output of the transmission is connected to the differential cage in a torque-transmitting manner. This also represents a particularly simple, space-saving, reliable, and cost-effective design. In particular, the torques of the two electric motors can be added at the differential cage. Daimler Truck AG 5 Furkan Özvatan

[0027] 30.10.2025

[0028] The problem is also solved in a second aspect by creating a motor vehicle that has a drive device according to the invention or a drive device according to one or more of the embodiments described above. In connection with the motor vehicle, the advantages are particularly those already explained in connection with the drive device.

[0029] The installation space of the drive device preferably does not extend, or at least not significantly, beyond an imaginary cylinder whose axis of symmetry runs along the drive axis—or, in other words, between the imaginary centers of the drive wheels—where the imaginary circumferential area of ​​the imaginary cylinder is defined by the outer circumference of the drive wheels. This consideration demonstrates that the drive device is designed to be particularly space-saving, while still maintaining high performance, especially since the overall length of the electrical motors is not unnecessarily limited. The drive device thus exhibits a particularly high power density.

[0030] According to a further development of the invention, the motor vehicle is a commercial vehicle, in particular a truck or a bus. In these configurations, the advantages already mentioned are realized in a particularly effective way.

[0031] The invention will be explained in more detail below with reference to the drawing. The drawing shows:

[0032] Figure 1 shows a schematic detail representation of an embodiment of a motor vehicle with an embodiment of a drive device.

[0033] Fig. 1 shows a schematic detail representation of an embodiment of a motor vehicle 1 - specifically a region of its wheel axle 2 - with an embodiment of a drive device 3. The motor vehicle 1 can in particular be a commercial vehicle, preferably a truck or a bus.

[0034] The drive device 1 comprises a first electric machine 5 and a differential gear 7, wherein the first electric machine 5 is arranged coaxially to a drive axle 9 of the drive device 1, which here coincides with the wheel axle 2. The first electric machine 5 is connected to the differential gear 7 via two gear engagements 11, 1T, which are rotatable about a pivot axis 13 that is offset parallel to the drive axle 9, thus transmitting torque. In particular, the first electric machine 5 is arranged here on a drive shaft 14. Daimler Truck AG 6 Furkan Özvatan

[0035] 30.10.2025

[0036] The tooth engagements 11, 1 T are preferably each designed as a gear, and the two gears are rotatable about the same common axis of rotation 13.

[0037] The differential gear 7 is located here on the drive axle 9.

[0038] In the illustrated embodiment, the drive device 3 also includes a second electric machine 15 arranged parallel to the axis of the first electric machine 5, and a transmission 17 which is arranged and set up to connect the second electric machine 15 to the differential gear 7 in a torque-transmitting manner.

[0039] The transmission 17 is preferably a two-speed transmission, wherein preferably a first gear of the two-speed transmission 17 is designed such that the second electric machine 15 can provide a high torque to drive wheels 19, 19' of the motor vehicle 1 in the event of a starting process, and wherein a second gear of the two-speed transmission 17 is designed such that the second electric machine 17 can provide additional power at higher speeds, for example for overcoming steep inclines.

[0040] In the illustrated embodiment, the differential gear 7 is a cage differential gear with a differential cage 21, and the first electric machine 5 is connected to the differential cage 21 in a torque-transmitting manner. Furthermore, a gear output 23 of the transmission 17 is preferably connected to the differential cage 21 in a torque-transmitting manner.

[0041] It is possible that the drive device 3 includes a further electric machine 15 with a different power output, which can be selected as needed for the manufacture of the drive device 3. However, the second electric machine 15 can also be omitted to obtain a particularly simple, space-saving and cost-effective design of the drive device 3.

[0042] The installation space of the drive device 3 preferably does not extend, or at least not significantly, beyond an imaginary cylinder 25, which extends with its axis of symmetry along the wheel axis 2, wherein an imaginary circumferential area 27 of the imaginary cylinder 25 is defined by an outer circumference of the drive wheels 19, 19'. The drive device 3 is thus designed to be particularly space-saving, yet nevertheless—or precisely because of this—it exhibits a high power density, whereby, in particular, the installation length of the electric motors 5, 15 is not unnecessarily limited. Daimler Truck AG Furkan Özvatan

[0043] 30.10.2025

[0044] Reference symbol list

[0045] 1 motor vehicle

[0046] 2 wheel axle

[0047] 3 Drive device

[0048] 5 first electric machine

[0049] 7 Differential gears

[0050] 9 drive axle

[0051] 11, 1 T dental interventions

[0052] 13. Axis of rotation

[0053] 14 Plug shaft

[0054] 15 second electric machine

[0055] 17 manual transmissions

[0056] 19, 19' drive wheels

[0057] 21 Differential cage

[0058] 23 Gearbox output

[0059] 25 imaginary cylinders

[0060] 27 Circumferential area

Claims

Daimler Truck AG 8 Furkan Özvatan 30.10.2025 Patent claims 1. Drive device (3) for a motor vehicle (1), comprising an electric machine (5) and a differential gear (7), wherein the electric machine (5) is arranged coaxially to a drive shaft (9) of the drive device (3), wherein the electric machine (5) is connected to the differential gear (7) via two tooth engagements (11, 1 T) rotatable about a rotation axis (13) offset parallel to the drive shaft (9) in a torque-transmitting manner.

2. Drive device (3) according to claim 1, wherein the electric machine (5) is a first electric machine (5), wherein the drive device (3) has a second electric machine (15) arranged axially parallel to the first electric machine (5), wherein the drive device (3) also has a transmission (17), and wherein the transmission (17) is arranged and configured to connect the second electric machine (15) to the differential gear (7) in a torque-transmitting manner.

3. Drive device (3) according to claim 2, comprising a plurality of electric machines of different power, which can optionally be used as the second electric machine (15).

4. Drive device (3) according to one of claims 2 or 3, wherein the transmission (17) is a two-speed transmission.

5. Drive device (3) according to one of the preceding claims, wherein the differential gear (7) is a cage differential gear, and wherein the - first - electric machine (5) is connected to a differential cage (21) of the differential gear (7) in a torque-transmitting manner.

6. Drive device (3) according to one of claims 2 to 4, wherein the differential gear (7) is a cage differential gear, and wherein the first electric machine (5) is connected to a differential cage (21) of the differential gear (7) in a torque-transmitting manner, and wherein a gear output (23) of the transmission (17) is also connected to the differential cage (21) in a torque-transmitting manner.

7. Motor vehicle (1) with a drive device (3) according to one of claims 1 to 6. Daimler Truck AG 9 Furkan Özvatan 30.10.2025 8. Motor vehicle (1) according to claim 7, wherein the motor vehicle (1) is a commercial vehicle, in particular a truck or a bus.

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