Drive unit and vehicle

Abstract

The invention relates to a drive unit (1) for a vehicle (20), having a reducing group (4) and a main gearbox (5), wherein at least two electric machines (7.1, 7.2) are mounted on the reducing group (4) and each act on a separate torque path (8.1, 8.2) which in each case is in engagement with one of two main shafts (9.1, 9.2) in the main gearbox (5), wherein on each of the main shafts (9.1, 9.2) at least two idler gears (Z1 to Z4) run which are configured for engagement in a fixed gear (Z5, Z6) running on a countershaft (10) of the main gearbox (5), wherein each of the fixed gears (Z5, Z6) is configured for engagement with in each case one of the idler gears (Z1 to Z4) of each of the main shafts (9.1, 9.2), wherein each of the fixed gears (Z5, Z6) is configured for engagement with in each case one of the idler gears (Z1 to Z4) of each of the main shafts (9.1, 9.2) with the same transmission ratio.

Description

[0001] Daimler Truck AG Kanmogne Kwouossu

[0002] December 12, 2023

[0003] Drive unit and vehicle

[0004] The invention relates to a drive unit for a vehicle according to the preamble of claim 1 and a vehicle according to claim 9.

[0005] DE 102013218454 A1 describes a transmission, in particular a dual-clutch transmission, for a motor vehicle, comprising at least two partial transmissions, each of the partial transmissions comprising at least one input shaft, and an output shaft being arranged as the output shaft of both partial transmissions, the at least one input shaft being arranged on an input shaft axis and the output shaft being arranged on the input shaft axis or on a countershaft axis, in particular parallel to the input shaft axis, and a countershaft being arranged with at least one countershaft, the at least one countershaft being arranged on the countershaft axis, and a plurality of shifting devices being arranged, and at least one of the input shafts being connectable to the output shaft by means of at least two gear planes and / or at least one shifting element of one of the shifting devices.wherein two solid shafts on the input shaft axis can be coupled directly via a switching element, and wherein on the countershaft axis either a) a switching device comprising a single switching element is arranged, or wherein b) a switching device comprising two switching elements is arranged, which is connected to a countershaft designed as a hollow shaft, wherein the countershaft interacts with at least two gear planes, which has transmission elements on the same shaft on the input shaft axis, or that c) two or more switching devices are arranged.

[0006] The invention is based on the object of providing a novel drive unit for a vehicle and a novel vehicle. This object is achieved according to the invention by a drive unit for a vehicle having the features of claim 1 and by a vehicle having the features of claim 9.

[0007] Advantageous embodiments of the invention are the subject of the subclaims.

[0008] A drive unit for a vehicle according to the invention comprises a reduction group and a main transmission, wherein at least two electric machines are mounted on the reduction group, each acting on its own torque path, which engages with one of two main shafts in the main transmission, wherein at least two idler gears run on each of the main shafts and are configured to engage with one of at least two fixed gears running on a countershaft of the main transmission, wherein each of the fixed gears is configured to engage with one of the idler gears of each of the main shafts. According to the invention, each of the fixed gears is configured to engage with one of the idler gears of each of the main shafts with the same gear ratio. For example, the even-numbered gears of the main transmission can be realized on one of the main shafts and the odd-numbered gears on the other.The solution according to the invention enables the multiple use of the same gear wheel variants, whereby main shafts of the same design can be used.

[0009] In one embodiment, the gear ratio of one of the idler gears of each main shaft to the respective associated fixed gear is the inverse of the gear ratio of the other of the idler gears of the same main shaft to the respective associated fixed gear. This allows the number of gear variants used to be further reduced.

[0010] In one embodiment, the ratio between the two torque paths of the reduction group is one gear step. Thus, the overall gear ratio from one of the electric motors to the countershaft differs from the overall gear ratio from the other electric motor to the countershaft. This means that, despite identical gear ratios, different overall gear ratios are achieved by shifting the idler gears of both main shafts, for example, for a first and second gear, or for a third and fourth gear. In one embodiment, both torque paths each have an identically designed drive pinion, with the electric motors engaging the respective drive pinion with differently sized output pinions. This results in just five gear variants.

[0011] In one embodiment, the countershaft is connected to a rear-mounted group that has at least two shift positions with different gear ratios. This doubles the number of selectable gears. This can be used to differentiate between different types of use, for example, off-road and on-road.

[0012] In one embodiment, the rear-mounted group comprises a planetary gear with a sun gear, a ring gear, and a planetary gear set. The sun gear is locked to the ring gear in one of the gear positions, so that the planetary gear set rotates with a gear ratio of one. This gear position can be used particularly for on-road applications. Because no gears rotate in the rear-mounted group, the drive unit is very efficient in power transmission.

[0013] In one embodiment, at least one power take-off can be arranged on the drive unit, in particular on an output gear of at least one of the electric machines and / or on a drive gear of at least one of the torque paths of the reduction group and / or on one of the idler gears of the main transmission.

[0014] In one embodiment, a retarder can be connected to the drive unit, in particular to a cardan shaft at an output of the drive unit.

[0015] According to one aspect of the present invention, a vehicle is proposed, comprising at least one driven axle and a drive unit as described above, wherein the drive unit is connected to the axle via a cardan shaft at an output of the drive unit.

[0016] In one embodiment, the vehicle may be designed as a commercial vehicle.

[0017] By adapting the reduction group, electric machines with different characteristics and sizes can be applied without redesigning the entire drive unit. The inventive solution allows for multiple gear types to be used. In particular, both main shafts can be designed identically.

[0018] The drive unit according to the invention covers two application cases differentiated by the rear-mounted group, for example off-road, characterized by driving characteristics, and on-road, characterized by efficiency.

[0019] The drive unit according to the invention is suitable, for example, for construction vehicles of various sizes (high variance, e.g., 20 to 120 tons). The drive unit is sequentially powershiftable for each application.

[0020] Embodiments of the invention are explained in more detail below with reference to drawings.

[0021] Showing:

[0022] Fig. 1 is a schematic view of an embodiment of a drive unit for a vehicle,

[0023] Fig. 2 is a schematic view of another embodiment of a drive unit for a vehicle, and

[0024] Fig. 3 is a schematic view of a vehicle.

[0025] Corresponding parts are provided with the same reference numerals in all figures.

[0026] Figure 1 is a schematic view of an embodiment of a drive unit 1 for a vehicle 20 (shown in Figure 3), which is particularly suitable for heavy commercial vehicles capable of both off-road and on-road operation. The drive unit 1 is mounted via a cardan shaft 2 to an axle 3, for example, the rear axle, of the vehicle 20 with the appropriate gear ratio. In this configuration, the drive unit 1 can, for example, drive vehicles with a total mass of 20 to 120 tons.

[0027] The axle 3 can, for example, have a differential gear 14. The drive unit 1 is, for example, geometrically stepped and has three subassemblies, namely a reduction group 4, a main gearbox 5, and a secondary gearbox 6. At least two electric motors 7.1, 7.2 are mounted on the reduction group 4. The outputs of these electric motors 7.1, 7.2 are guided by the reduction group 4 in two separate torque paths 8.1, 8.2 and transformed to a desired speed / torque ratio. The two separate torque paths 8.1, 8.2 then lead to the main gearbox 5. The main gearbox 5 has two main shafts 9.1, 9.2 and a countershaft 10.

[0028] The main shafts 9.1, 9.2 differ in that all even-numbered gears G2, G4 are located on one of the main shafts 9.2 and all odd-numbered gears G1, G3 are located on the other main shaft 9.1. In the main gearbox 5, pairs of one of the even-numbered gears G2 and G4 and one of the odd-numbered gears G1 and G3 have the same gear ratio and engage with the same fixed gear Z5, Z6 on the countershaft 10. This arrangement allows the main gearbox 5 to be shifted completely sequentially and without any interruption in the load. Both main shafts 9.1, 9.2 can be designed exactly the same, so that identical parts can be used. The countershaft 10 then transfers the shared torque to the rear-mounted group 6. The rear-mounted group 6 has two shift positions: Low (short gear ratio) and High (long gear ratio). The Low switch position is intended for off-road operation and for operation with high tonnages for starting.The high shift position is primarily intended for on-road use. The rear-mounted group 6 features a planetary gear set with a sun gear 11, a ring gear 12, and a planetary gear set 13. In the high shift position, the sun gear 11 is locked to the ring gear 12, and the planetary gear set 13 rotates at a gear ratio of one.

[0029] In particular, two identically designed electrical machines 7.1, 7.2 can be provided. Furthermore, the electrical machines 7.1, 7.2 can be designed to directly drive the reduction group 4 or with a reduction gear for driving it. It is also conceivable for one of the electrical machines 7.1 to be designed for direct drive and the other with a reduction gear for driving it. The characteristics of the electrical machines 7.1, 7.2 can be designed such that their peak power corresponds to approximately 70% of their continuous power. The reduction group 4 transforms torques and speeds to an input of the main gearbox 5. The special feature here is that the ratio between the two torque paths 8.1, 8.2 of the reduction group 4 is that of a gear step. This means that if the drive pinions of the torque paths 8.1, 8.2 are identical, the output pinions of the electrical machines 7.1, 7.2 are different sizes (a total of three different gears).This has the effect that in the main transmission 5, the ratio of the first and second gears G1, G2, on the one hand, and the ratio of the third and fourth gears G3, G4, on the other, are identical, whereby the ratio of the third and fourth gears G3, G4 can be the inverse of the ratio of the first and second gears G1, G2. The four gears G1, G2, G3, G4 each have a pair of two gears, one of which runs as an idler gear Z1 to Z4 on the respective main shaft 9.1, 9.2, and another as a fixed gear Z5, Z6 on the countershaft 10.This theoretically results in eight gears, but the number can be reduced to six by using on the countershaft 10 one and the same gear designed as a fixed gear Z5 with a gear designed as an idler gear Z1 for the first gear G1 and a gear designed as an idler gear Z2 for the second gear G2, and on the other hand one and the same gear designed as a fixed gear Z6 with a gear designed as an idler gear Z3 for the third gear G3 and a gear designed as an idler gear Z4 for the fourth gear G4. The same gear ratio for the first and second gears G1, G2 on the one hand and the third and fourth gears G3, G4 on the other hand enables double tooth meshing in the fixed gears Z5, Z6 with an identical center distance. In this way, two gears are saved. The remaining six gears are represented by only two gear variants.

[0030] This means that three gear variants for the reduction group 4 and two gear variants for the main transmission 5 result in a total of five gear variants. The countershaft 10 extends into the switchable planetary gear set 13. This serves to cover the required range of driving characteristics for a vehicle 20 that is to be driven in both off-road and on-road operation.

[0031] The Low gear position (short gear ratio) covers off-road use, especially for starting on loose surfaces, at high approach angles, and / or steep inclines. The High gear position (long gear ratio = 1) is used primarily for on-road use. Because no gears are rotating in this position, drive unit 1 is very efficient in power transmission.

[0032] The drive unit 1 according to the invention can be configured with five gear variants and a planetary gear system to provide eight gears, including four off-road gears and four on-road gears. In an exemplary embodiment, gears with the following number of teeth n are used, resulting in the corresponding gear ratios i:

[0033] - Output gear of the electric machine 7.1: n=27

[0034] - Drive wheel of torque path 8.1: n=102

[0035] Gear ratio of the torque path 8.1: i=3.788

[0036] - Output gear of the electric machine 7.2: n=27

[0037] - Drive wheel of torque path 8.2: n=53

[0038] Gear ratio of the torque path 8.2: i=1 ,988

[0039] - Idler gear Z1 , Z2: n=26

[0040] Fixed gear Z5: n=49

[0041] Gear ratio of gears G1 and G2: i=1 ,884

[0042] Idler gear Z3, Z4: n=49

[0043] Fixed gear Z5: n=26

[0044] Gear ratio of gears G3 and G4: i=0.510

[0045] - Ring gear 12: n=90

[0046] Sun gear: 11: n=25

[0047] Planetary gear set: n=31

[0048] Gear ratio in shift position Low: i=4.6

[0049] Gear ratio in switching position High: i=1

[0050] Figure 2 is a schematic view of the drive unit 1 with exemplary power take-offs mPTO.

[0051] The drive unit 1 can be provided with one or more power take-offs mPTO (in particular engine, transmission, side, axial PTO), which can be engaged with:

[0052] - an output gear of at least one of the electrical machines 7.1, 7.2,

[0053] - a drive wheel of at least one of the torque paths 8.1, 8.2 of the reduction group 4, and / or

[0054] - one of the idler gears Z1 to Z4 of the main gearbox 5.

[0055] Furthermore, a retarder R can be provided, which can, for example, be in engagement with the propeller shaft 2.

[0056] Figure 3 is a schematic view of a vehicle 20, for example a commercial vehicle, in particular a heavy commercial vehicle, which may have the driven axle 3 and the drive unit 1 described above, wherein the drive unit 1 is connected to the axle 3 via the cardan shaft 2.

[0057] List of reference symbols

[0058] 1 Drive unit Cardan shaft Axle Reduction group Main gearbox Rear group

[0059] 7.1 electrical machine

[0060] 7.2 electrical machine

[0061] 8.1 Torque path

[0062] 8.2 Torque path

[0063] 9.1 Main shaft

[0064] 9.2 Main shaft

[0065] 10 Countershaft

[0066] 11 Sun gear

[0067] 12 ring gear

[0068] 13 Planetary gear set

[0069] 14 differential gears

[0070] 20 vehicles

[0071] G1 Gang

[0072] G2 Gear

[0073] G3 Gear

[0074] G4 speed mPTO power take-off

[0075] R Retarder

[0076] Z1 to Z4 idler gear

[0077] Z5, Z6 fixed gear

Claims

Patent claims 1. Drive unit (1) for a vehicle (20), comprising a reduction group (4) and a main transmission (5), wherein at least two electric machines (7.1, 7.2) are mounted on the reduction group (4), each acting on its own torque path (8.1, 8.2), which is in engagement with one of two main shafts (9.1, 9.2) in the main transmission (5), wherein at least two idler gears (Z1 to Z4) run on each of the main shafts (9.1, 9.2), which idler gears are configured to engage a fixed gear (Z5, Z6) running on a countershaft (10) of the main transmission (5), wherein each of the fixed gears (Z5, Z6) is configured to engage with one of the idler gears (Z1 to Z4) of each of the main shafts (9.1, 9.2), characterized in that each of the fixed gears (Z5, Z6) is configured to engage with one of the idler gears (Z1 to Z4) of each of the main shafts (9.1, 9.2), characterized in that each of the fixed gears (Z5, Z6) is configured to engage with one of the idler gears (Z1 to Z4) each of the main shafts (9.1, 9.2) is configured with the same transmission ratio.

2. Drive unit (1) according to claim 1, characterized in that the transmission ratio of one of the idler gears (Z1 to Z4) of each of the main shafts (9.1, 9.2) to the respectively associated fixed gear (Z5, Z6) is the inverse of the transmission ratio of the other of the idler gears (Z1 to Z4) of the same main shaft (9.1, 9.2) to the respectively associated fixed gear (Z5, Z6).

3. Drive unit (1) according to claim 1 or 2, characterized in that the ratio of a gear step lies between the two torque paths (8.1, 8.2) of the reduction group (4).

4. Drive unit (1) according to claim 3, characterized in that both torque paths (8.1, 8.2) each have an identically designed drive pinion, wherein the electrical machines (7.1, 7.2) engage with the respective drive pinion with output pinions of different sizes.

5. Drive unit (1) according to one of the preceding claims, characterized in that the countershaft (10) is connected to a rear-mounted group (6) which has at least two switching positions with different transmission ratios.

6. Drive unit (1) according to claim 5, characterized in that the rear-mounted group (6) has a planetary gear with a sun gear (11), a ring gear (12) and a planetary gear set (13), wherein the sun gear (11) is locked to the ring gear (12) in one of the switching positions, so that the planetary gear set (13) rotates with the transmission ratio of one.

7. Drive unit (1) according to one of the preceding claims, characterized in that at least one power take-off (mPTO) is arranged on the drive unit (1), in particular on an output gear of at least one of the electrical machines (7.1, 7.2) and / or on a drive gear of at least one of the torque paths (8.1, 8.2) of the reduction group (4) and / or on one of the idler gears (Z1 to Z4) of the main transmission (5).

8. Drive unit (1) according to one of the preceding claims, characterized in that a retarder (R) is connected to the drive unit (1), in particular to a cardan shaft (2) at an output of the drive unit (1).

9. Vehicle (20) comprising at least one driven axle (3) and a drive unit (1) according to one of the preceding claims, characterized in that the drive unit (1) is connected to the axle (3) via a cardan shaft (2) at an output of the drive unit (1).

10. Vehicle (20) according to claim 9, characterized in that the vehicle (20) is designed as a commercial vehicle.

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