DRIVE ARRANGEMENT

Description

State of the art

[0001] The invention relates to a drive arrangement according to the preamble of claim 1.

[0002] DE 10 2018 113 173 A1 discloses a transmission arrangement for an electric vehicle with an electrically shiftable two-speed transmission. The transmission arrangement comprises a first shaft and an output shaft. The first shaft has gears and a guide contour arranged therebetween. Two idler gears are arranged on the output shaft, each meshing with one of the gears, as well as a shift rod that can be moved back and forth to shift into a first and a second gear position. However, the first gear ratio, in particular, is limited by the two gear ratios.

[0003] A drive arrangement for a vehicle, with an electric machine and a two-stage spur gear, is known from DE 10 2018 129 931 A1. Disclosure of the invention

[0004] The problem underlying the invention is solved by a drive arrangement having the features of claim 1. Advantageous developments of the invention are mentioned in the subclaims.

[0005] The (electric) drive arrangement is particularly designed and / or intended as a drive arrangement for a vehicle. The drive arrangement comprises an electric machine and a two-stage spur gear transmission. The spur gear transmission has an input shaft, an intermediate shaft, a sideshaft, and an output shaft. The electric machine is connected to the input shaft so that the input shaft can be driven by the electric machine. The input shaft, the intermediate shaft, the sideshaft, and the output shaft are coupled to one another via spur gear stages in such a way that when driven by the electric machine in a first gear stage (first gear), the input shaft transmits torque to the output shaft via the sideshaft and the intermediate shaft, and in a second gear stage (second gear), the input shaft (without sideshaft) transmits torque directly to the output shaft via the intermediate shaft.In other words, the side shaft is bypassed in the second gear stage.

[0006] With a two-stage spur gear unit (two gears), a smaller electric motor can be used to meet the drive requirements. The electric motor can be operated more frequently at higher efficiency levels. This contributes to a compact design and efficient operation of the drive arrangement. Furthermore, a comparatively large gear ratio range (wide gear ratio spread) can be covered, since in the first gear stage, the load flow is routed across all four shafts (including the side shaft), whereas in the second gear stage, the load flow is routed across only three shafts (the side shaft is bypassed).

[0007] The drive arrangement can thus be used in vehicles requiring a high first gear ratio, which cannot be achieved with two spur gear stages (e.g., gear ratio i > 16). In this case, the proposed drive arrangement represents an extremely compact solution. The drive arrangement can be used, for example, in an off-road vehicle, which can achieve extreme climbing capabilities thanks to a high-ratio first gear stage (first gear).

[0008] The proposed (electric) drive arrangement can be used as an electric axle or as part of an electric axle (E-axle) in a partially electric or fully electric vehicle, e.g. a passenger car, an SUV or an off-road vehicle.

[0009] The drive arrangement may comprise a housing in which the electric machine and the spur gear are at least partially, preferably completely, arranged or enclosed.

[0010] The input shaft, the intermediate shaft, the side shaft and / or the output shaft can each be rotatably mounted in the drive arrangement by means of rolling bearings relative to a base, e.g. a housing of the drive arrangement. Irrespective of this, the input shaft can be the rotor shaft of the electric machine or a separate shaft which is rotationally fixedly coupled to the rotor shaft of the electric machine. According to a further development, the input shaft and the output shaft can be coupled to one another in such a way that when driven by the electric machine in an identical direction of rotation, the output shaft is driven in a first direction of rotation in the first switching stage and is driven opposite to the first direction of rotation in the second switching stage. In other words, the direction of rotation of the output shaft is reversed in the two switching stages when the direction of rotation of the electric machine or the input shaft is identical.In the first gear stage, the output shaft can rotate in the opposite direction to the input shaft. In the second gear stage, the output shaft can rotate in the same direction as the input shaft.

[0011] According to a further development, the sideshaft can be arranged between the input shaft and the intermediate shaft or between the intermediate shaft and the output shaft. This allows for a flexible arrangement of the intermediate shaft while maintaining essentially the same functionality, for example, to meet different installation space requirements.

[0012] According to the invention, the first shift stage (first gear) comprises a first spur gear stage with a first pinion and a first gear meshing with the first pinion. The first pinion is rotatably or non-rotatably coupled to the input shaft and / or arranged on the input shaft, and the first gear is non-rotatably or non-rotatably coupled to the side shaft and / or arranged on the side shaft. This allows a reliable spur gear stage to be realized using simple structural means.

[0013] According to the invention, the first shift stage (first gear) has a second spur gear stage with a second pinion and a second gear meshing with the second pinion, wherein the second pinion is rotatably or non-rotatably coupled to the side shaft and / or arranged on the side shaft, and wherein the second gear is non-rotatably or non-rotatably coupled to the intermediate shaft and / or rotatably mounted on the intermediate shaft. This also allows a reliable spur gear stage to be realized using simple structural means. The second gear is arranged as a fixed gear or as a loose gear on the intermediate shaft, which facilitates shiftability.

[0014] Optionally, the first gear stage (first gear), i.e., the first spur gear stage and the second spur gear stage, can be designed with straight teeth (the pinion and gear of the first and second spur gear stages each have straight teeth). This minimizes the bearing forces acting on the relevant rolling bearings, for example, when the first gear stage is used infrequently or for a short period of time, thus further simplifying the drive arrangement.

[0015] According to the invention, the second shift stage (second gear) has a third spur gear stage with a third pinion and a third gear meshing with the third pinion, wherein the third pinion is rotatably or non-rotatably coupled to the input shaft and / or arranged on the input shaft, and wherein the third gear is non-rotatably or non-rotatably coupled to the intermediate shaft and / or rotatably mounted on the intermediate shaft. This also allows a reliable spur gear stage to be realized using simple structural means. The third gear is arranged as a fixed gear or as a loose gear on the intermediate shaft, which facilitates shiftability.

[0016] According to the invention, a switching device that can be actuated by means of an actuator is arranged on the intermediate shaft, wherein the second gearwheel, which in this embodiment is rotatably coupled to the intermediate shaft, can be coupled to the intermediate shaft in a first switching position (first gear) by means of the switching device and / or the third gearwheel, which in this embodiment is rotatably coupled to the intermediate shaft, can be coupled to the intermediate shaft in a second switching position (second gear). This allows switching between the different switching stages or gears to be carried out using simple structural means. Only one switching device is required, which favors a design with a small number of components.

[0017] The shifting device or devices can each have a shifting element, e.g., a shift sleeve, which is non-rotatably coupled to the respective shaft (input shaft, side shaft, or intermediate shaft) but is movable along the central longitudinal direction of the respective shaft (input shaft, side shaft, or intermediate shaft). The actuator can be designed as a hydraulic, electric motor, or electromagnetic actuator. Optionally, a synchronization device can be arranged on the shifting device to compensate for speed differences. This allows the shifting times between the gear stages to be shortened.

[0018] According to the invention, the spur gear has a fourth spur gear stage (final drive) with a fourth pinion and a fourth gear meshing with the fourth pinion. The fourth pinion is non-rotatably coupled to the intermediate shaft and / or arranged on the intermediate shaft, and the fourth gear is non-rotatably coupled to the output shaft and / or arranged on the output shaft. This allows a spur gear stage for a final drive to be provided using simple design means.

[0019] According to a further development, the electric motor can be configured such that it is driven in a different direction of rotation in the first gear stage than in the second gear stage. This allows the output shaft to be driven in the same direction of rotation regardless of the selected gear stage. Particularly with moderate shift time requirements, the inherently different direction of rotation in the two gear stages or gears does not pose a problem, since the electric motor is decelerated during the shifting process and accelerated in the opposite direction of rotation before the other gear stage is engaged. As already indicated, a synchronization device on the shifting device can help compensate for speed differences.

[0020] According to a further development, the output shaft can have a differential.

[0021] This facilitates axle drive of a vehicle through the drive assembly, as speed differences caused, for example, by cornering can be compensated for at the wheels driven or driven by the drive assembly (drive wheels). The vehicle's drive wheels can be coupled to the differential via output shafts.

[0022] According to a further development, the spur gear can have a parking lock, wherein the parking lock can be arranged on the input shaft, on the intermediate shaft, or on the output shaft. This allows a parking lock function to be implemented using simple structural means. The parking lock can have, for example, a toothed parking lock gear and a parking lock pawl that can be brought into engagement with the parking lock gear to block the parking lock gear. The parking lock gear can be non-rotatably attached to one of the aforementioned shafts. The parking lock pawl can be attached to a base of the drive arrangement, for example, to a housing of the drive arrangement. The parking lock pawl is movable between a release position and a blocking position.

[0023] Possible embodiments of the invention are explained below with reference to the accompanying drawings. They show: Fig.1 a drive arrangement in a perspective view; Fig.2 a schematic view of the drive arrangement from Fig. 1 showing the load flow in the first switching stage; and Fig.3 a schematic view of the drive arrangement from Fig. 1 with representation of the load flow in the second switching stage.

[0024] A drive arrangement bears the reference numeral 10 in the figures. The drive arrangement 10 has an electric machine 12 and a two-stage spur gear 14.

[0025] The spur gear 14 has an input shaft 16, an intermediate shaft 18, a side shaft 20, and an output shaft 22, which are oriented parallel to each other in the example. These shafts are each rotatably mounted on the drive assembly 10, in particular on a housing (not shown) of the drive assembly 10, by means of rolling bearings 24. The rolling bearings 24 can be ball bearings, roller bearings, or tapered bearings.

[0026] The electric machine 12 is connected to the input shaft 16, so that the input shaft 16 can be rotationally driven by the electric machine 12. The input shaft 16 can be a separate shaft from the rotor shaft (not shown) of the electric machine 12, which is rotationally fixedly connected to the rotor shaft. In the example, the side shaft 20 is arranged between the input shaft 16 and the intermediate shaft 18.

[0027] The input shaft 16, the intermediate shaft 18, the side shaft 20 and the output shaft 22 are coupled to one another via spur gear stages in such a way that when driven by the electric machine 12 in a first switching stage 26, the input shaft 16 transmits a torque to the output shaft 22 via the side shaft 20 and the intermediate shaft 18 (cf. Fig.2 ) and that in a second switching stage 28 the input shaft 16 transmits a torque directly to the output shaft 22 via the intermediate shaft 18 (cf. Fig.3 ; side shaft 20 is bypassed).

[0028] In the example, the input shaft 16 and the output shaft 22 are coupled to one another in such a way that when driven by the electric machine 12 in the same direction of rotation, the output shaft 22 is driven in a first direction of rotation in the first switching stage 26 and is driven opposite to the first direction of rotation in the second switching stage 28 (cf. Fig.1 ).

[0029] The first shift stage 26 has a first spur gear stage 30 with a first pinion 32 and a first gear 34 meshing with the first pinion 32. The first pinion 32 is rotationally fixedly coupled to the input shaft 16 and arranged on the input shaft 16. The first gear 34 is rotationally fixedly coupled to the side shaft 20 and arranged on the side shaft 20. In the example, the first gear 34 has a larger diameter than the first pinion 32.

[0030] The first shift stage 26 has a second spur gear stage 40 with a second pinion 42 and a second gear 44 meshing with the second pinion 42. The second pinion 42 is rotationally fixedly coupled to the side shaft 20 and arranged on the side shaft 20. The second gear 44 is rotatably coupled to the intermediate shaft 18 and rotatably mounted on the intermediate shaft 18 (loose gear). In this example, the second pinion 42 has a smaller diameter than the first gear 34 and / or the second gear 44.

[0031] The second shift stage 28 has a third spur gear stage 50 with a third pinion 52 and a third gear 54 meshing with the third pinion 52. The third pinion 52 is non-rotatably coupled to the input shaft 16 and arranged on the input shaft. The third gear 54 is rotatably coupled to the intermediate shaft 18 and rotatably mounted on the intermediate shaft 18 (loose gear). In this example, the third gear 54 has a larger diameter than the third pinion 52.

[0032] A switching device 60, which can be actuated by means of an actuator (not shown), is arranged on the intermediate shaft 18. In a first switching position (first switching stage 26 engaged), the second gear 44 can be coupled or is coupled in a rotationally fixed manner to the intermediate shaft 18 by means of the switching device 60 (see FIG. Fig.2 ). In addition, by means of the switching device 60 in a second switching position (second switching stage 28 engaged), the third gear 54 can be coupled or is coupled in a rotationally fixed manner to the intermediate shaft 18 (cf. Fig.3 ).

[0033] In the example, the switching device 60 has a switching element 62, for example a shift sleeve, which is coupled in a rotationally fixed manner to the intermediate shaft 18, but is guided displaceably along the central longitudinal direction of the intermediate shaft 18 (cf. Fig.1 ). Regardless, the actuator (not shown) can be designed as a hydraulic, electric motor, or electromagnetic actuator. Optionally, a synchronization device can be arranged on the switching device 60 to compensate for speed differences, as explained above.

[0034] The spur gear 12 has a fourth spur gear stage 70 with a fourth pinion 72 and a fourth gear 74 meshing with the fourth pinion 72. The fourth pinion 72 is rotationally fixedly coupled to the intermediate shaft 18 and arranged on the intermediate shaft 18. The fourth gear 74 is rotationally fixedly coupled to the output shaft 22 and arranged on the output shaft 22. In the example, the fourth gear 74 has a larger diameter than the fourth pinion 72.

[0035] The electric machine 12 is configured such that it is driven in a different direction of rotation in the first switching stage 26 than in the second switching stage 28 (cf. Fig.2 and 3 ). This means that the output shaft 22 is driven in the same direction of rotation regardless of the selected gear stage (cf. Fig.2 and 3 ).

[0036] Optionally, the output shaft can have a differential, as explained above (not shown). The spur gear 14 has a parking lock 80, wherein the parking lock 80 is arranged on the input shaft 16 in the example (another arrangement is also conceivable, see above). The parking lock 80 has a parking lock gear 82, for example, toothed, which is connected in a rotationally fixed manner to the input shaft 16, and a parking lock pawl (not shown) that can be brought into engagement with the parking lock gear 82 to block the parking lock gear 82.

[0037] Fig.2 , to which reference has already been made in part, shows a schematic view of the drive arrangement 10 from Fig.1 with representation of the load flow in the first switching stage 26. For better clarity, the input shaft 16 and the side shaft 20 are shown separately from each other, whereby they mesh with each other in the drive arrangement 10 (cf. Fig.1 ).

[0038] As in Fig.2 As illustrated, the load flow in the first gear stage 26 (first gear) is directed via three spur gear stages 30, 40, 70 and thus via all four shafts 16, 18, 20, 22. The switching element 62 of the switching device 60 is brought into the first switching position (in Fig.2 pushed to the left), so that the second gear 44 (idler gear) is rotationally fixedly coupled to the intermediate shaft 18. When the electric machine 12 is driven, a torque is thus transmitted from the input shaft 16 via the first spur gear stage 30 of the first switching stage 26 to the side shaft 20 of the first switching stage 26 and from there via the second spur gear stage 40 of the first switching stage 26 to the intermediate shaft 18. Finally, the output shaft 22 is driven via the fourth spur gear stage 70.

[0039] Fig.3 , to which reference has also already been made in part, shows a schematic view of the drive arrangement 10 from Fig.1 with representation of the load flow in the second switching stage 18. Here too, for better clarity, the input shaft 16 and the side shaft 20 are shown separately from each other, whereby they mesh with each other in the drive arrangement 10 (cf. Fig.1 ).

[0040] As in Fig.3 As illustrated, the load flow in the second gear stage 28 (second gear) is guided via two spur gear stages 50, 70 and thus via only three shafts 16, 18, 22. The switching element 82 of the switching device 80 is brought into the second switching position (in Fig.3 pushed to the right), so that the third gear 54 (idler gear) is rotationally fixedly coupled to the intermediate shaft 18. When the electric machine 12 is driven, a torque is thus transmitted from the input shaft 16 via the third spur gear stage 50 of the second switching stage 28 to the intermediate shaft 18. Finally, the output shaft 22 is driven via the fourth spur gear stage 70.

[0041] As explained above, if the direction of rotation of the electric machine 12 or the input shaft 16 were identical in the first switching stage 26 and the second switching stage 28, the direction of rotation of the output shaft 22 would be reversed. This can be avoided by configuring the electric machine 12 such that it is driven in a different direction of rotation in the first switching stage 26 than in the second switching stage 28 (cf. Fig.2 and 3 ), as explained above.

[0042] In summary, the core of the invention is the use of a proposed drive arrangement 10 as or in an electric axle (E-axle) of a vehicle, taking into account the reversed directions of rotation and the use of the reversal of the direction of rotation of the electric machine for compensation.

[0043] The proposed drive arrangement 10 enables the realization of completely new gear ratio combinations in both gear stages or gears (e.g., an extremely high-ratio crawler gear for off-road vehicles or for operating heavy trailers). Any losses, if any, are only marginally higher than with conventional single-stage spur gears. Furthermore, the proposed drive arrangement 10 allows for a more cost-effective design than comparatively complex planetary gears.

Claims

1. Drive assembly (10), in particular for a vehicle, having an electric machine (12) and a two-stage spur gear mechanism (14), which has an input shaft (16), an intermediate shaft (18) and a side shaft (20), wherein the electric machine (12) is connected to the input shaft (16), so that the input shaft can be driven by the electric machine (12), wherein the input shaft (16), the intermediate shaft (18) and the side shaft (20) are coupled to each other in terms of gearing by means of spur gear stages (30, 40, 50), wherein a first shift stage (26) has a first spur gear stage (30) with a first pinion (32) and a first gear (34) meshing with the first pinion (32), wherein the first pinion (32) is rotatably or rotationally fixedly coupled to the input shaft (16) and wherein the first gear (34) is rotationally fixedly or rotatably coupled to the side shaft (20), wherein the first shift stage (26) has a second spur gear stage (40) with a second pinion (42) and a second gear (44) meshing with the second pinion (42), wherein the second pinion (42) is rotatably or rotationally fixedly coupled to the side shaft (20) and wherein the second gear (44) is rotationally fixedly or rotatably coupled to the intermediate shaft (18), wherein a second shift stage (28) has a third spur gear stage (50) with a third pinion (52) and a third gear (54) meshing with the third pinion (52), wherein the third pinion (52) is rotatably or rotationally fixedly coupled to the input shaft (16) and wherein the third gear (54) is rotationally fixedly or rotatably coupled to the intermediate shaft (18), characterized in that the two-stage spur gear mechanism (14) has an output shaft (22), wherein the spur gear mechanism (14) has a fourth spur gear stage (70) with a fourth pinion (72) and a fourth gear (74) meshing with the fourth pinion (72), wherein the fourth pinion (72) is rotationally fixedly coupled to the intermediate shaft (18), wherein the fourth gear (74) is rotationally fixedly coupled to the output shaft (20), wherein the input shaft (16), the intermediate shaft (18), the side shaft (20) and the output shaft are coupled to each other in terms of gearing by means of spur gear stages (30, 40, 50, 70) in such a way that, during driving by the electric machine (12), in the first shift stage (26) the input shaft (16) transmits torque to the output shaft (22) via the side shaft (20) and the intermediate shaft (18), and in that in the second shift stage (28) the input shaft (16) transmits torque directly to the output shaft (22) via the intermediate shaft (18), wherein a switching device (60) which can be actuated by means of an actuator is arranged on the intermediate shaft (18), wherein the second gear (44) can be rotationally fixedly coupled to the intermediate shaft (18) by means of the switching device (60) in a first switching position and wherein the third gear (54) can be rotationally fixedly coupled to the intermediate shaft (18) by means of the switching device (60) in a second switching position.

2. Drive assembly (10) according to Claim 1, characterized in that the input shaft (16) and the output shaft (22) are coupled to each other in such a way that, during driving by the electric machine (12) in the same direction of rotation, the output shaft (22) is driven in a first direction of rotation in the first shift stage (26) and is driven in the opposite direction to the first direction of rotation in the second shift stage (28).

3. Drive assembly (10) according to Claim 1 or 2, characterized in that the side shaft (20) is arranged between the input shaft (16) and the intermediate shaft (18) or between the intermediate shaft (18) and the output shaft (22).

4. Drive assembly (10) according to any of the preceding claims, characterized in that the electric machine (12) is designed in such a way that it is driven in a different direction of rotation in the first shift stage (26) than in the second shift stage (28).

5. Drive assembly (10) according to any of the preceding claims, characterized in that the output shaft (22) has a differential, and / or in that the spur gear mechanism (14) has a parking lock (80), wherein the parking lock (80) is arranged on the input shaft (16), on the intermediate shaft (18) or on the output shaft (22).