Electric drive system

Abstract

The invention relates to an electric drive system (1) having at least two at least partially separate drive trains, a first electric machine (2) and a second electric machine (3), wherein the drive trains can be coupled to the first or second electric machine (2, 3), respectively, wherein at least one cogwheel (18 to 21) is arranged for the coupling, wherein a plurality of shift elements (S1, S1'; S2, S2') are arranged for coupling at least one cogwheel (18 to 21) to the respective input shaft (4, 5) in order to selectively transmit its driving force to the respective output shaft (13), wherein the shift elements (S1, S1'; S2, S2') are configured to decouple the respective cogwheel (18 to 21) from the input shaft (4, 5) when the electric drive system (1) is operated in partial load with a power requirement below a certain threshold.

Description

Technical Field

[0001] The present invention relates to an electric drive system, particularly for motor vehicles, of the type detailed in the preamble of claim 1. Background Technology

[0002] In addition to hybrid drive systems that use both an internal combustion engine and an electric motor to drive the vehicle, pure electric drive systems are becoming increasingly important. These systems can include drive systems for purely electric axles, having gear ratios that can be shifted via a transmission, particularly having multiple gears. As prior art, this application references DE 10 2008002 380 A1. That patent discloses some features of the preamble to the current claims of this application, but unlike the present invention, it applies to hybrid drive systems rather than pure electric drive systems. Here, the structure includes a combined transmission with a main gearbox and a range gearbox, the range gearbox having a planetary gear set. Two electric motors are provided, each driving its respective input shaft of the main gearbox, while the internal combustion engine can drive the output shaft of the main gearbox via a shiftable clutch. The output shaft of the main gearbox is connected to the center gear of the planetary gear set of the range gearbox, whose planetary gear carrier is the output end of the hybrid drive system.

[0003] DE 10 2020 005 394 A1 describes an electric drive system having two motors and a combined transmission including a main gearbox and a range gearbox, wherein the range gearbox has a planetary gear set, wherein a first input shaft of the main gearbox is connected to or is capable of being connected to a first motor in such a way that torque can be introduced from the first motor into the combined transmission via the first input shaft, wherein a second input shaft of the main gearbox is also connected to or is capable of being connected to a second motor in such a way, wherein the output shaft of the main gearbox is connected to a first element of the planetary gear set in a manner that permanently transmits torque, and wherein a second element of the planetary gear set is connected to a driven shaft of the combined transmission in a manner that permanently transmits torque. Exactly two drive gears are arranged coaxially with the first input shaft, wherein exactly two additional drive gears are arranged coaxially with the second input shaft, wherein these two input shafts are connected to or are capable of being connected to the output shaft via exactly two fixed gears arranged coaxially with the output shaft, and wherein the first fixed gear is permanently meshed with the first and third drive gears, and the second fixed gear is permanently meshed with the second and fourth drive gears.

[0004] WO 2023 / 031206 A1 describes an electric drive system for a working machine, comprising a first electric motor having a first motor shaft and a second electric motor having a second motor shaft, and a shiftable transmission having a driven shaft, wherein the first motor shaft is a first input shaft of the transmission, and the second motor shaft is a second input shaft of the transmission. The first and second input shafts are parallel to each other with respect to the output shaft, but their distances from the output shaft are different from each other. Summary of the Invention

[0005] The objective of this invention is to provide an electric drive system having the features of the preamble of claim 1, which enables comfortable and long-lasting operation.

[0006] According to the invention, this task is accomplished by an electric drive system having the features of claim 1, and in particular the features in the feature portion of claim 1.

[0007] Advantageous designs of the present invention are the subject of the dependent claims.

[0008] An electric drive system is proposed, comprising at least two at least partially independent / separate drive systems, a first motor, and a second motor, wherein each drive system is capable of being coupled to either the first or the second motor, wherein each drive system is provided with at least one drive gear for coupling, and wherein a plurality of shifting elements are arranged for coupling at least one drive gear to a corresponding input shaft so as to selectively transmit its driving force to a corresponding output shaft. According to the invention, the shifting elements are configured to disengage the corresponding drive gear from the input shaft when the electric drive system operates in a partial load mode with a power demand below a specific threshold.

[0009] Similar to the hybrid drive systems described in the prior art, the pure electric drive system of the present invention utilizes two electric motors that drive the driven shaft of a combined transmission via a combined transmission comprising a main transmission and a range auxiliary transmission, the range auxiliary transmission comprising a planetary gear set. Subsequently, one or more drive axles of a vehicle (particularly commercial vehicles) are driven, for example, via this driven shaft. According to the invention, exactly two drive gears are coaxially arranged with the first input shaft of the main transmission, and exactly two drive gears are also coaxially arranged with the second input shaft of the main transmission. This generates a total of four discretely shiftable gears via the two motors, and corresponding virtual intermediate gears are generated as needed, without the overhead of additional drive gears, as is the case in hybrid drive systems.

[0010] By connecting the output shaft of the main gearbox to its input shaft using exactly two moving gears on each of the two input shafts and correspondingly exactly two fixed gears, such that one moving gear on each input shaft meshes with the first fixed gear on the output shaft and the other two moving gears on the corresponding input shaft mesh with the second fixed gear on the output shaft, a structure is created that enables power shifting in the respective states of the sub-gearbox. This can be achieved using a simple claw-type shifter, as specified in a particularly advantageous improvement of the electric drive system according to the invention. Therefore, unlike complex and easily worn friction shifters, shifting can now be performed in a simple, comfortable, and wear-optimized manner by switching the moving gears on the corresponding input shafts under load and synchronizing with the motor.

[0011] Another advantage is gained by positioning the two motors on two different input shafts, enabling a virtual intermediate gear that particularly improves starting performance. This is especially suitable for heavy-duty vehicles, making it a preferred application in the commercial vehicle sector, but other uses are not excluded.

[0012] Another advantage of using two motors is that during partial load operation (such as in long-haul commercial vehicle transport, which accounts for about 70% of the total mileage), one of the motors can be shut down (e.g., by disconnecting), thus affecting the overall lifespan and efficiency of these units.

[0013] Here, according to a highly advantageous improvement to this concept, a third fixed gear can be arranged coaxially with the output shaft of the main gearbox. This third fixed gear permanently meshes with a fourth fixed gear, which is then anti-rotationally connected to the first element of the planetary gear set. Such a connection with the planetary gear set, and therefore with the range auxiliary gearbox of the combined transmission, allows for a highly efficient and compact implementation of this structure.

[0014] In this context, "anti-rotation connection" refers to a connection between rotating and coaxially arranged elements that are linked together such that they rotate at the same angular velocity.

[0015] As noted above, the drive gears are connected to their respective input shafts in a switchable manner. According to a highly advantageous design of the invention, each input shaft region is provided with first and second shifting elements for the first and second drive gears or the third and fourth drive gears, respectively. Each first shifting element is configured to connect the first or third drive gear to its corresponding input shaft, and each second shifting element is configured to connect the second or fourth drive gear to its corresponding input shaft. Thus, a total of four shifting elements are provided in the input shaft region, one for each drive gear. They are designed to selectively connect or disconnect the drive gear from its input shaft, allowing the drive gear to rotate freely relative to the input shaft. This is sufficient to achieve a total of four gear positions, which are power-shiftable under the same conditions of the range sub-box, and can be selectively driven by any one or two of the motors.

[0016] According to another highly advantageous design based on this concept, the first and second shifters of the corresponding input shafts are combined into a dual shifter with a neutral position and an actuator. This use of dual shifters for the first and second shifters of the corresponding input shafts ultimately reduces the total number of required components to two dual shifters, one for each input shaft. Each dual shifter can be controlled by only one actuator, thus reducing the overhead of the actuation mechanism, resulting in an overall reduction in structural complexity and savings in space, installation space, and components.

[0017] Within the range gearbox, in a highly advantageous improvement to the electric drive system according to the invention, a braking shifter is provided for braking the third element of the planetary gear set. This allows the gear ratio of the range gearbox to be changed. Another highly advantageous design also specifies, alternatively or particularly supplementally, a locking shifter for locking the first and third elements of the planetary gear set.

[0018] According to a highly advantageous improved scheme that simultaneously incorporates a locking shifter and a braking shifter, these two shifters can also be combined again into a dual shifter with a single actuator, thereby correspondingly reducing overhead, as described above for each input shaft.

[0019] As described above, the rotors of the two motors are connected to or can be connected to the corresponding input shafts of the main gearbox. Here, according to a highly advantageous improvement of the electric drive system of the present invention, the rotor of the first motor is anti-rotationally connected to the first input shaft, and the rotor of the second motor is anti-rotationally connected to the second input shaft. This eliminates the need for additional shifting or clutch components between the rotors of the respective motors and the input shafts, since the input shafts are already switchably connected to the drive gear, and ultimately remain disengaged from the output shaft of the main gearbox of the combined transmission when the corresponding shifting component of the drive gear is in neutral. This eliminates the need for additional clutch components, thereby saving cost, installation space, and weight.

[0020] Within the range sub-gear, according to a highly advantageous improvement of the electric drive system of the present invention, the central gear of the planetary gear set can be configured as the first element, the planetary gear carrier as the second element, and the ring gear as the third element of the planetary gear set. Thus, in this configuration, the connection between the range sub-gear and the input shaft is achieved via the connection of the central gear, power output is achieved via the planetary gear carrier, and the ring gear, according to the aforementioned advantageous design, can be braked via a brake shifting element and / or directly anti-rotationally connected to the central gear via a locking shifting element.

[0021] Here, the first and second shifters on the corresponding input shafts can be configured as form-fitting shifters as described above, particularly as claw-type shifters. Their significant advantage lies in their largely wear-free operation. Based on the specific configuration of the combined transmission of the present invention, they can also achieve power shifting, where any potential power loss can be fully or at least partially compensated by the assistance of a corresponding additional motor, which can then undertake synchronous operation, thus enabling extremely smooth shifting despite the use of form-fitting shifters.

[0022] Each drive system is partially isolated and mechanically disengaged, allowing it to be deactivated. Furthermore, raising / adjusting the load point is also possible. This reduces losses (especially mechanical, electrical, and hydraulic losses).

[0023] Similar to the hybrid drive system described in the prior art, according to another aspect of the invention, a pure electric drive system utilizes two electric motors that drive the drive wheels of a vehicle (particularly a commercial vehicle) via a combined transmission comprising a main transmission and a range auxiliary gearbox. According to the invention, exactly two drive gears are coaxially arranged with the first input shaft of the main gearbox, and exactly two drive gears are also coaxially arranged with the second input shaft of the main gearbox. This generates a total of four discretely shiftable gears via the two motors, and corresponding virtual intermediate gears are generated as needed, without incurring the overhead of additional drive gears. The range auxiliary gearbox comprises two planetary gear sets, each arranged on the output side of the differential. The differential is connected to the output shaft of the main gearbox on the input side, which, according to a highly advantageous design, is via a cylindrical gear stage. Therefore, the range auxiliary gearbox is relocated to the axle and wheel area and is now directly located in that area in the form of two planetary gear sets corresponding to each drive wheel. The main gearbox of the combined transmission can therefore be implemented simply and efficiently, and only drives (preferably via the aforementioned cylindrical gear stage) the differential, while the range gearbox, in the form of planetary gear sets distributed to the respective drive wheels, is formed after the differential in the power transmission direction during vehicle driving.

[0024] Another advantage is gained by positioning the two motors on two different input shafts, enabling a virtual intermediate gear that significantly improves starting performance. This is particularly useful for heavy-duty vehicles, making it a preferred application in the commercial vehicle sector, though other uses are not excluded.

[0025] Another advantage of using two motors is that one of the motors can be shut down during partial load operation (such as in long-haul commercial vehicle transport, which accounts for about 70% of the total mileage), thus affecting the overall lifespan and efficiency of these units.

[0026] Within the range gearbox, according to a highly advantageous improvement of the electric drive system of the present invention, each planetary gear set is provided with two shifting elements. The first shifting element can lock the first and third elements, while the second shifting element can brake the third element of the corresponding planetary gear set. This allows for a corresponding change in the gear ratio of the range gearbox.

[0027] According to a highly advantageous improvement of the invention, the first shifting element as a locking shifting element and the second shifting element as a braking shifting element can be combined into a dual shifting element with one actuator, thereby also reducing overhead.

[0028] As noted above, the drive gears are connected to their respective input shafts in a switchable manner. According to a highly advantageous design of the invention, third and fourth shifters are provided in the region of each input shaft for either the first or second drive gears, or the third and fourth drive gears. Each third shifter is configured to connect the first or third drive gear to its corresponding input shaft, and each fourth shifter is configured to connect the second or fourth drive gear to its corresponding input shaft. Thus, a total of four shifters are provided in the region of the two input shafts, one for each drive gear. They are designed to selectively connect or disconnect the drive gear from its input shaft, allowing the drive gear to rotate freely relative to the input shaft. This is sufficient to achieve a total of four gear positions, which are power-shiftable under the same conditions of the range sub-box, and can be selectively driven by any one or two motors.

[0029] Here, the third and fourth shifters of the corresponding input shafts can be combined into a dual shifter with a neutral position and an actuator. This approach of using dual shifters for the third and fourth shifters of the corresponding input shafts ultimately reduces the total number of required components to two dual shifters, one for each input shaft. Each dual shifter can be controlled by only one actuator, thus reducing the overhead of the actuation mechanism, resulting in an overall reduction in structural complexity and savings in space, installation space, and components.

[0030] Another highly advantageous design of the electric drive system of the present invention can be specified herein, wherein the differential is configured as a differential with a switchable differential lock. This switchable differential lock constitutes a fifth shifter, which can be engaged independently of each gear as needed to establish a direct connection between the two axles and the wheels driven by the range gearbox via their respective planetary gears as transmission elements. Any slippage, wheel spin relative to another, or similar situations that may occur can then be prevented by operating this fifth shifter of the switchable differential lock in a manner known per se.

[0031] As described above, the rotors of the two motors are connected to or can be connected to the corresponding input shafts of the main gearbox. Here, according to a highly advantageous improvement of the electric drive system of the present invention, the rotor of the first motor is anti-rotationally connected to the first input shaft, and the rotor of the second motor is anti-rotationally connected to the second input shaft. This eliminates the need for additional shifting or clutch components between the rotors of the respective motors and the input shafts, since the input shafts are already switchably connected to the drive gear, and ultimately remain disengaged from the output shaft of the main gearbox of the combined transmission when the corresponding shifting component of the drive gear is in neutral. This eliminates the need for additional clutch components, thereby saving cost, installation space, and weight.

[0032] In this context, "anti-rotation connection" refers to a connection between rotating elements that links them together such that they rotate at the same angular velocity.

[0033] Within the range gearbox, according to a highly advantageous improvement of the electric drive system of the present invention, the central gear of each planetary gear set can be configured as a first element, the planetary gear carrier as a second element, and the ring gear as a third element of the planetary gear set. Thus, in this configuration, the connection between the range gearbox and the differential is achieved via the connection of the corresponding central gear to the axle, power output is achieved via the planetary gear carriers connected to the wheels respectively, and the ring gear, according to the aforementioned advantageous design, can be braked via a shift mechanism and / or directly anti-rotationally locked to the central gear.

[0034] Here, the third and fourth shifters on the corresponding input shafts can be configured as form-fit shifters as described above, particularly as claw-type shifters. Their significant advantage lies in their largely wear-free operation. Based on the special configuration of the combined transmission of the present invention, they can also achieve power shifting, where the power loss that may occur can be fully or at least partially compensated by the assistance of a corresponding additional motor, which can then undertake synchronous operation, so that extremely smooth shifting can be achieved despite the use of form-fit shifters.

[0035] The solution of this invention enables improved efficiency by mechanically disengaging the motor with or without drive system components (gearbox parts). This creates the possibility of improving efficiency within partial load ranges requiring less power. Furthermore, it allows for gear shifting without power interruption. Attached Figure Description

[0036] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0037] Figure 1 A schematic diagram of a gear train representing one possible structure of an electric drive system according to the present invention is shown.

[0038] Figure 2 A shift table is shown that describes the state of the shift mechanism in four gears.

[0039] Figure 3 A schematic diagram of a gear train representing one possible structure of an electric drive system according to the present invention is shown.

[0040] Figure 4 A shift table is shown that describes the state of the shift mechanism in four gears.

[0041] Corresponding components have the same reference numerals in all the accompanying drawings. Detailed Implementation

[0042] exist Figure 1 The view shows the electric drive system, generally indicated by 1. It has a first motor 2 and a second motor 3. The rotor of the first motor 2 is anti-rotationally connected to a first input shaft 4, and the rotor of the second motor 3 is anti-rotationally connected to a second input shaft 5. Input shafts 4 and 5 are components of the main gearbox 6 of the combined transmission 7. The output shaft 8 of the main gearbox 6 of the combined transmission 7 is connected to a range gearbox 9, which has a planetary gear set 10. Here, the output shaft 8 of the main gearbox 6 is connected to the center gear shaft 11 of the planetary gear set 10 of the range gearbox 9. The driven shaft 13 of the combined transmission 7 is driven via a planetary gear carrier 12, and this driven shaft meshes with a differential gear 15 via a gear 14, which is anti-rotationally connected to the differential housing of the differential transmission 16. Finally, the two exemplary drive wheels 17 of the electric drive axle of the vehicle (especially a commercial vehicle) are driven via the differential transmission 16. Here, the differential transmission 16 is common knowledge in the art and will not be described in detail. Hereinafter, it is exemplarily shown as a differential transmission 16 with a switchable differential lock.

[0043] Regarding the torque transmission from motors 2 and 3 to wheel 17, motors 2 and 3, main gearbox 6, range auxiliary gearbox 9, differential gear 15 and wheel 17 are arranged in the order described above.

[0044] A first moving gear 18 and a second moving gear 19 are arranged on the first input shaft 4 of the main housing 6. A third moving gear 20 and a fourth moving gear 21 are arranged on the second input shaft 5. Furthermore, shift members S1 and S2 or S1' and S2' are arranged on the corresponding input shafts 4 and 5 such that they can respectively anti-rotationally connect the moving gears 18, 19 or 20, 21, which are coaxially arranged with the corresponding input shafts 4 and 5. Preferably, shift members S1 / S2 and S1' / S2' are constructed as dual shift members with a neutral position, as shown here. Each dual shift member S1 / S2 is actuated by only one actuator.

[0045] The first moving gear 18 and the third moving gear 20 of the corresponding input shafts 4 and 5 mesh with the first fixed gear 22 on the output shaft 8. The second moving gear 19 and the fourth moving gear 21 mesh with the second fixed gear 23 on the output shaft 8. The input shafts 4 and 5 and the output shaft 8 are connected to each other only via these two fixed gears 22 and 23. Unlike the gear transmission schematic shown here, they are not usually arranged in a single plane. Therefore, a third fixed gear 24 can be provided between the two fixed gears 22 and 23, which meshes with the fourth fixed gear 25 on the central gear shaft 11 of the planetary gear set 10, thereby driving the central gear 26 of the planetary gear set 10 when the output shaft 8 of the main gearbox 6 of the combined transmission 7 is driven. The fourth fixed gear 25 is permanently anti-rotationally connected to the central gear 26 of the planetary gear set 10. In this way, the planetary gear set 10, as the range auxiliary gearbox 9, is driven by the output shaft 8 of the main gearbox 6 via the third gear 24 and the fourth gear 25. In the view of the gear train schematic diagram, the permanent meshing of the third fixed gear 24 and the fourth fixed gear 25 is indicated by the dashed line.

[0046] Planetary gears 27 on the planetary carrier 12 of the planetary gear set 10 mesh with the central gear 26 and the ring gear 28, which is the third element of the planetary gear set 10. Therefore, drive is performed via the central gear 26, which is the first element, and power output is performed via the planetary gears 27 or their planetary carrier 12, which is the second element of the planetary gear set. The ring gear 28 can be braked via a brake shifter S3 if necessary. In this case, the ring gear 28 is anti-rotationally connected to the housing of the combined transmission 7, for example, and therefore does not rotate. This produces a first gear ratio in the range auxiliary gearbox 9. The central gear 26, which is the first element of the planetary gear set 10, can also be connected or locked to the ring gear 28 via a locking shifter S4 (which can be combined with the brake shifter S3 to form a dual shifter). Thus, another gear ratio is generated between the central gear shaft 11, which acts as the input shaft, and the planetary carrier 12, which is connected to the driven shaft 13, in the range auxiliary gearbox 9.

[0047] exist Figure 2In the view, four individually shiftable gears are now shown in principle using a shift matrix. The first column shows the individual gears, the second column shows the position of the first shift member S1 or the first shift member S1' on the corresponding input shafts 4 and 5. The second column correspondingly shows the second shift member S2 or the second shift member S2', the third column shows the state of the third shift member (i.e., the braking shift member S3), and the fourth column shows the state of the locking shift member S4. In first gear, shift members S1 and / or S1' are engaged, thus connecting the first moving gear 18 or the third moving gear 20 to the corresponding input shaft 4 or 5, depending on which of the two motors 2 and 3 is driving, although both can also be driven together if needed. Simultaneously, the braking shift member S3 is closed, causing the gear ring 28 to be anti-rotationally braked, for example, on the housing of the combined transmission 7. Without changing the shifting state within the range sub-box 9, shifting from the first gear to the second gear can now be achieved by disengaging shift member S1 or S1' and engaging shift member S2 or S2' respectively, even under load. This shifting process can be synchronized by motors 2 and 3 as needed. Therefore, shifting between gears 1 and 2 or 3 and 4 can be performed very comfortably, and power shifting of the two associated gears 1 and 2 or 3 and 4 can be achieved in the corresponding state of the range sub-box 9. For this purpose, friction shift members are not required (a decisive advantage over existing technology), but shift members S1 and S2 or S1' and S2' can be configured as shape-fitting shift members, particularly as claw-type shift members. For the third and fourth gears, the shifting pattern is repeated again, except that, unlike gears 1 and 2, the range sub-box 9 is now shifted such that locking shift member S4 is activated and braking shift member S3 is disengaged accordingly.

[0048] By positioning the two motors 2 and 3 onto different input shafts 4 and 5, they can ultimately be positioned at different gears, thus achieving a virtual intermediate gear. This is achieved by driving the output shaft 8 in different ways with the two motors 2 and 3. The intermediate gear achievable in this way can particularly improve the starting performance of heavy vehicles (especially commercial vehicles). During normal operation (mostly partial load operation), operating one of the two motors 2 and 3 is sufficient. Therefore, the other motor 2 and 3, as well as the components of the main gearbox 6 of the combined transmission 7 connected to it, are not needed and can be disconnected, thereby reducing wear, improving efficiency, and extending structural life.

[0049] exist Figure 3 The view shows the electric drive system, generally indicated by 1. Here, Figure 1 The area enclosed by the dotted line exists in double form, as indicated by the label "2x". This area contains a first motor 2 and a second motor 3.

[0050] These motors are directly and anti-rotatably connected to the first input shaft 4 and the second input shaft 5 in the main housing of the combined transmission 7, designated 6. The output shaft 8 of the main housing 6 of the combined transmission 7 includes a cylindrical gear stage 10 (shown centrally), which has a fixed gear 14 that meshes with a gear 15 belonging to the cylindrical gear stage 10 in a differential 16. This differential drives two exemplary drive wheels 17 of the electrically driven axle of the vehicle (particularly a commercial vehicle). The differential 16 is exemplarily shown as a differential with a switchable differential lock.

[0051] A first moving gear 18 and a second moving gear 19 are arranged on the first input shaft 4 of the main housing 6. A third moving gear 20 and a fourth moving gear 21 are arranged on the same second input shaft 5. Furthermore, shift members S3 and S4 or S3' and S4' are arranged on the corresponding input shafts 4 and 5 such that they can anti-rotately connect the moving gears 18, 19 or 20, 21, which are coaxially arranged with the corresponding input shafts 4 and 5, to the corresponding input shafts 4 and 5, respectively. Preferably, shift members S3 / S4 and S3' / S4' are each constructed as a double shift member with a neutral position, as shown here. Each double shift member is actuated by only one actuator.

[0052] The first moving gear 18 and the third moving gear 20 of the corresponding input shafts 4 and 5 mesh with the first fixed gear 22 on the output shaft 8. The second moving gear 19 and the fourth moving gear 21 mesh with the second fixed gear 23 on the output shaft 8. The input shafts 4 and 5 and the output shaft 8 are connected to each other only via these two fixed gears 22 and 23. The aforementioned third fixed gear 14 is arranged between the two fixed gears 22 and 23, which meshes with the gear 15 of the differential 16, thereby driving the differential on its input side 11. When the output shaft 8 of the main gearbox 6 of the combined transmission 7 is driven, the two axles 13 with drive wheels 17 are thereby driven on the output side 12 of the differential 16.

[0053] Here, the range auxiliary gearbox 9 now consists of two planetary gear sets 24, 25, arranged between the output side 12 of the differential 16 (i.e., the axle 13) and the drive wheel 17. The planetary gear sets 24, 25 can, for example, be integrated into the wheel 17. Power output is directly directed to the wheel 17 via planetary carriers 29. The planetary gears 27 on the planetary carriers 29 of each planetary gear set 24, 25 mesh with the center gear 26 and ring gear 28 of their respective sets. Thus, drive is performed via the center gear 26 as a first element, and power output is performed via the planetary gears 27 or their planetary carriers 29 as second elements. If necessary, the ring gear 28, as a third element, is braked via a shift member S1 as a brake shifting element. The ring gear 28 is then anti-rotationally connected, for example, to the housing of the wheel suspension 30 or a similar object, and therefore does not rotate. This produces the first gear ratio of the range auxiliary gearbox 9. By means of the corresponding shift member S2, which acts as a locking shift member, the center gear 26, which is the first element of the corresponding planetary gear set 24, 25, can be connected or locked to the gear ring 28. As a result, another transmission ratio is generated between the axle 13, which acts as the input shaft in the corresponding planetary gear set 24, 25 of the range sub-box 9, and the planetary gear carrier 29, which is connected to the wheel as the output end.

[0054] exist Figure 4 In the view, four individually shiftable gears are now shown in principle using a shift matrix. The first column shows the gear numbers, and the second column shows the position of the dual shifter S1 / S2, consisting of the first shifter and the second shifters S1 and S2, in the planetary gear set 24 shown on the left. Here, the second column shows the three shifting positions of the dual shifter S1 / S2: the left shifting position (which represents the braking shifting position in the planetary gear set 24), the middle neutral position (as shown in the image), and the middle neutral position. Figure 3 The view shown is shown above, as is the right-hand position (which represents the lock-up shift position). The third column then selects the same structure. Now, the shift positions show the corresponding shift positions of the dual shifters S1 / S2 of another planetary gear set 25, which consists of the first and second shifters S1, S2. Since the structure here is basically mirror-symmetrical to the differential 16, the left column here represents the lock-up shift position, the right column represents the brake shift position, and according to the middle column, the structure is in the neutral position shown here, which is not used in practice.

[0055] The other two columns, labeled S3 / S3' and S4 / S4' respectively, now relate to the third and fourth shifters arranged on the corresponding input shafts 4 and 5. Here, three positions can again be seen: the middle position is neutral; the left position is where the first or third moving gear 18 or 20 of the corresponding input shaft 4 or 5 is connected to its anti-rotational component; and correspondingly, the right position is where the second or fourth moving gear 19 or 21 is connected to its corresponding input shaft 4 or 5.

[0056] Therefore, in first gear, in the example of the shift matrix shown here, the two motors 2, 3 are driven via second and fourth drive gears 19, 21, which drive the output shaft 8 of the combined transmission 6 via fixed gears 22, 23. Subsequently, the differential 16 is driven via a cylindrical gear stage 10 with fixed gears 14 and 15. Subsequently, the drive wheel 17 is driven via the axle 13 between the output side 12 of the differential 16 and the planetary gear sets 24, 25 of the range auxiliary gearbox 9. In both cases, the dual shifters S1 / S2 of the corresponding planetary gear sets 24, 25 are both in the braked position of the ring gear 28. When shifting to second gear, the shift occurs only on the corresponding input shafts 4, 5, from the second or fourth drive gear 19, 21 to the first or third drive gear 18, 20. When shifting from second to third gear, the gears then switch from braking shifting of the two planetary gear sets 24 and 25 to their locking shifting, and then switch back to the second and fourth driving gears 19 and 21 in the combined transmission 6, before switching back to the first and third driving gears 18 and 20 in the fourth gear.

[0057] For both shifting processes from first to second gear or from third to fourth gear, the shifting positions within the planetary gear sets 24 and 25 of the range sub-box 9 remain unchanged. Therefore, shifting from first to second gear can now be achieved by disengaging shift member S3 or S3' and engaging shift member S4 or S4' respectively, even under load, where the shifting process can be synchronized by motors 2 and 3 as needed. This allows for very comfortable shifting between gears 1 and 2 or 3 and 4, and enables power shifting of the two associated gears 1 and 2 or 3 and 4 within the corresponding positions of the range sub-box 9. For this purpose, friction shifting members are not required (a decisive advantage over existing technology), and shift members S3 and S4 or S3' and S4' can be configured as shape-fitting shifting members, particularly as claw-type shifting members.

[0058] By positioning the two motors 2 and 3 onto different input shafts 4 and 5, respectively, they can ultimately be positioned at different gears, thus achieving a virtual intermediate gear. This is achieved by driving the output shaft 8 in different ways with the two motors 2 and 3. The intermediate gear achievable in this way can particularly improve the starting performance of heavy-duty vehicles (especially commercial vehicles). In normal operation (mostly partial load operation), operating one of the two motors 2 and 3 is sufficient, eliminating the need for the other motor 2 and 3 and the components of the main gearbox 6 of the connected combined transmission 7. This reduces wear, increases efficiency, and extends structural life.

[0059] List of reference numerals

[0060] 1 Electric drive system

[0061] 2 motors

[0062] 3 Second motor

[0063] 4 input axes

[0064] 5 input axes

[0065] 6 main boxes

[0066] 7-speed combination transmission

[0067] 8 output shafts

[0068] 9 range auxiliary boxes

[0069] 10 planetary gear sets, cylindrical gear stages

[0070] 11 center gear shaft

[0071] 12 Planetary Gear Carrier

[0072] 13 Driven axle, axle

[0073] 14 gears, fixed gears

[0074] 15 differential gears, gears

[0075] 16. Differential gear, differential transmission device

[0076] 17 wheels, drive wheels

[0077] 18 moving gears

[0078] 19 moving gears

[0079] 20 moving gears

[0080] 21 moving gears

[0081] 22 fixed gears

[0082] 23 fixed gears

[0083] 24 fixed gears, planetary gear set

[0084] 25 fixed gears, planetary gear set

[0085] 26 center gears

[0086] 27. Planetary gears, planetary wheels

[0087] 28-tooth ring

[0088] 29 Planetary Gear Carrier

[0089] 30-wheel suspension

[0090] S1, S1', S2, S2' shifters

[0091] S1 / S2, S1' / S2' Dual Shifter

[0092] S3 and S3' shifters, brake shifters

[0093] S4 and S4' shifters, lock-up shifters

Claims

1. An electric drive system (1) having at least two drive systems at least partially separated from each other, a first motor (2) and a second motor (3), wherein, The drive system can be connected to the first or second motor (2, 3) respectively, wherein at least one moving gear (18 to 21) is arranged for connection, and a plurality of shift members (S1, S1'; S2, S2') are arranged for connecting at least one of the moving gears (18 to 21) to the corresponding input shaft (4, 5) so as to selectively transmit its driving force to the corresponding output shaft (8). The characteristic feature is that the shifting components (S1, S1'; S2, S2') are configured to disengage the corresponding moving gears (18 to 21) from the input shafts (4, 5) when the electric drive system (1) is operating in a partial load mode with a power demand lower than a certain threshold.

2. The electric drive system (1) according to claim 1, characterized in that, The transmission includes a differential transmission (16), drive wheels (17), and a combined transmission (7). The combined transmission includes a main gearbox (6) and a range gearbox (9), wherein the range gearbox (9) has a planetary gear set (10). The first input shaft (4) of the main gearbox (6) is connected to or can be connected to the first motor (2) in such a way that torque can be introduced from the first motor (2) through the first input shaft (4) into the combined transmission (7). The second input shaft (5) of the main gearbox (6) is connected to or can be connected to the second motor (3) in such a way that torque can be introduced from the second motor (3) through the second input shaft (5) into the combined transmission (7). The output shaft (8) of the main gearbox (6) is connected to the first element (26) of the planetary gear set (10) in a manner that permanently transmits torque, and the second element (12) of the planetary gear set is connected to the driven shaft (13) of the combined transmission (7) in a manner that permanently transmits torque. Regarding the torque transmission from the motors (2, 3) to the wheel (17), the first motor (2), the main gearbox (6), the range auxiliary gearbox (9), the differential gear (15), and the wheel (17) are arranged in the aforementioned order. Two moving gears (18, 19) are arranged coaxially with the first input shaft (4), namely the first moving gear (18) and the second moving gear (19). Two other moving gears (20, 21) are arranged coaxially with the second input shaft (5), namely the third moving gear (20) and the fourth moving gear (21). The two input shafts (4, 5) are connected to or can be connected to the output shaft (8) through two fixed gears (22, 23) arranged coaxially with the output shaft (8). The first fixed gear (22) of the fixed gears (22, 23) is permanently meshed with the first and third moving gears (18, 20), and the second fixed gear (23) of the fixed gears (22, 23) is permanently meshed with the second moving gear (19) and the fourth moving gear (21).

3. The electric drive system (1) according to claim 2, characterized in that, A third fixed gear (24) is arranged coaxially with the output shaft (8), and the third fixed gear is permanently meshed with a fourth fixed gear (25), which is anti-rotationally connected to the first element (26) of the planetary gear set (10).

4. The electric drive system (1) according to claim 2 or 3, characterized in that, Each of the input shafts (4, 5) is provided with a first and second shift member (S1, S1'; S2, S2') for the first and second moving gears (18, 19) or the third and fourth moving gears (20, 21), wherein each first shift member (S1, S1') is configured to connect the first moving gear (18) or the third moving gear (20) to its corresponding input shaft (4, 5), and wherein each second shift member (S2, S2') is configured to connect the second moving gear (19) or the fourth moving gear (21) to its corresponding input shaft (4, 5).

5. The electric drive system (1) according to claim 4, characterized in that, The first and second shift members (S1, S1'; S2, S2') of each input shaft (4, 5) are combined into a dual shift member having a neutral position and an actuator.

6. The electric drive system (1) according to any one of claims 2 to 5, characterized in that, The system includes a braking shifter (S3) for braking the third element (28) of the planetary gear set (10), and / or a locking shifter (S4) for locking the first and third elements (26, 28) of the planetary gear set (10).

7. The electric drive system (1) according to claim 6, characterized in that, The braking shift member (S3) and the locking shift member (S4) are combined into a dual shift member having one actuator.

8. The electric drive system (1) according to any one of claims 1 to 7, characterized in that, The rotor of the first motor (2) is anti-rotationally connected to the first input shaft (4), and the rotor of the second motor (3) is anti-rotationally connected to the second input shaft (5).

9. The electric drive system (1) according to any one of claims 2 to 8, characterized in that, In the planetary gear set (10), the center gear (26) is constructed as the first element, the planetary gear carrier (12) is constructed as the second element, and the gear ring (28) is constructed as the third element.

10. The electric drive system (1) according to any one of claims 1 to 9, characterized in that, The shifters (S1, S1'; S2, S2') assigned to the corresponding input shafts (4, 5) are respectively constructed as shape-fitting shifters, and in particular as claw shifters.

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