Electric axle

Abstract

Electric axle system that includes: an electric machine; and a multi-speed gearbox rotatably connected to the electric machine, rotatably connected to two output shafts and includes: a differential rotatably coupled to a mode planetary gear set and arranged coaxially thereto; and a mode coupling configured to selectively switch the mode planetary gear set to the following: a first mode in which the mode coupling engages a carrier or ring gear included in the mode planetary gear set; and a second mode in which the mode coupling rotatably couples the carrier to the ring gear.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority to U.S. Provisional Application No. 63 / 515,673, entitled "ELECTRIC AXLE," filed on July 26, 2023. The entire contents of the above-referenced application are hereby incorporated by reference for all purposes. TECHNICAL FIELD

[0002] This description generally refers to an electric axle with two concentric planetary gear sets. BACKGROUND AND SUMMARY

[0003] Electric axles are used in a wide variety of vehicle platforms to meet the electrification needs of different vehicle sectors. These electric axles include traction motors and transmissions, which can be mounted in different configurations depending on the spatial constraints and intended use of the vehicle platform. Electric axles can enable simpler and more efficient integration of the vehicle platform than electric drives, where the traction motor, transmission, and drive axles are designed as separate units.

[0004] At least some electric axles fail to meet the end-application targets for space efficiency, shifting functionality, and power density. For example, some multi-speed transmissions utilize numerous parallel shafts and gears, which pose a challenge during installation. Furthermore, in previous multi-speed transmissions, all gears mesh with each other, but in certain modes, torque is transmitted only through a portion of the gears, while other gears remain unloaded. Therefore, the unloaded gears cause unavoidable bearing, meshing, and ventilation losses. Inventors therefore recognized the desire to reduce installation space and increase the power density of electric axles.

[0005] The problems described above can be solved by an electric axle system. In one example, the electric axle system includes an electric machine and a multi-speed transmission rotatably coupled to the electric machine and rotatably coupled to two output shafts. The multi-speed transmission includes a mode planetary gear set rotatably disposed coaxially with a differential. The multi-speed transmission also includes a mode clutch configured to selectively shift the multi-speed transmission between a first mode and a second mode. In one example, the mode planetary gear set in the electric axle system is a compound planetary gear set with intermeshing planets. In this way, the mode planetary gear set effectively achieves two gear ratio modes in a space-saving package and expands the speed-changing capabilities of the system.

[0006] In one example, the differential is a compound planetary gear set with meshing planets. This allows for a space-saving electric axle with a desired power density. This means that the use of the compound planetary gear set with meshing planets and the mode planetary gear set in this configuration makes it possible to eliminate the need for additional shafts (e.g., countershafts with idler gears) for the electric axle if desired, while still achieving a desired number of transmission modes and mode ratios. This increases customer appeal.

[0007] In one example, the electric axle system further includes a differential lock clutch configured to selectively rotatably couple a ring gear in the differential to a carrier in the differential to lock the rotation of the two output shafts. In another example, the electric axle additionally includes an axle disconnect clutch configured to selectively disconnect the mode planetary gear set from the differential. In this way, the functionality of the electric axle is expanded by the possibility of differential lock and axle decoupling, further increasing its appeal to customers.

[0008] It should be understood that the above summary is intended to introduce, in simplified form, a selection of concepts that are further explained in the detailed description. It is not intended to identify the most important or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or elsewhere in this disclosure. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1A-1B show an example of an electric axle with a differential compound planetary gear set with intermeshing planets, a mode planetary gear set, and a mode clutch. Fig. Figure 2 shows an example of an electric axle system with a differential compound planetary gear set with intermeshing planets, a mode planetary gear set, a mode clutch, a differential lock clutch and an axle disconnect clutch. Fig. 3A-3D show various example architectures for electric machines and input gear transmissions for the electric axle system from Fig. 2. Fig. 4-7 show various examples of a transmission for an electric axle with a differential compound planetary gear set with intermeshing planets and a mode planetary gear set rotatably coupled to another planetary gear set, in various configurations. Fig. Figure 8 shows another example of an electric axle with a mode planetary gear set and a limited-slip differential. Fig. Figure 9 shows another example of an electric transmission with a multi-speed mode planetary gear set and a differential compound planetary gear set with intermeshing planets. Fig. Figure 10 shows another example of an electric axle with a mode planetary gear set and a double sun gear differential. Fig. 11 shows another example of an electric axle with a mode planetary gear set and an open differential. DETAILED DESCRIPTION

[0009] This article describes a multi-speed electric differential axle with mode selection functionality that achieves greater compactness and power density. Previous multi-speed electric axles utilize multiple parallel shafts, which presents installation challenges. For example, some multi-speed electric axles utilize at least two shafts for gear shifting. In these electric axles, all gears mesh with each other, but in certain modes, torque is only transmitted through a portion of the gears, while other gears remain unloaded. Therefore, the unloaded gears cause unavoidable bearing, meshing, and ventilation losses. Furthermore, ring gear differentials are comparatively wide and can cause axial installation issues in certain vehicles, limiting the differential's applicability. Certain planetary differentials, such as the 2-speed differential, require a larger diameter and a larger diameter.Compound planetary differentials with two output sun gears or two output ring gears, two concentric simple planetary gear sets side by side, and two nested concentric planetary gear sets may also pose problems with the axial length and / or overall diameter of the drive axle. However, the above-mentioned types of planetary gear sets can be used in any of the electric axles described here.

[0010] As described herein, a simple planetary gear set is a planetary gear set with only a ring gear, a sun gear, a carrier gear, and a plurality of planet gears that lie in the same plane as the ring gear and sun gear and rotate on the carrier gear. Each planet gear meshes with both the sun gear and the ring gear. Further, a compound planetary gear set with intermeshing planets as described herein is a planetary gear set with a ring gear, a sun gear, and a plurality of sets of planet gears that mesh in the plane of the ring gear and sun gear and are circumferentially aligned in the same plane as the ring gear and sun gear. The planetary sets include an inner and an outer planet gear. The inner planet gear meshes with the sun gear and an outer planet gear. The outer planet gear meshes with an inner planet gear and the ring gear.

[0011] To achieve the desired space efficiency and power density, one example of the electric axle includes a transmission with a multi-speed mode-selecting planetary gear set and a compact planetary differential in a coaxial housing. Specifically, the multi-speed gear set in the transmission includes a mode-selecting planetary gear set with a mode clutch for switching between gear modes.

[0012] In one example, the electric axle includes a differential planetary gear set and a mode planetary gear set concentric with the output axis of the electric axle. Additionally, the differential in the electric axle may be formed from a compound planetary gear set with intermeshing planetary gears. By using mode and differential planetary gear sets, multiple gear shifting shafts can be eliminated from the system if desired. As a result, space efficiency is increased, the width of the differential is reduced, and the overall axial length of the electric axle can be reduced, if desired, allowing for a more compact and powerful electric axle architecture. Unlike previous multi-speed electric axles with idler gears on countershafts, the multi-speed electric axle allows all gears to transmit torque.Specifically, this means that there must be no idle gears in the system, which cause bearing, mesh, and ventilation losses when the transmission is operating in a neighboring speed range. This increases the transmission's efficiency.

[0013] When the multi-speed electric differential axle (e.g., two-speed) is in a lower mode, there is a relative speed between the elements of the planetary gear set. In the higher mode, the planetary gear set is locked and rotates as a single unit. The differential planetary gear set can also rotate as a single unit, differentiating only when the vehicle is turning. In practice, the transmission may be operated in the higher mode for a greater portion of its operating life than in the lower mode (e.g., most of the time). In the higher mode, the planetary gear sets rotate as a single unit.Because the components of the differential planetary gear set and the mode planetary gear set do not rotate relative to each other, meshing noise is reduced, gear wear is reduced, component lifespan is increased, friction losses are reduced, and ventilation losses are reduced, thus increasing the overall efficiency of the axle. With increased lifespan and a larger number of planetary gear pairs, it is possible to reduce the width of the differential planetary gear set and the mode planetary gear set, thereby reducing the axial length of the electric axle, if desired.Additionally, in certain end-use scenarios where the electric axle operates in the higher mode for longer than the lower modes and there is no relative velocity between the meshing planetary pairs, it is possible to use spur gears in the planetary gear sets, further reducing the cost and complexity of the electric axle and simplifying the manufacturing of the differential planetary gear set and mode planetary gear set components.

[0014] The multi-speed electric differential axle layouts described here allow for axle separation and differential lock to be easily and effectively incorporated into the axle, if desired. Consequently, the electric axles are capable of achieving additional features that are difficult to achieve with other axle architectures, such as a parallel-axis differential. Furthermore, it is understood that the electric axles described here can be designed with the electric motor concentric with the output axle, coaxial with the output axle, parallel to the output axle, at a 90° angle to the output axle, or at other suitable angles to the output axle.

[0015] Fig. 1A shows an example of an electric axle 100 with a transmission 102 including a mode planetary gear set 104. The electric axle 100, in the example shown, also includes a differential compound planetary gear set with intermeshing planets 105. The mode planetary gear set 104 and the differential compound planetary gear set with intermeshing planets 105 are discussed in more detail herein.

[0016] The electric axle 100 is included in an electric vehicle (EV) 103 in the illustrated example. It should be understood that the other electric axles described herein may also be included in a similar EV. The EV 103 may be a pure electric vehicle (e.g., a battery electric vehicle (BEV)) in one example or a hybrid vehicle in another example. Thus, in some examples, vehicles utilizing the electric axles described herein may also have an internal combustion engine (e.g., a gasoline engine, a compression-ignition engine, combinations thereof, and the like). Thus, the electric axles described herein may be used in cars, trucks, off-highway vehicles, commercial vehicles, light vehicles, off-highway vehicles, mining vehicles, rail vehicles, manufacturing equipment, industrial equipment, and the like.

[0017] Furthermore, the mode planetary gear set 104 in the illustrated example is a compound planetary gear set with intermeshing planets. For explanation: In the illustrated example, the mode planetary gear set 104 includes two sets of planet gears 110 and 116, wherein the planet gears mesh with each other. Furthermore, the planet gears of the planetary gear set 110 mesh with a sun gear 106, and the planet gears of the planetary gear set 116 mesh with a ring gear 114. In other examples, however, the mode planetary gear set may also have a larger number of planetary gear sets and / or a different gear architecture. The sets of planet gears 110 and 116 are rotatably mounted on a carrier 108. Furthermore, an input shaft 107 is connected to the sun gear 106 in the example shown. It is understood that the input shaft 107 may be coupled to a traction motor via shafts, gears, chains, belts, combinations thereof, and the like.Various example arrangements for the engine and the associated components that connect the engine to the transmission are described here with reference to . Fig. 2-3D is further explained.

[0018] The mode planetary gear set 104 can be specifically configured to switch between two modes. However, electric axles with a larger number of gears, such as a three-speed electric axle, a four-speed electric axle, etc., are also conceivable. To enable the multi-speed functionality of the transmission, a mode clutch 120 is provided in the transmission. The mode clutch 120 is configured to anchor the carrier 108 in a first mode and to rotatably couple the carrier 108 and the ring gear 114 in a second mode. In the example shown, the mode clutch 120 is in the first mode. However, the mode clutch 120 can be switched to different modes depending on the operating conditions of the electric axle and / or the vehicle. In addition, the first mode has a higher gear ratio than the second mode.The specific gear ratios assigned to the modes can be selected based on factors such as the type and performance characteristics of the electric motor, vehicle weight, vehicle performance objectives, etc.

[0019] The mode clutch 120 may be a dog clutch, a synchronizer, a friction clutch (e.g., a wet friction clutch), a radial clutch, a face clutch, a cam clutch, a magnetic clutch, combinations thereof, and the like. The other clutches described herein may also be any of the above-mentioned types or combinations of clutch types. Furthermore, the mode clutch 120, as well as the other clutches described herein, may be actuated via electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, drum cam actuators, combinations thereof, and the like. Shift forks, e.g., translational or rotary shift forks, may be specifically used to actuate at least a portion of the clutches described herein.

[0020] The differential compound planetary gear set with intermeshing planets 105 is rotatably coupled to the single planetary gear set 104. For illustration, the ring gear 114 in the mode planetary gear set 104 is coupled via a shaft 124 and / or other suitable mechanical components to a ring gear 122 in the differential compound planetary gear set with intermeshing planets 105. By attaching the differential compound planetary gear set with intermeshing planets and the mode planetary gear set in this manner, the transmission can be arranged compactly and a desired gear ratio can be achieved.

[0021] The differential compound planetary gear set with intermeshing planets 105 further includes a set of planet gears 126, a set of planet gears 128, and a sun gear 130. Also included in the differential compound planetary gear set with intermeshing planets 105 is a carrier member 132 to which the set of planet gears 126 and the set of planet gears 128 are rotatably mounted. In the illustrated example, an output shaft 134 (e.g., an axle shaft such as a half shaft) is coupled to the carrier member 132, and another output shaft 136 is coupled to the sun gear 130. The output shafts 134 and 136 are, in turn, rotatably coupled to drive gears 138 in the illustrated example. However, in other examples, the output shafts 134 and 136 may be coupled to wheel-side gear reductions and / or other suitable mechanical components.

[0022] In the electrical axis 100 from Fig. 1A, the carrier 132 and sun gear 130 of the differential compound planetary gear set with intermeshing planets 105 act as the outputs of the differential, and the sun gear 106 of the mode gear set acts as the input of the electric axle. However, differentials with different output configurations may be used in the electric axle, as described herein with reference to Fig. 8, Fig. 10 and Fig. 11 will be explained in more detail.

[0023] In the example shown, the mode planetary gear set 104 and the differential compound planetary gear set with intermeshing planets 105 are concentric with the output rotational axis of the electric axle. This increases the compactness of the axle compared to electric drives with a non-concentric arrangement. For reference, a rotational axis 180 of the differential compound planetary gear set with intermeshing planets 105 is shown in Fig. 1A. It is understood that the rotational axis of the input of the mode planetary gear set 104 and the rotational axes of the output shafts 134 and 136 are arranged coaxially with the rotational axis 180.

[0024] The use of the mode planetary gear set 104 and the differential compound planetary gear set with intermeshing planets 105 can allow for the elimination of additional shafts and shift gears from the transmission (if desired), reducing the installation size, narrowing the transmission width, and reducing the overall axial length, enabling a more compact and power-dense electric axle design if desired. This increases the efficiency of the transmission.

[0025] As previously mentioned, when the mode planetary gear set 104 operates in the lower mode, a relative velocity exists between the elements of the multi-stage mode planetary gear set. In the higher mode, the mode planetary gear set is locked and rotates as a single unit. The differential can also rotate as a single unit and only differentiates when the vehicle is turning. The majority of the electric axle's service life can occur in the highest mode for certain end applications, reducing component wear and cooling losses and increasing the efficiency of the electric axle.

[0026] A coordinate axis system is in Fig. 1A, as well as in Fig. 2-11 for reference and, if necessary, for orientation of the views. In one example, the z-axis may be a vertical axis (e.g., parallel to a gravitational axis), the x-axis may be a lateral axis (e.g., a horizontal axis), and the y-axis may be a longitudinal axis. In other examples, the axes may have other orientations. Furthermore, the rotational axis 180 of the sun gear 130 is provided as a reference in Fig. 1A, as already mentioned. The mode planetary gear set 104 and the differential compound planetary gear set with intermeshing planets 105 are arranged coaxially in the example shown. The other electric transmissions described here also have the coaxial arrangement between the mode planetary gear set and the differential. In this way, the electric transmission can achieve the desired space efficiency.

[0027] As in Fig. 1A, the EV 103 may also include a control system 150 having a controller 152. The controller 152 may include a microcomputer with components such as a processor 154 (e.g., a microprocessor unit), input / output ports, an electronic storage medium 156 for executable programs and calibration values ​​(e.g., a read-only memory chip, read-only memory, diagnostic memory, a data bus, and the like). The storage medium may be programmed with computer-readable data representing instructions executable by a processor to perform the methods, control techniques, etc. described herein, as well as other variations that are expected but not explicitly listed. Thus, instructions may be stored in the electronic storage medium 156 that, when executed by the processor 154, cause the controller 152 to perform the various method steps described herein.

[0028] The controller 152 may receive various signals from sensors 158 coupled to different areas of the EV 103, and in particular, the electric axle 100. The sensors 158 may include, for example, one or more engine speed sensors (see below), shaft / gear speed sensors, thermocouples, pressure sensors, a pedal position sensor for detecting the depression of a driver-operated pedal (e.g., an accelerator pedal and / or a brake pedal), speed sensors at the vehicle wheels, and the like. An input device 160 (e.g., accelerator pedal, brake pedal, gear selector, combinations thereof, and the like) may also provide input signals indicating the driver's intent for vehicle control.

[0029] After receiving the signals from the various sensors 158 from Fig. 1A, the controller 152 processes the received signals and deploys various vehicle component actuators 162 to adjust the components based on the received signals and the instructions stored in the memory of the controller 152. For example, the controller 152 may receive an accelerator pedal signal indicating the driver's request for an adjustment in vehicle acceleration. In response, the controller 152 may command the operation of inverters electrically coupled to an electric machine that supplies power to the mode planetary gear set to increase the power delivered from the engine to the transmission 102. The other controllable components in the vehicle may function similarly, e.g., with respect to sensor signals, control commands, and actuator adjustment. Furthermore, the control system 150 may be employed in any of the electric axle systems and transmissions described herein.

[0030] The controller 152 may include instructions that, when executed, cause the mode clutch 120 to switch between the first mode and the second mode, also referred to as lower mode and higher mode, depending on the operating conditions of the vehicle and axle. For example, the electric axle 100 may operate in the first mode when the vehicle is traveling at lower speeds. When the vehicle speed exceeds a first threshold, the mode clutch may switch to the second mode. This switching sequence may also be performed in reverse order through the modes. The control system 150 described above may be employed in any of the electric axles and transmissions described herein.

[0031] Fig. 1B shows a lever diagram 190 of the architecture of the electric axis 100 of Fig. 1A. The two functions of the mode clutch 120 from Fig. 1A, corresponding to the first mode and the second mode, are indicated via devices 172 and 174, respectively. However, it should be understood that the mode clutch 120 may be configured to perform mode switching as a clutch unit. As previously mentioned, in the first mode, the carrier member 108 is anchored, and in the second mode, the carrier member 108 and the ring gear member 114 are rotatably coupled. The input of the mode planetary gear set 104 is indicated by arrow 176, and the outputs of the differential compound planetary gear set with intermeshing planets 105 are indicated by arrows 178 and 179. The direction of rotation of the input of the transmission is the same as the directions of rotation of the outputs of the transmission in the example shown. However, other transmission designs are also possible.

[0032] Fig. 2 shows an electric axle 200 with a transmission 202 including a mode planetary gear set 204 and a differential compound planetary gear set with intermeshing planets 206. The architecture of the mode planetary gear set 204 and the differential compound planetary gear set 206 with intermeshing planets is similar to the mode planetary gear set 104 and the differential compound planetary gear set with intermeshing planets 105 of Fig. 1A. The gearbox 202 from Fig. 2 again includes a mode clutch 208 that allows the transmission to achieve multi-speed functionality, similar to the transmission 102 of Fig. 1A.

[0033] Fig. 2 shows, in particular, an electric machine 210 in the electric axle 200. As described here, the electric machines connected to the electric axles may be traction motors (e.g., motor generators). The electric machine 210 of Fig. 2 is specifically arranged concentrically with the differential compound planetary gear set with intermeshing planets 206 and the mode planetary gear set 204. For clarity, an inner diameter 207 of a rotor 209 of the electric machine 210 is shown circumferentially surrounding at least a portion of the transmission and, in particular, the mode planetary gear set 204. However, as explained in more detail herein, the electric machine may have a variety of suitable positions and orientations. In the example shown, at least a portion of the compound planetary gear sets with intermeshing planets is arranged within an internal opening of the electric machine.

[0034] Fig. 2 also shows a differential lock clutch 212 and an axle disconnect clutch 214. The differential lock clutch 212 is configured to rotatably couple the carrier 216 and a ring gear 218 within the compound planetary gear set with meshing planets 206. In this manner, the differential can be selectively locked to increase axle performance, particularly in low-traction operating environments (e.g., in all-wheel drive applications). The differential lock clutch 212 enables the output shafts 242 and 243 (e.g., axle shafts) of the compound planetary gear set with meshing planets 206 to be selectively locked from each other. In addition, the axle disconnect clutch 214 is configured to selectively decouple the ring gear 218 in the differential compound planetary gear set with intermeshing planets 206 and a ring gear 220 in the mode planetary gear set 204.The axle disconnect clutch 214 allows the differential lock clutch 212 and the axle disconnect clutch 214 to be selectively decoupled from the mode planetary gear set 204. Either or both of the differential lock clutch 212 and the axle disconnect clutch 214 can be integrated into any of the transmissions described herein. The axle disconnect clutch 214 allows the vehicle's driveline efficiency to be increased when towing, transporting a series of stacked vehicles, or when using an electric axle in a tandem axle configuration as a tag axle.

[0035] Bearings 222 may be coupled to an input shaft 223 of the transmission 202. The input shaft 223 connects the mode planetary gear set 204 to the electric machine 210. As described herein, a bearing may include an inner race, rolling elements (e.g., cylindrical rollers, balls, tapered cylindrical rollers, needle rollers, bushings, etc.), and an outer race. In the illustrated example, a bearing 224 is coupled to a sun gear member 226 in the mode planetary gear set 204. Additionally, a bearing 228 is coupled to a carrier member 230 in the mode planetary gear set. In the illustrated example, another bearing 232 is coupled to the carrier member 230 and the ring gear member 220. Additionally, in the example shown, bearings 234 and 246 are coupled to shafts 236 and 248, respectively, and / or other suitable mechanical structures connected to ring gears 218 and 220.A bearing 238 may be coupled to the ring gear 218 and the carrier 216, a bearing 240 may be coupled to the output shaft 243 and the carrier 216, and a bearing 244 may be coupled to the carrier 216. The bearings in the transmission may also be arranged differently in alternative embodiments.

[0036] Fig. 3A-3D show various arrangements of electric machines and gear drives for axle shafts of the mode planetary gear set 204 in various electric axle architectures. The architecture of the mode planetary gear set 204, the differential compound planetary gear set with intermeshing planets 206, the mode clutch 208, the differential lock clutch 212, and the axle disconnect clutch 214 in the transmission 202 is similar to the component architecture and layout of Fig. 2. For the sake of brevity, a redundant description of the overlapping components is therefore omitted.

[0037] Fig. In particular, Figure 3A shows an electric axle 349 with an electric machine 350 positioned concentrically with the output shaft 243 and disposed on an outer axial side 352 of the mode planetary gear set 204. A portion of one of the output shafts extends through an opening in the electric machine 350 in the illustrated example. This increases the space efficiency of the electric axle. Fig. 3A further shows bearings 353 coupled to the electric machine 350. The electric axis includes additional bearings with a similar arrangement as in Fig. 2. For example, rotating shafts and gears are generally connected to bearings. The other electrical axes in Fig. 3B-3D also include a similar bearing arrangement in the mode planetary gear set 204, the differential compound planetary gear set with intermeshing planets 206, the axle disconnect clutch 214, and the differential lock clutch 212. However, other bearing arrangements are possible, and at least one of the differential lock clutch 212 and the axle disconnect clutch 214 may be omitted from any of the electric axle architectures shown in Fig. 2-3D. As previously mentioned, the axle disconnect clutch 214 and the differential lock clutch 212 may be dog clutches, synchronizers, friction clutches (e.g., wet friction clutches), radial clutches, face clutches, cam clutches, magnetic clutches, combinations thereof, and the like. Furthermore, the axle disconnect clutch 214 and the differential lock clutch 212 may be actuated via electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, drum cam actuators, combinations thereof, and the like. Shift forks, e.g., translatory or rotary shift forks, may be specifically used to actuate at least a portion of the clutches described herein, as previously mentioned.

[0038] Fig. 3B shows an electric axle 359 with two electric machines 360 and 362, each arranged parallel to one of the output shafts 242 and 243 and mechanically connected to the input of the transmission 202 via gear trains 363 and 367. A gear 365 meshes with the gears in each of the gear trains 363 and 367 and establishes a mechanical connection between a shaft 364 rotatably coupled to the input of the mode planetary gear set. Specifically, the gear train 363 includes a shaft 361 with a gear 371 mounted thereon. The gear 371 meshes with a gear 373 mounted on a shaft 375. Another gear 377 is mounted on shaft 375 and meshes with gear 365. In this way, two gear pairs rotatably couple the electric motor 360 and the mode planetary gear set. In the example shown, the gear transmission 367 has a similar structure.For the sake of brevity, a redundant description is therefore omitted.

[0039] It is understood that the electric machine 362 and the corresponding gear train 367 are optional and may therefore be omitted from the electric axle in alternative embodiments. In such an example, the electric axle 359 includes the electric machine 360, the gear train 363 with two gear pairs, and the transmission 202.

[0040] In general, a variety of gear train layouts may be used connected to the input of the mode planetary gear set. For example, the gear trains used to connect the first electric machine and / or the second electric machine may have fewer or additional gear ratios. In alternative examples, one or more planetary gear sets (e.g., simple planetary gear sets, compound planetary gear sets, and the like) may be used to connect the one or more electric machines to the mode planetary gear set. For example, a planetary gear set coaxial with the electric machine may be used to connect the electric machine to the mode planetary gear set. Additionally or alternatively, a planetary gear set coaxial with the rotational axis of the output shafts 242 and 243 may be used to rotatably couple the electric machine to the mode planetary gear set.In all embodiments where one or more planetary gear sets provide the input connection for the mode planetary gear set, a carrier gear may be anchored in the planetary gear set, a ring gear may be anchored in the planetary gear set, or a sun gear may be anchored in the planetary gear set, in various examples. Additional gear ratios, chains, belts, combinations thereof, and the like may be additionally or alternatively used to transfer mechanical power between the one or more electric machines and the planetary gear set.

[0041] It should further be understood that each of the electric axles described herein may include a second electric machine, if desired. For example, the second electric machine may be coupled to the input of the mode planetary gear set in the same manner as the mechanical connection between the first electric machine and the input of the mode planetary gear set, in one example. In another example, the second electric machine may be coupled to the input of the mode planetary gear set using a different gearing arrangement to enable a different input ratio between the electric machine and the mode planetary gear set, whereby the second electric machine may have different characteristics than the first electric machine.In addition, a separating clutch may be arranged between the second electric machine and the mode planetary gear set to decouple the second electric machine from the mode planetary gear set and thus further increase efficiency in some cases.

[0042] Fig. 3C shows an electric axle 369 with an electric machine 370 arranged perpendicular to the rotational axis of the transmission 202. A gear train 372 with bevel gears 374 provides the input to the mode planetary gear set 204. As with the exemplary electric axle 359 of Fig. 3B, the addition of a second electric machine and a separating clutch for the second electric machine is considered.

[0043] Fig. 3D shows an electric axle 379 with an electric machine 380 arranged perpendicular to the rotational axis of the transmission 202. In the example shown, the electric axle includes an input gear transmission 382 with several reduction gears 383 and 384, which can be switched via a clutch 385. In this way, the selectable gear train in the transmission can be further expanded, which can enable more efficient operation of the electric machine. As with the exemplary electric axle 359 from Fig. 3B, the addition of a second electric machine and a disconnect clutch for the second electric machine is contemplated. However, as previously mentioned, a variety of gear train layouts are contemplated for providing the input to the mode planetary gear set. In addition, bevel gears 387 are provided in the gear train 382 to connect the gear train to the input shaft 388.

[0044] It is understood that electric axles are conceivable that have the features of combined arrangements of gear transmission and / or motor for two or more Fig. 2-3D. Furthermore, any of the various motor and / or input gear arrangements can be used with any of the transmission architectures or combinations of transmission architectures described herein.

[0045] Fig. Figure 4 shows another example of a transmission 400 for an electric axle. In the example shown, the transmission 400 again includes a differential compound planetary gear set with meshing planets 404, a mode planetary gear set 406, and a mode clutch 408. The arrangement of the differential compound planetary gear set with meshing planets 404 and the mode planetary gear set 406 is identical to that of the differential compound planetary gear set with meshing planets 105 and the mode planetary gear set 104 from Fig. 1A. Therefore, a redundant description of the overlapping components is omitted for the sake of brevity.

[0046] Furthermore, in the example from Fig. 4, a simple planetary gear set 410 is directly coupled to a sun gear 412 in the mode planetary gear set 406 via a carrier 413. Furthermore, a sun gear 414 of the simple planetary gear set acts as the input of the transmission. Furthermore, a ring gear 418 is coupled to the simple planetary gear set in the example of Fig. 4. However, other configurations of simple planetary gear sets are also possible. For example, in the simple planetary gear set 410, the ring gear 418 can be coupled to the sun gear 412 in the mode planetary gear set 406, and in the simple planetary gear set 410, the carrier gear 413 can be anchored, and the sun gear 414 of the simple planetary gear set 410 can function as the input of the transmission.

[0047] Fig. Figure 5 shows another example of a transmission 500 for an electric axle. The transmission 500 in the example shown again includes a differential compound planetary gear set with intermeshing planets 502, a mode planetary gear set 504, and a mode clutch 506, similar to the transmission 102 in Fig. 1A. Furthermore, as in Fig. 5, a simple compound planetary gear set with meshing planets 508 is directly coupled to a sun gear 510 in the mode planetary gear set 504 via a carrier 511. A sun gear 512 of the compound planetary gear set with meshing planets 508 acts as the input of the transmission 500. In addition, a ring gear 514 is anchored in the compound planetary gear set with meshing planets 508 ( Fig. 5). However, other configurations of compound meshing planetary gear sets are also possible. For example, in compound meshing planetary gear set 508, ring gear 514 may be coupled to sun gear 510 in mode planetary gear set 504, and in compound meshing planetary gear set 508, carrier gear 511 may be anchored, and sun gear 512 of compound meshing planetary gear set 508 may act as the input of the transmission.

[0048] Fig. 6 shows another example of a transmission 600 for an electric axle. In the example shown, the transmission 600 again includes a differential compound planetary gear set with intermeshing planets 602 and a mode planetary gear set 604 with a mode clutch 605. However, in the example shown, a simple planetary gear set 606 is arranged between the differential compound planetary gear set 602 with intermeshing planets and the mode planetary gear set 604. In the example shown, a sun gear 608 in the simple planetary gear set 606 is rotatably coupled to a ring gear 610 in the mode planetary gear set 604, a carrier gear 611 in the simple planetary gear set 606 is rotatably coupled to a ring gear 612 of the differential compound planetary gear set 602 with intermeshing planets, and a ring gear 614 in the simple planetary gear set 606 is anchored. However, other configurations of planetary gear sets are also possible.For example, in the simple planetary gear set 606, the ring gear 614 may be coupled to the ring gear 612 in the differential compound planetary gear set with intermeshing planets 602, and in the simple planetary gear set 606, the carrier member 611 may be anchored, and the sun gear 608 in the simple planetary gear set 606 may be rotatably coupled to a ring gear 610 in the mode planetary gear set 604.

[0049] Fig. 7 shows another example of a transmission 700 for an electric axle. In the example shown, the transmission 700 again includes a differential compound planetary gear set with intermeshing planets 702 and a mode planetary gear set 704 with a mode clutch 705. The transmission includes another compound planetary gear set with intermeshing planets 706, in which a carrier 708 is rotatably coupled to a ring gear 710 in the differential compound planetary gear set with intermeshing planets 702. The compound planetary gear set with intermeshing planets 706 also includes a sun gear 712 rotatably coupled to a ring gear 714 in the mode planetary gear set 704. Furthermore, in the example shown, a ring gear 716 is anchored in the compound planetary gear set with intermeshing planets 706. However, other configurations of planetary gear sets are also possible, as already mentioned.For example, in the compound meshing planetary gear set 706, the ring gear member 716 may be coupled to the ring gear member 710 in the differential compound meshing planetary gear set 702, and in the compound meshing planetary gear set 706, the carrier member 708 may be anchored, and the sun gear member 712 in the compound meshing planetary gear set 706 may be rotatably coupled to a ring gear member 714 in the mode planetary gear set 704. It is understood that the transmissions in . Fig. 4-7 and the other transmissions described here may contain axle separating clutches and / or differential locking clutches.

[0050] Fig. 8 shows another example of a transmission 800 for an electric axle. In the example shown, the transmission 800 includes a mode planetary gear set 802. However, in the example shown, a ring gear 803 within the mode planetary gear set 802 is rotatably coupled to a limited-slip differential 804 configured to limit the speed differentiation between the output shafts 806 and 808 through a clutch, friction, preload ratios, and / or other suitable devices and methods.

[0051] Fig. 9 shows another example of a transmission 900 for an electric axle. In the example shown, the transmission 900 again includes a differential compound planetary gear set with intermeshing planets 902. The transmission 900 also includes a mode planetary gear set 904 with a different architecture than the previously described mode planetary gear sets. That is, the mode planetary gear set 904 includes a carrier 906 rotatably coupled to a ring gear 908 in the differential compound planetary gear set with intermeshing planets 902. In addition, a sun gear 910 in the mode planetary gear set 904, which meshes with a set of planet gears 912, acts as the input of the mode planetary gear set 904. Further, a mode clutch 914 is configured to anchor the ring gear 920, which meshes with gears in the set of planet gears 912, in a first mode and to rotatably couple the ring gear 920 and the carrier 906 in a second mode.

[0052] Fig. 10 shows another example of a transmission 1000 for an electric axle. In the example shown, the transmission 1000 again includes a mode planetary gear set 1002. However, in the example shown, a ring gear 1003 in the mode planetary gear set 1002 is rotatably coupled to a carrier 1006 in a dual sun differential 1008. In the example shown, the dual sun differential 1008 further includes a first sun gear 1010 and a second sun gear 1012 coupled to the output shafts 1014 and 1018, respectively. The planet gears 1004 mesh with planet gears 1016 and the sun gear 1010, and the planet gears 1016 mesh with the sun gear 1012. The planet gears 1004 and 1016 are rotatably mounted on the carrier 1006.The dual sun differential may be an open differential or a limited-slip differential configured to limit the speed differential between the output shafts 1014 and 1018 through a clutch, friction, preload ratios, and / or other suitable devices and methods. It is understood that the planetary gear sets described herein may be coupled with other types of differentials, such as limited-slip differentials, open differentials, and the like.

[0053] Fig. 11 shows another example of a transmission 1100 for an electric axle. The transmission 1100 again includes a mode planetary gear set 1102 with a mode clutch 1104. The transmission 1100 also includes an open differential 1106 with a differential carrier 1108 driven by a ring gear 1110 in the mode planetary gear set 1102. The differential 1106 further includes differential pinion gears 1120 (which may be referred to as ring gears) rotatably mounted on the differential carrier 1108 and meshing with side gears 1112 (which may be referred to as sun gears). The side gears 1112 are rotatably coupled to output shafts 1114 and 1116. It should be further understood that the transmission 1106 (shown in Fig. 11) and the differentials from Fig. 8 and Fig. 10 examples of double sun differentials are.

[0054] Furthermore, it is understood that the Fig. 1A-11 can be further combined with springs, clutches or cones, cam ramps, helical gears, worm gears, spur gears, viscous couplings, gerotors, and electronic components to create a limited-slip differential (e.g., a torque-sensing limited-slip differential), an automatic torque-bias limited-slip differential, a clutch pack-type limited-slip differential, a bevel gear differential, a dual-sun differential, a reduction differential, etc.

[0055] The output shafts of the electric axles described herein can be coupled directly to drive wheels, wheel-side gear reductions (e.g., planetary gear reductions in the wheel hubs), or other suitable mechanical components in applications requiring a differential output in vehicles (e.g., cars, trucks, boats, off-highway vehicles, commercial vehicles, light vehicles, off-highway vehicles, mining vehicles, rail vehicles, and the like) as well as in other applications (e.g., manufacturing applications such as manufacturing machinery, industrial applications such as industrial machinery, and the like). When the electric axles described herein are used in vehicles, it is understood that the transmissions can be used as transaxles in electric vehicles (EVs) such as fully electric vehicles (e.g., battery-powered vehicles (BEVs)) and hybrid vehicles.For example, in some examples, vehicles utilizing the transmissions described herein may have an internal combustion engine (e.g., a gasoline engine, a compression-ignition engine, combinations thereof, and the like). Furthermore, the electric axles described herein may have an axle disconnect function and / or a differential lock function.

[0056] The gearing in the planetary gear sets described herein may be straight- or helical-toothed. As described above, the second motors in the electric axles described herein are optional. Furthermore, in one example, the gearing used to mechanically couple the motors to the transmission input may be identical and mesh with a final gear on the output centerline. In another example, the gearing associated with the second motor may be different from the gearing associated with the first motor and mesh with the final gear on the output centerline. In another example, the gearing associated with the second motor may include a clutch to decouple the second electric machine from the mode planetary gear set and, in some examples, further increase efficiency.

[0057] Furthermore, in one example, the gear train associated with the second motor may mesh with the gear train associated with the first motor before the final gear on the output centerline. Furthermore, in one example, the gear train associated with the second motor may have a different gear ratio and mesh with the gear train associated with the first motor before the final gear on the output centerline.

[0058] Furthermore, the two-stage planetary gear sets can be Fig. 1A-11 in one application case, have a ratio of 1:1 in one of the modes. However, the electric axle can have a variety of gear ratios that can be selected based on the end-use objectives of the vehicle platform. Accordingly, the ratios from Fig. 1A-11 applications, and other ratios can be used in the electric axes.

[0059] In addition, the exact position and number of bearings in the electric axle architectures in Fig. 2-3D are suggestive and exemplary, and it is understood that other bearing arrangements, types, quantities, etc. may be used in alternative examples.

[0060] It is further understood that the electric axles may utilize one or more transverse motors coupled to the transmission input via hypoid gears or other suitable bevel gears or helical gears. In such an example, the motor may be connected to the hypoid gear via a corresponding pinion gear, and additional gear ratios and / or shiftable gears may be located between the motor and pinion gear. The shiftable gears may, in various examples, be arranged on both parallel countershafts. Furthermore, additional gear ratios may be added to the electric axles if desired. Furthermore, the planetary gear sets described herein may take the form of simple planetary gear sets, compound planetary gear sets with intermeshing planets, compound planetary gear sets with stepped planets, and / or magnetic planetary gear sets.

[0061] It is also understood that the various engine arrangements used in Fig. 2-3D can be used in any of the electrical axes described here, such as in any of the electrical axes of Fig. 1A and 4-11, or combinations of the electric axes. Furthermore, various combinations of motor and transmission structures are conceivable, incorporating multiple features from different embodiments.

[0062] The invention is further described in the following paragraphs. In one aspect, an electric axle system is provided that includes an electric machine; and a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts, and including: a differential rotatably coupled to and positioned coaxially with a mode planetary gear set; and a mode clutch configured to selectively shift the mode planetary gear set into: a first mode in which the mode clutch anchors one of a carrier and a ring gear included in the mode planetary gear set; and a second mode in which the mode clutch rotatably couples the carrier to the ring gear.In one example, the mode planetary gear set may be a compound planetary gear set with meshing planets; and / or the differential may be a differential compound planetary gear set with meshing planets. Further, in one example, the ring gear in the mode planetary gear set may be rotatably coupled to the differential, and a sun gear in the mode planetary gear set may be rotatably coupled to an upstream component that receives mechanical power from the electric machine. In one example, the electric axle system may further include a differential lock clutch configured to selectively rotatably couple a ring gear in the differential to a carrier in the differential to lock rotation of the two output shafts.Further, in one example, a sun gear in the differential compound planetary gear set with meshing planets may be rotatably coupled to a first output shaft in the two output shafts, and a carrier in the differential compound planetary gear set with meshing planets may be rotatably coupled to a second output shaft in the two output shafts. In another example, the electric axle system may further include an axle disconnect clutch configured to selectively disconnect the differential from the mode planetary gear set. In another example, the electric machine may be arranged coaxially, parallel to, or transversely to the mode planetary gear set and the differential. In yet another example, the mode clutch may be a dog clutch.In another example, the electric axle system may further include a simple planetary gear set rotatably coupled to the mode planetary gear set and the differential. In another example, the electric axle system may further include a compound planetary gear set with intermeshing planets rotatably coupled to the mode planetary gear set and the differential.

[0063] In another aspect, a method of operating an electric axle system is provided, comprising operating a mode clutch to: in a first mode, anchor a carrier or a ring gear in a mode planetary gear set; in a second mode, rotatably couple the carrier and the ring gear in the mode planetary gear set; wherein the electric axle system includes: an electric machine; a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts, and including: the mode planetary gear set rotatably coupled to and positioned coaxially with a differential; and the mode clutch; wherein the mode planetary gear set is a compound planetary gear set having intermeshing planets.In one example, the differential may be a compound planetary gear set with intermeshing planets; the ring gear in the mode planetary gear set may be rotatably coupled to a ring gear in the compound planetary gear set with intermeshing planets; and a sun gear and a carrier gear in the compound planetary gear set with intermeshing planets may be rotatably coupled to separate output shafts. In one example, the method further includes operating a differential lock clutch to rotatably couple a ring gear in the differential to a carrier gear in the differential to lock rotation of the two output shafts. In one example, the method may further include operating an axle disconnect clutch to selectively disconnect the mode planetary gear set from the differential gear.

[0064] In another aspect, an electric axle system is provided that includes an electric machine; and a multi-speed transmission rotatably coupled to the electric machine and including: a mode planetary gear set rotatably coupled to and positioned coaxially with a differential compound planetary gear set with intermeshing planets; and a mode clutch configured to selectively shift the mode planetary gear set between a first mode and a second mode. In one example, the mode planetary gear set may include a first ring gear rotatably coupled to a second ring gear in the differential compound planetary gear set with intermeshing planets.In another example, the mode clutch is configured to switch the mode planetary gear set into: the first mode in which the mode clutch anchors a carrier or ring gear included in the mode planetary gear set; and a second mode in which the mode clutch can rotatably couple the carrier to the ring gear in the mode planetary gear set. In one example, the electric axle system can further include a differential lock clutch configured to selectively rotatably couple a ring gear in the differential compound intermeshing planetary gear set to a carrier in the differential compound intermeshing planetary gear set to lock rotation of the two output shafts; and an axle disconnect clutch configured to selectively disconnect the mode planetary gear set from the differential compound intermeshing planetary gear set.In another example, a sun gear in the differential compound planetary gear set with intermeshing planets may be rotatably coupled to a first output shaft; and a carrier in the differential compound planetary gear set with intermeshing planets may be rotatably coupled to a second output shaft. In another aspect, the electric machine and the mode planetary gear set may be coaxially arranged.

[0065] In another embodiment, an electric axle system is provided that includes an electric machine; and a multi-speed transmission rotatably coupled to the electric machine via at least two pairs of gears that are rotatably coupled to two output shafts, and that includes: a differential rotatably coupled to and positioned coaxially with a mode planetary gear set; wherein the mode planetary gear set is a compound planetary gear set having intermeshing planets.

[0066] Fig. 1A-11 shows example configurations with the relative arrangement of the various components. When these elements are in direct contact with one another or are directly coupled, they may be referred to as being in direct contact or directly coupled, respectively, in at least one example. Similarly, elements shown side by side or adjacent to one another may be adjacent to one another or adjacent to one another, in at least one example. For example, components that are in surface-to-surface contact with one another may be referred to as being in surface-to-surface contact. As another example, in at least one instance, elements that are separated from one another with only a space between them and that do not have any other components may be referred to as such.In yet another example, elements depicted above / below, on opposite sides, or to the left / right of each other may be referred to as such, relative to each other. Further, in at least one example, as depicted in the figures, a topmost element or point of an element may be referred to as a "top" of the component, and a bottommost element or point of the element may be referred to as a "bottom" of the component. As used herein, the terms top / bottom, upper / lower, above / below may refer to a vertical axis of the figures and may be used to describe the positioning of elements of the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As a further example, the shapes of the elements depicted in the figures may be referred to as such (e.g., circular, straight, flat, curved, rounded, beveled, angled, or the like). Furthermore, in one example, elements that are coaxial with one another may be referred to as such. Furthermore, in at least one example, the depicted elements that intersect one another may be referred to as intersecting elements or as intersecting elements. Furthermore, an element depicted inside or outside another element may be referred to as such. In other examples, elements that are offset from one another may also be referred to as such.

[0067] Motor and shift control logic / programs, inverters, electronic control units (ECUs), memory, throttle, brake, speed and incline sensors and the like, shift actuators, etc. can be used in all electric axles and transmissions described here.

[0068] Fig. 1A-11 provide a method for operating an electric axle in which the transmission switches between the two modes depending on the vehicle's operating conditions. The method may further effect selective locking of the differential by actuating a differential lock clutch in the differential. The method may also include selectively disconnecting the axle by actuating an axle disconnect clutch.

[0069] Furthermore, the axles and transmissions described herein may include control systems that include a controller having a processor and a memory storing instructions for performing the method steps described herein. More specifically, the control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by a system, including the controller, in combination with the various sensors and actuators. Furthermore, portions of the methods may be physical actions performed in the real world to change the state of a device. The specific routines described herein may represent one or more arbitrary processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like.Thus, the various actions, operations, and / or functions illustrated can be performed in the order shown, in parallel, or in some cases even without them. Accordingly, the order of processing is not mandatory to achieve the features and advantages of the examples described herein, but is provided for convenience of illustration and description. One or more of the actions, operations, and / or functions illustrated may be performed repeatedly depending on the strategy used. Furthermore, the described actions, operations, and / or functions may graphically represent code to be programmed into the non-transitory memory of the computer-readable storage medium in the control system, wherein the described actions are carried out by execution of the instructions in a system including the various hardware components in combination with the electronic controller.One or more of the process steps described here can be omitted if desired.

[0070] Although various embodiments have been described above, these are to be considered examples and not as restrictions or limitations. It is to be understood that the configurations and operations disclosed herein are exemplary in nature, and that these specific examples should not be considered limiting, as numerous variations are possible. For example, the technology described above may be applied to powertrains that include various types of power sources, including various types of electric machines, internal combustion engines, and / or transmissions. The technology may be used as a standalone system or in combination with other power transfer systems that are not applicable to machines and drive systems for tandem axles, electric trailer axles, P4 axles, electric vehicles (e.g., hybrid vehicles, battery vehicles, etc.).), agricultural vehicles or machines, watercraft or machines, motorcycles, recreational vehicles, on- and off-road vehicles, mining vehicles, rail vehicles, production machines, industrial machines, etc. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions, and / or properties disclosed herein. Those skilled in the art will appreciate that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter.

[0071] The following claims particularly point out certain combinations and subcombinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be construed as including the inclusion of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope than the original claims, are also to be considered included within the subject matter of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 63 / 515,673

[0001]

Claims

[1] Electric axle system, which includes: an electrical machine; and a multi-speed gearbox rotatably connected to the electric machine, rotatably connected to two output shafts and including: a differential rotatably coupled to and coaxial with a mode planetary gear set; and a mode clutch configured to selectively switch the mode planetary gear set to: a first mode in which the mode clutch engages a carrier or a ring gear included in the mode planetary gear set; and a second mode in which the mode clutch rotatably couples the carrier to the ring gear. [2] An electric axle system according to claim 1, wherein: the mode planetary gear set is a compound planetary gear set with meshing planets; and / or the differential is a differential compound planetary gear set with intermeshing planets. [3] The electric axle system of claim 2, wherein the ring gear in the mode planetary gear set is rotatably coupled to the differential, and a sun gear in the mode planetary gear set is rotatably coupled to an upstream component that receives mechanical power from the electric machine. [4] The electric axle system of claim 1, further comprising a differential lock clutch configured to selectively rotatably couple a ring gear in the differential to a carrier in the differential to lock rotation of the two output shafts. [5] The electric axle system of claim 3, wherein a sun gear in the differential compound planetary gear set with intermeshing planets is rotatably coupled to a first output shaft in the two output shafts and a carrier in the differential compound planetary gear set with intermeshing planets is rotatably coupled to a second output shaft in the two output shafts. [6] The electric axle system of claim 1, further comprising an axle disconnect clutch configured to selectively disconnect the differential from the mode planetary gear set. [7] The electric axle system of claim 1, wherein the electric machine is arranged coaxially, parallel, or transversely to the mode planetary gear set and the differential. [8] The electric axle system of claim 1, wherein the mode clutch is a dog clutch. [9] The electric axle system of claim 1, further comprising a simple planetary gear set rotatably coupled to the mode planetary gear set and the differential. [10] The electric axle system of claim 1, further comprising a compound planetary gear set having intermeshing planets rotatably coupled to the mode planetary gear set and the differential. [11] The electric axle system of claim 1, wherein the mode planetary gear set includes a first ring gear rotatably coupled to a second ring gear in the differential compound planetary gear set with intermeshing planets. [12] The electric axle system of claim 1, wherein the mode clutch is configured to switch the mode planetary gear set to: the first mode in which the mode clutch engages a carrier or ring gear included in the mode planetary gear set; and the second mode in which the mode clutch rotatably couples the carrier to the ring gear in the mode planetary gear set. [13] An electric axle system according to claim 1, further comprising: a differential lock-up clutch configured to selectively rotatably couple a ring gear in the differential compound planetary gear set with intermeshing planets to a carrier in the differential compound planetary gear set with intermeshing planets to lock rotation of the two output shafts; and an axle disconnect clutch configured to selectively disconnect the mode planetary gear set from the differential compound planetary gear set with intermeshing planets. [14] An electric axle system according to claim 1, wherein: a sun gear in the differential compound planetary gear set with intermeshing planets is rotatably coupled to a first output shaft; and a carrier in the differential compound planetary gear set with intermeshing planets is rotatably coupled to a second output shaft. [15] Electric axle system according to claim 1, wherein the electric machine and the mode planetary gear set are arranged coaxially.

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