Electric axle

Abstract

Electric axle system that includes: a traction motor; a first shaft which is rotaryally coupled to the traction motor via one or more reduction gears; a second shaft, arranged coaxially to the first shaft and rotatably coupled to a differential; and a coupling that is designed for this purpose: to rotaryally couple the first shaft and the second shaft together in a high-speed position; and In a low-speed position, the first shaft with a sun gear in a compound planetary gear set and a ring gear in the compound planetary gear set with the second shaft are synchronized to rotate together; wherein the compound planetary gear set and the differential are arranged coaxially; and the composite planetary gear set includes: a first set of planetary gears meshing with the sun gear; and a second set of planetary gears that mesh with the ring gear.

Description

CROSS-REFERENCE TO RELATED REGISTRATION

[0001] The present application claims priority from U.S. Preliminary Application No. 63 / 703,599 entitled “ELECTRIC AXLE”, which was filed on October 4, 2024. The entire content of the aforementioned application is hereby incorporated by reference for all purposes. TECHNICAL AREA

[0002] The present disclosure relates to an electric axle with a multi-start planetary gear set. BACKGROUND AND DETOUR

[0003] Segments of the vehicle market are moving towards electrification. Inventors have recognized the need to further increase the compactness of the electric powertrain and the power output in a cost-effective package. Attempts have been made to develop electric axles for hybrid and fully electric vehicle platforms. Electric axles comprise motors, transmissions, and differentials that together transmit power to the drive wheels.

[0004] The inventors recognized that certain vehicle platforms require both on- and off-road performance characteristics, which entails undesirable compromises. For example, relatively high torque at low engine speeds may be desirable off-road, leading to lower powertrain efficiency on the road.

[0005] The inventors recognized the aforementioned challenges and developed an electric axle to overcome them, at least partially. In one example, the electric axle system comprises a traction motor, a first shaft rotaryally coupled to the traction motor via one or more reduction gears, and a second shaft arranged coaxially to the first shaft and rotaryally coupled to a differential. The electric axle system further includes a coupling configured to rotaryally couple the first and second shafts in a high-speed position, and in a low-speed position, to rotaryally couple the first shaft to a sun gear in a compound planetary gear set and to a ring gear in the compound planetary gear set to the second shaft. Additionally, the compound planetary gear set and the differential are arranged coaxially in the electric axle system.Furthermore, the compound planetary gear set in the electric axle system comprises a first set of planetary gears that mesh with the sun gear and a second set of planetary gears that mesh with the ring gear. This achieves a modular electric axle architecture in a space-saving layout capable of operating efficiently in both higher and lower speed modes, thus enabling the axle to be used in a wider variety of operating environments. By employing a compound planetary gear set in the electric axle, the traction motor can rotate in one direction while the axle operates in both modes, resulting in a compact package with target gear ratios for both operating modes.

[0006] In one example, the coupling can be configured to, in a neutral position, decouple the sun gear from the first shaft, decouple the ring gear from the second shaft, and decouple the first shaft from the second shaft. This expands the coupling's functionality and allows for a reduction in losses in the electric drive under certain operating conditions, thereby increasing the drive's efficiency.

[0007] In another example, during the shift between the high-speed and low-speed positions, the clutch is moved into a synchronization position, where the rotational speed of the sun gear is synchronized with the rotational speed of the first shaft. This synchronization can occur when shifting at non-zero speeds. This reduces noise, vibration, and harshness (NVH) during shifting operations.

[0008] It should be noted that the foregoing summary serves to present, in simplified form, a selection of concepts that are further explained in the detailed description. It does not serve to identify essential features of the claimed subject matter, the scope of which is defined exclusively by the claims following the detailed description. Furthermore, the claimed subject matter is not limited to implementations that eliminate the disadvantages mentioned above or in any part of this disclosure. BRIEF DESCRIPTION OF THE FIGURES Fig. Figure 1 is a schematic representation of an example of an electric axis. Fig. Figure 2 is a perspective view of an example of an electric axis. Fig. 3A-3B are cross-sectional views of the in Fig. 2 electric axles shown in a configuration with lower or higher gear. Fig. 4A-4C are detailed illustrations of a coupling used in the Fig. The electric axis shown in section 2 is included in different positions. DETAILED DESCRIPTION

[0009] This section describes a multi-speed electric axle that achieves a target gear range for operation at lower speeds (e.g., in off-road environments) and higher efficiency at higher speeds compared to previous electric axle designs. In one example, the multi-speed electric axle includes a coupling configured to rotaryally couple a first shaft and a second shaft (coupled to a differential) in a high-speed position to bypass a compound planetary gear set. Conversely, in a lower-speed position, the coupling is configured to rotaryly couple the second shaft to a sun gear in the compound planetary gear set and to a ring gear in the compound planetary gear set with the second shaft.Furthermore, the electric axle architecture described above allows for higher power density, greater ground clearance, and fewer spatial constraints for the surrounding steering and suspension components. Additionally, the aforementioned electric axle architecture allows for greater modularity, if desired. Furthermore, on certain vehicle platforms, specific reduction gears in the transmission assembly can be removed if required.

[0010] Fig. Figure 1 shows an electric vehicle (EV) 100 comprising a powertrain 102 with an electric axle 104. In this sense, the EV 100 in the example shown is a hybrid EV. Furthermore, in some examples, another axle of the vehicle may be driven by an internal combustion engine and / or the internal combustion engine may be configured to charge a traction battery and / or other suitable energy storage device. In other examples, the EV 100 may even be a pure electric vehicle (e.g., a battery electric vehicle (BEV)) in which the internal combustion engine is omitted.

[0011] As described here, an electric axle is an electric drive integrated into an axle. In one example, the electric axle can be a rigid electric axle. In another example, the electric axle can be an independent axle. Furthermore, a rigid axle is an axle with mechanical components that structurally support each other and run between the drive wheels. For example, in one embodiment, the rigid axle can be a structurally continuous structure extending between the drive wheels along a transverse axis. In this way, wheels coupled to the rigid axle move essentially in unison when the vehicle travels, for example, on uneven road surfaces. More precisely, the camber angle of the wheels can remain essentially constant while the suspension moves during travel. The electric axle 104 can be coupled to a suspension system 107 in one example.The suspension system 107 can be a dependent suspension system, as in the example of the rigid axle. Therefore, the electric axle can be an unsprung mass in the example of the rigid axle. However, in the example of the independent suspension, the suspension system 107 can be an independent suspension system.

[0012] The electric axle 104 includes a traction motor 106. The traction motor 106 can, for example, be an electric motor-generator. The traction motor 106 can, for instance, be designed as a multi-phase AC motor-generator. In this way, the traction motor 106 and the other traction motors described here can be operated in a regeneration mode. However, in other examples, the electric machine can be a motor without the capabilities of a generator.

[0013] As in Fig. As shown in Figure 1, the traction motor 106 can be electrically coupled to an inverter 108. The inverter 108 is configured to convert direct current (DC) electrical power into alternating current (AC) electrical power and vice versa. Therefore, as mentioned earlier, the traction motor 106 can be an AC machine. In other examples, however, the electric machine can also be a DC machine, and the inverter can be omitted from the electric drive in this case. The inverter 108 can receive electrical energy from one or more energy storage devices 110 (e.g., traction batteries, capacitors, combinations thereof, and the like). The arrows 112 indicate the electrical energy transfer between the traction motor 106, the inverter 108, and the energy storage device(s) 110, which occurs during the various operating modes of the electric axle (e.g.,a driving mode and a regeneration mode). In a driving mode, electrical energy can flow from the energy storage device(s) 110 to the traction motor 106, and in a regeneration mode, electrical energy can flow in the opposite direction from the electric machine to the energy storage device(s). In one example, the inverter 108 can be integrated into the electric axle 104.

[0014] The traction motor 106 comprises a stator 118 and a rotor 120 with a rotor shaft 122. The electric axle 104 also includes a gear train 123. In the example shown, the rotor shaft 122 is directly rotaryally coupled to an input shaft 124. However, in other examples, other suitable mechanical connections can be used to connect the traction motor to the gearbox.

[0015] In the example shown, the transmission assembly 123 comprises a first reduction gear 126 and a second reduction gear 128. However, in alternative examples, the transmission 123 can also include a larger or smaller number of reduction gears. The number of reduction gears can be selected based on the target gear ratios for the various operating modes of the axle.

[0016] The first reduction gear 126 comprises a gear 130 that is rotaryally coupled to the input shaft 124, so that it rotates with it. Another gear 132 of the first reduction gear 126 is rotaryally coupled to an intermediate shaft 134, so that it rotates with it. It is understood that gear 130 meshes with gear 132. The gears described here can be, for example, helical or spur gears.

[0017] The second reduction gear 128 comprises a gear 136 which is rotaryally coupled to the intermediate shaft 134 so that it rotates with it. The second reduction gear 128 comprises another gear 138 which is rotaryally coupled to a shaft 140 so that it rotates with it. It is understood that gear 136 meshes with gear 138.

[0018] The electric axle 104 also includes a coupling 142 and a compound planetary gear set 144. The compound planetary gear set comprises a sun gear, a ring gear, and two or more sets of meshing planet gears, as well as a carrier on which the planet gears rotate. In the example of the compound planetary gear set, one set of planet gears meshes with the sun gear, while another set of planet gears meshes with the ring gear.

[0019] As described here, the coupling 142 is configured, in a first position, to rotaryally couple shaft 140 and shaft 143, which serves as the input for a differential 145, when the electric axle is operated in a drive mode and a regeneration mode. In this way, the mechanical power flow through the electric axle bypasses the planetary gear set 144, thereby increasing the axle's operating efficiency by avoiding losses in the compound planetary gear set. In a second position, the coupling 142 is configured to rotaryally couple shaft 140 and a sun gear in the planetary gear set 144, and to rotaryally couple a ring gear in the planetary gear set and shaft 143. In this way, the mechanical force is routed through the compound planetary gear set to achieve the desired reduction gear ratio.The coupling 142 can also be configured to operate in a neutral position in which the power flow from the shaft 140 to the downstream components is blocked and vice versa. For example, the coupling 142 can be operated in a neutral position during coasting and flat towing.

[0020] The axle shafts 146 and 148 are rotaryally coupled to the differential 145 and the drive gears 150 and 152. The axle shaft 146 passes through central openings in the planetary gear set 144 and the shaft 140.

[0021] The EV 100 can also include a control system 180 with a controller 182. The controller 182 comprises a processor 184 and a memory 186. The memory 186 contains instructions stored within it, which, when executed by the processor 184, cause the controller 182 to perform the various procedures, control techniques, etc., described herein. The processor 184 can include a microprocessor unit and / or other types of circuitry. The memory 186 includes known data storage media, such as random access memory, read-only memory, keep-alive memory, combinations thereof, etc.

[0022] The controller 182 can receive various signals from sensors 188 located at different points on the vehicle 100, and in particular on the electric multi-gear axle 104. These sensors may include a speed sensor for the electric motor, temperature sensors for the energy storage system, sensors for the clutch position, sensors for the state of charge of the energy storage system, wheel speed sensors, and the like. The controller 182 can also send control signals to various actuators 190 coupled at different points on the electric vehicle 100, as well as to the electric multi-gear axle 104. For example, the controller 182 can send signals to the inverter 108 to adjust the speed of the traction motor 106. The other controllable components in the vehicle and the powertrain can function similarly with regard to command signals and actuator adjustment.For example, the controller 182 can send signals to the coupling 142 to move the coupling into different positions and operate the axis in various operating modes, which will be discussed in more detail below. This is described in... Fig. The control system shown in Figure 1 can also be used in the other examples for electric axles described here. Furthermore, the control system can be configured to command gear changes between the individual gears of a multi-speed transmission via clutch commands.

[0023] The EV 100 can also include one or more input devices 192 (e.g., an accelerator pedal, a brake pedal, a gear, a differential lock actuator, a console instrument panel, a touch interface, a touch panel, a keyboard, combinations thereof, and the like) in electronic communication with the controller 182. The input device(s) 192 can, in response to operator input, generate a request for acceleration adjustment, a request to shift gears if the electric axle includes a multi-speed transmission, and similar actions.

[0024] In Fig. 1 as well as in the Fig. Figure 2-4C shows a system of axes that can be referenced if necessary. The z-axis can be a vertical axis (e.g., parallel to a gravitational axis), the y-axis can be a lateral axis (e.g., a horizontal axis), and / or the x-axis can be a longitudinal axis, in one example. In other examples, however, the axes may have different orientations.

[0025] Fig. Figure 2 shows an example of an electric axle 200. The electric axle 200 serves as an example for the in Fig. 1. Electric axis 104 shown. Therefore, at least some of the structural and functional features of the electric axis 104 can be adopted into the electric axis 200 and vice versa.

[0026] The electric axle 200 comprises a traction motor 202 with a rotor shaft 204, which is rotaryally coupled to an input shaft 206. The electric axle 200 in turn comprises a gear train 208 with a first reduction gear 210 and a second reduction gear 212. The first reduction gear 210 comprises a gear 214, which is rotaryally coupled to the input shaft 206, and a gear 216, which is rotaryally coupled to an intermediate shaft 218. The second reduction gear 212 comprises a gear 220, which is rotaryly coupled to the intermediate shaft 218, and a gear 222, which is rotaryly coupled to a shaft 224.

[0027] In the illustrated example, the shaft 224 extends through a central opening 226 of a planetary gear set 228. Specifically, the shaft 224 is coupled to a clutch 230. As already indicated, the clutch is designed to operate in several positions, allowing the electric axle to operate in different modes, which here refer to the Fig. 3A and Fig. Section 3B will be discussed in more detail. In general, the modes include a higher-speed mode, a lower-speed mode, a neutral mode, and a synchronization mode that may occur during switching transients.

[0028] The coupling 230 is designed so that it can be optionally coupled to a shaft 232, which serves as a rotary connection to a differential 234. The coupling 230 comprises several couplings (e.g., sleeves) to achieve the various operating modes, which will be discussed in more detail here.

[0029] The differential 234 is configured to transmit mechanical power to the drive wheels, as indicated by arrows 236. The planetary gear set 228 comprises a sun gear 238, a first group of planet gears 240 meshing with the sun gear 238, a second group of planet gears 242 meshing with a ring gear 244, and a carrier 246. The planet gears 240 and 242 are rotatably mounted on the carrier 246.

[0030] In the example shown, bearings 248 are connected to the rotor shaft 204, bearings 250 to the input shaft 206, bearings 252 to the intermediate shaft 218, bearings 254 to the shaft 224, bearings 256 to the planetary gear set 228, and bearings 258 to the differential. In one example, bearings 256 can be conceptually included within the planetary gear set 228. Alternatively, one of bearings 256 can be located between the carrier 246 and the ring gear 244.

[0031] The coupling 230 is arranged axially between the differential 234 and the compound planetary gear set 228. This increases the space efficiency of the axle.

[0032] The Fig. 3A and Fig. Figure 3B shows the mechanical power paths through the electric axle 200 in a lower and a higher gear range, respectively. The lower gear range can be described as the higher speed mode, and the higher gear range as the lower speed mode.

[0033] In Fig. In position 3A, the coupling 230 is in a position where the shaft 224 is rotaryally coupled to the sun gear 238 and the ring gear 244 is rotaryly coupled to the shaft 232. Conversely, the coupling 230 is in Fig. 3B in a position in which shaft 224 is rotaryally coupled to shaft 232, so that the power flow is routed past the planetary gear set 228.

[0034] The in the Fig. 3A and Fig. The mechanical power paths 300 and 302 shown in Figure 3B each lead from the traction motor 202 to the first reduction gear 210, from the first reduction gear to the second reduction gear 212, and from the second reduction gear to the shaft 224. Power transmission through the transmission train 208 takes place via the input shaft 206, the intermediate shaft 218, and the gears 214, 216, 220, and 222.

[0035] As in Fig. As shown in 3A, the power path 300 runs from the shaft 224 to the clutch 230, from the clutch 230 to the sun gear 238, from the sun gear to the planet gears 240, from the planet gears 240 (e.g. inner planet gears) to the planet gears 242 (e.g. outer planet gears), from the planet gears 242 to the ring gear 244, from the ring gear to the clutch 230, from the clutch 230 to the shaft 232, from the shaft 232 to the differential 234 and from the differential 234 via the axle shafts to the drive wheels.

[0036] As in Fig. As shown in Figure 3B, the power path 302 runs from the shaft 224 to the coupling 230, from the coupling to the shaft 232, from the shaft 232 to the differential 234 and from the differential to the drive wheels via the axle shafts.

[0037] The rotary axes 380, 382, ​​384, 386, 388 and 390 of the traction motor 202, the input shaft 206, the intermediate shaft 218, the shaft 224, the shaft 232 and the differential 234 are in the Fig. 3A-3B shown for reference. As in Fig. Figures 3A-3B show axes 386, 388 and 390 arranged coaxially to each other.

[0038] The Fig. Figures 4A-4C show detailed views of the coupling 230 in different positions. The shaft 224 and the planetary gear 228 are shown in the Fig. Figures 4A-4C illustrate this. The shaft 224 comprises a splined section 400 with a splined section 402 that engages with a splined section 404 in a coupling sleeve 406 (e.g., an inner coupling sleeve) of the coupling 230. A bearing 408 is connected to the coupling sleeve 406 of the coupling 230 and to a coupling sleeve 410 (e.g., an outer coupling sleeve) of the coupling. In this way, the coupling sleeve 406 and the coupling sleeve 410 rotate independently of each other. The bearing 408 is therefore arranged radially between the coupling sleeves 406 and 410.

[0039] Naturally, the coupling sleeves of the clutch can be controlled independently of each other. This allows the coupling sleeves to be moved axially to their various positions individually or in a coordinated manner, depending on the shifting strategy. The shaft 232 is also in Fig. 4A-4C are shown. Carrier 246 is in the Fig. 4A-4C together with a coupled bearing 411. An extension 413 of the ring gear 244 is shown in Fig. Figures 4A-4C are shown. Actuators 450 and 452 can be configured to actuate coupling sleeves 406 and 410 independently of each other.

[0040] Fig. Figure 4A shows in particular the inner coupling sleeve 406 with a splined section 412, which engages with a splined section 414 in a section 416 of the shaft 232. In this way, the force is transmitted from the shaft 224 via the coupling 230 to the shaft 232, thus bypassing the planetary gear set 228. This decouples the outer coupling sleeve 410 from the planetary gear set 228. Fig. Figure 4A therefore shows the clutch 230 in a position where the electric axle is placed in a higher-speed mode in which the compound planetary gear set is bypassed, thus preventing the planetary gear set from providing a further reduction gear. The higher-speed mode can therefore be described as a second gear, which can be used when driving at higher speeds.

[0041] Fig. Figure 4B shows the coupling 230 with the inner coupling sleeve 406, which engages with the sun gear 238 via a splined connection 418 that meshes with a splined connection 420 in the sun gear. Specifically, the splined connection 418 is contained within an axial extension 422 of the sun gear 238. As shown in Fig. As shown in Figure 4B, the outer coupling sleeve 410 of the coupling 230 also includes a splined shaft 424 which engages with a splined shaft 426 in the extension 413 of the ring gear 244. In the example shown, the splined shaft 426 is arranged on an inner circumference 428 of the extension 413 of the ring gear 244. In this way, the coupling 230 is in a position in which the mechanical force is transmitted from the shaft 224 to the sun gear 238 in the planetary gear set and from the ring gear 244 to the shaft 232. Fig. Figure 4B therefore shows the clutch 230 in a position where the electric axle is engaged in a lower-speed mode, in which the compound planetary gear set provides a further reduction gear. This lower-speed mode can therefore be described as a first gear, which can be used when driving at lower speeds, such as off-road.

[0042] Fig. Figure 4C shows the coupling 230 in a synchronization position in which the splined shaft 418 begins to engage with the splined shaft 420, while the outer coupling sleeve 410 is decoupled from the extension 413 of the ring gear 244. In this way, the rotational speed of the shaft 224 can be adjusted to the rotational speed of the sun gear 238 of the compound planetary gear set.

[0043] It is further understood that the clutch 230 can be switched to a neutral position in which the inner clutch sleeve 406 is decoupled from the planetary gear set 228 and the shaft 232, and the outer clutch sleeve 410 is decoupled from the planetary gear set 228. In this way, the power transmission from the output shaft to the downstream components can be selectively prevented. When the clutch 230 is switched to the synchronization position, the ring gear 244 and the input of the differential are speed-matched. In this way, noise, vibration, and harshness (NVH) during gear changes are reduced.

[0044] It is understood that the in the Fig. The coupling sleeves 406 and 410 shown in Figures 4A-4C can be brought into positions in which the sun gear 238 is decoupled from the coupling sleeve 406, so that the splines 418 and 420 are not in engagement, and in which the coupling sleeve 410 is decoupled from the extension 413 of the ring gear 244, so that the splines 424 and 426 are not in engagement. This coupling configuration is, as already mentioned, referred to as the neutral position. This neutral position of the coupling makes it possible to reduce losses in the electric axle and thus increase the efficiency of the electric axle under certain conditions.

[0045] During a shift from the low-speed to the high-speed position, the clutch can move from the low-speed position to a neutral position, in which it is disengaged from the sun gear and ring gear. Subsequently, the clutch can move to the synchronization position and then from the synchronization position to the high-speed position (depending on the last gear engaged). This shifting process can also be reversed to change from the higher-speed to the lower-speed mode. The clutch positions in these modes can be described as such.

[0046] The Fig. Figures 2-4C are drawn approximately to scale, except for the schematically represented components. However, in other embodiments, the components may have different relative dimensions.

[0047] As already mentioned, the term rotary coupled refers to a connection between components that enables torque transmission (and thus a mechanical power flow) between them.

[0048] The Fig.Figures 1-4C show example configurations with the various components positioned relative to each other. In other embodiments, however, the components may have different size ratios. It is clear that when these elements are in direct contact with each other or are directly coupled, they can be described as directly touching or directly coupled, at least in one example. Similarly, elements shown side by side or adjacent to each other can be described as side by side or adjacent to each other, at least in one example. For instance, components that are in planar contact with each other can be described as being in planar contact. As a further example, in at least one case, elements that are separated from each other, with only a gap between them and that have no other components, can be described as such.In yet another example, elements that are displayed above / below each other, on opposite sides, or to the left / right of each other can be described as such, relative to one another. Furthermore, in at least one example, as shown in the figures, a topmost element or the highest point of an element can be referred to as the "top" of the component, and a bottommost element or the lowest point of the element can be referred to as the "bottom" of the component. The terms top / bottom, upper / lower, and above / below used here can refer to a vertical axis of the figures and be used to describe the positioning of elements within 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 can be described as such (e.g., circular, straight, planar, curved, rounded, beveled, angled, and the like). Furthermore, in one example, elements that are coaxial with each other can be described as such. In addition, the depicted elements that intersect each other can be described as intersecting elements or as mutually intersecting elements in at least one example. Moreover, an element that is depicted inside or outside another element can be described as such. In other examples, elements that are offset from each other can also be described as such. In still other examples, elements that are arranged coaxially or parallel to each other can be described as such.

[0049] The invention is described in more detail in the following paragraphs. In one aspect, an electric axle is provided comprising a traction motor, an output shaft rotatably coupled via one or more reduction gears, and a coupling system configured to: rotatably couple the output shaft and a differential in a high-speed position; and, in a low-speed position, rotatably couple the output shaft to a sun gear in a planetary gear set and to a ring gear in the planetary gear set to the differential; wherein the traction motor is parallel to and offset from the planetary gear set; and wherein the planetary gear set and the differential are arranged coaxially. In one example, the coupling system can be configured to rotatably decouple the output shaft and the differential in a neutral position.In another example, the clutch system may be configured to synchronize the rotational speeds of the sun gear in the planetary gear set and the output shaft in a synchronization position. In another example, the planetary gear set may be a compound planetary gear set. In yet another example, the compound planetary gear set may comprise a first set of planet gears meshing with the sun gear; and a second set of planet gears meshing with the ring gear. In another example, the differential may be an electronic limited-slip differential. In another example, the electric axle may be a solid axle. In yet another example, the one or more reduction gears may comprise a first and a second reduction gear. In yet another example, the first and second reduction gears may each comprise a gear rotationally mounted on an intermediate shaft.In another example, the coupling system can be arranged axially between the planetary gear set and the differential.

[0050] In another aspect, an electric rigid axle is provided, comprising a traction motor and an output shaft rotaryally coupled via one or more reduction gears; a coupling system configured to: rotaryally couple the output shaft and a differential in a high-speed position; rotaryally couple the output shaft to a sun gear in a planetary gear set and a ring gear in the planetary gear set to the differential in a low-speed position; rotaryly decouple the output shaft and the differential in a neutral position; and synchronize a rotational speed of the sun gear and the output shaft in a synchronization position; wherein the traction motor is parallel to and offset from the planetary gear set; and wherein the planetary gear set and the differential are arranged coaxially. An example may be a compound planetary gear set comprising multiple sets of planet gears.In another example, the differential can be an electronic limited-slip differential. In yet another example, the clutch system can include an inner clutch sleeve with internal splines that mesh with the splines of the output shaft. In yet another example, the inner clutch sleeve can have splines that optionally mesh with splines on a shaft that is directly rotationally coupled to the differential. In yet another example, the clutch system can include an outer clutch sleeve with internal splines that optionally mesh with splines on a component that is directly connected to the ring gear. In yet another example, the clutch system can include a bearing connected to both the inner and outer clutch sleeves.In another example, the one or more reduction gears may comprise a first and a second reduction gear; and the second reduction gear and the clutch system may be located on opposite axial sides of the planetary gear set. In another example, the first and second reduction gears may each comprise a gear rotationally mounted on an intermediate shaft. In yet another example, the differential may be an electronically limited-slip differential.

[0051] In another aspect, an electric axle system is provided comprising a traction motor, a first shaft rotaryally coupled to the traction motor via one or more reduction gears, a second shaft arranged coaxially to the first shaft and rotaryally coupled to a differential, and a coupling configured to: rotaryally couple the first shaft and the second shaft in a high-speed position; and rotaryally couple the first shaft to a sun gear in a compound planetary gear set and a ring gear in the compound planetary gear set to the second shaft in a low-speed position; wherein the compound planetary gear set and the differential are arranged coaxially; and wherein the compound planetary gear set comprises: a first set of planet gears meshing with the sun gear; and a second set of planet gears meshing with the ring gear.In one example, the electric axle system may also include a control unit configured to switch the clutch between the high-speed and low-speed positions. In another example, during the switch between the high-speed and low-speed positions, the clutch may be moved into a synchronization position in which the rotational speed of the sun gear is synchronized with the rotational speed of the first shaft. In yet another example, in the high-speed position, the clutch may rotationally decouple the sun gear from the first shaft and the ring gear from the second shaft. In yet another example, in a neutral position, the clutch rotationally decouples the sun gear from the first shaft, the ring gear from the second shaft, and the first shaft from the second shaft.In another example, the differential can be an electronic limited-slip differential. In another example, the electric axle can be a rigid axle. In another example, the coupling can be arranged axially between the planetary gear set and the differential. In another example, the coupling can include a first coupling sleeve comprising: an internal spline that meshes with a spline on the first shaft; a spline that optionally meshes with a spline on the second shaft; and a spline that optionally meshes with the sun gear. In another example, the coupling can include a second coupling sleeve comprising: an internal spline that meshes with a spline on the second shaft, and a spline that optionally meshes with a spline on the ring gear.

[0052] Another aspect is an electric rigid axle comprising: a traction motor; a first shaft rotaryally coupled to the traction motor via several reduction gears; a second shaft arranged coaxially to the first shaft and rotaryally coupled to a differential; and a clutch configured to rotaryally couple the first and second shafts in a high-speed position; and in a low-speed position to rotaryally couple the first shaft to a sun gear in a compound planetary gear set and to rotaryally couple a ring gear in the compound planetary gear set to the second shaft; and to operate in a neutral position in which the clutch: rotaryally decouples the sun gear from the first shaft; rotaryly decouples the ring gear from the second shaft; and rotaryly decouples the first shaft from the second shaft; wherein the compound planetary gear set and the differential are arranged coaxially;and wherein the compound planetary gear set comprises: a first set of planet gears meshing with the sun gear; and a second set of planet gears meshing with the ring gear. In an example, the coupling may include a coupling sleeve comprising: an internal spline meshing with a spline on the first shaft; a spline meshing optionally with a spline on the second shaft;and a splined connection that optionally engages with the sun gear. In another example, the coupling can include a coupling sleeve comprising: an internal splined connection that engages with a splined connection on the second shaft, and a splined connection that optionally engages with a splined connection on the ring gear. In another example, the differential can be an electronic limited-slip differential. In yet another example, the coupling can be arranged axially between the planetary gear set and the differential.

[0053] In another aspect, a method for operating an electric axle system is provided, comprising the transition of a coupling between a high-speed position and a low-speed position; wherein the electric axle system comprises: a traction motor; a first shaft rotaryally coupled to the traction motor via one or more reduction gears; a second shaft arranged coaxially to the first shaft and rotaryally coupled to a differential; and wherein, in the high-speed position, the coupling rotaryally couples the first shaft and the second shaft; and wherein, in the low-speed position, the coupling rotaryally couples the first shaft to a sun gear in a compound planetary gear set and a ring gear in the compound planetary gear set to the second shaft; wherein the compound planetary gear set and the differential are arranged coaxially;and wherein the compound planetary gear set comprises a first set of planet gears meshing with the sun gear; and a second set of planet gears meshing with the ring gear. In an example, the clutch can be brought into a synchronization position during switching between the high-speed position and the low-speed position, in which the rotational speed of the sun gear is synchronized with the rotational speed of the first shaft. In an example, the clutch can include a first clutch sleeve comprising: an internal spline meshing with a spline on the first shaft; a spline meshing optionally with a spline on the second shaft; and a spline meshing optionally with the sun gear; and the clutch includes a second clutch sleeve comprising: an internal spline meshing with a spline on the second shaft;and a splined connection that optionally engages with a splined connection on the ring gear. In another example, the coupling can be arranged axially between the planetary gear set and the differential. In yet another example, the first coupling sleeve and the second coupling sleeve can be actuated independently of each other.

[0054] In another representation, a multi-speed electric axle is provided, comprising two reduction gears rotaryally coupled to a compound planetary gear set, which is rotaryally coupled to a differential and a clutch arrangement configured to route power around the compound planetary gear set in a lower gear mode and to route power through the compound planetary gear set in a higher gear mode.

[0055] It should be noted that the example control and estimation routines contained herein can be used with various powertrain, transmission, and / or vehicle system configurations. The control methods and routines disclosed herein can be stored as executable instructions in non-volatile memory and executed by the control system, including the controller, in combination with the various sensors, actuators, and other system hardware. Furthermore, the described actions, operations, and / or functions can graphically represent code to be programmed into the non-volatile memory of the computer-readable storage medium in the vehicle controller, with the described actions being executed by carrying out the instructions in a system that includes the various hardware components in combination with the electronic controller.One or more of the procedural steps described here can be omitted if desired.

[0056] Although various embodiments have been described above, it should be understood that these are to be considered examples and not limitations. Those skilled in the art will recognize that the disclosed subject matter can be implemented in other specific forms without departing from the spirit of the subject matter. The embodiments described above are therefore to be regarded in every respect as illustrative and not as limiting. Thus, these specific examples are not to be understood as limiting, since numerous variations are possible. The technology described above can, for example, be applied to powertrains that include various types of power sources, including different types of electric motors and internal combustion engines.The subject matter of this 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.

[0057] The following claims highlight in particular certain combinations and subcombinations that are to be considered novel and not obvious. These claims may refer to "one" element or "a first" element, or the equivalent thereof. Such claims are to be understood as including one or more such elements, with two or more such elements neither required nor excluded. 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 they have a broader, narrower, the same, or different scope than the original claims, are also to be considered as included in the subject matter of the present disclosure. QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] US 63 / 703,599

[0001]

Claims

[1] Electric axle system comprising: a traction motor; a first shaft which is rotaryally coupled to the traction motor via one or more reduction gears; a second shaft, arranged coaxially to the first shaft and rotatably coupled to a differential; and a coupling that is designed for this purpose: to rotaryally couple the first shaft and the second shaft together in a high-speed position; and In a low-speed position, the first shaft with a sun gear in a compound planetary gear set and a ring gear in the compound planetary gear set with the second shaft are synchronized to rotate together; wherein the compound planetary gear set and the differential are arranged coaxially; and the composite planetary gear set includes: a first set of planetary gears meshing with the sun gear; and a second set of planetary gears that mesh with the ring gear. [2] Electric axle system according to claim 1, further comprising a control unit configured to: to switch the clutch between the high-speed position and the low-speed position. [3] Electric axle system according to claim 2, wherein during the switching of the clutch between the high-speed position and the low-speed position the clutch is moved into a synchronization position in which a speed of the sun gear is synchronized with a speed of the first shaft. [4] Electric axle according to one of the preceding claims, wherein in the high-speed position the coupling rotatably decouples the sun gear from the first shaft and the ring gear from the second shaft. [5] Electric axle according to any of the preceding claims, wherein the coupling is in a neutral position: the sun wheel rotates independently of the first shaft; the ring gear is decoupled from the second shaft; and the first shaft is rotatably decoupled from the second shaft. [6] Electric axle system according to one of the preceding claims, wherein the differential is an electronic locking differential. [7] Electric axle system according to any of the preceding claims, wherein the electric axle is a rigid axle. [8] Electric axle according to one of the preceding claims, wherein the coupling is arranged axially between the compound planetary gear set and the differential. [9] Electric axle system according to any of the preceding claims, wherein the coupling has a first coupling sleeve comprising: an internal splined connection that meshes with a splined connection of the first shaft; a splined connection that optionally engages with a splined connection on the second shaft; and a wedge-shaped toothing that optionally engages with the sun gear. [10] Electric axle system according to claim 9, wherein the coupling has a second coupling sleeve comprising: an internal splined connection that meshes with a splined connection on the second shaft; and a splined connection that optionally meshes with a splined connection of the ring gear.

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