Electric axle

Abstract

Electric axle system, including: an electric machine; a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts, and comprising: a Ravigneaux gear set rotatably coupled to a differential and arranged coaxially to it; and a mode coupling that is set up, optionally: to identify a carrier or a ring gear in the Ravigneaux wheelset; to identify a sun wheel in the Ravigneaux gear set; and to rotatably couple the carrier or the ring gear with the sun gear in the Ravigneaux gear set.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Application No. 63 / 515,760, 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] The present description generally relates to an electric axle with two concentric planetary gear sets. STATE OF THE ART AND SUMMARY

[0003] Electric axles have been deployed in a wide variety of vehicle platforms to meet the electrification needs of various 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 into the vehicle platform compared to electric drives, where the traction motor, transmission, and drive axles are designed as separate units.

[0004] At least some electric axles have not met the end-use design goals for space efficiency, shifting functionality, and power density. For example, some multi-speed transmissions utilize numerous parallel shafts and gears, which pose packaging challenges. Furthermore, in previous multi-speed transmissions, all gearing is meshed, 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 winding losses. Inventors therefore recognized a need to reduce the package size 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 Ravigneaux gear set rotatably coupled to and coaxial with a differential. The multi-speed transmission further includes a mode clutch configured to selectively switch the multi-speed transmission between a first mode, a second mode, and a third mode. In this way, the Ravigneaux gear set effectively achieves three gear ratio modes in a space-efficient design, expanding the system's shifting capabilities.

[0006] In one example, the differential is a compound planetary gear set with differentially meshing planets. This achieves a space-efficient electric axle with a desired power density. More specifically, the use of the compound planetary gear set with differentially meshing planets and the Ravigneaux gear set in this electric axle design allows the use of additional shafts (e.g., countershafts with idler gears) to be omitted if desired, while still achieving a desired number of gear 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 second 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 Ravigneaux gear set from the differential. This expands the functionality of the electric axle to enable differential locks and axle disconnects, further increasing its customer appeal.

[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 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. BRIEF DESCRIPTION OF THE CHARACTERS The Fig. 1A-1B show an example of an electric axle with a compound planetary gear set with differentially meshing planets, a Ravigneaux gear set comprising two sets of planetary gears, one of which is a single planetary gear, and a mode clutch. The Fig. 2A-2B show an example of an electric axle with a compound planetary gear set with differentially meshing planets, a Ravigneaux gear set with two planetary gear sets, one of which is a stepped planet, and a mode clutch. The Fig. 3A-3E show various examples of electric machines and input gear train architectures for the Fig. Electrical axis shown in 1A-1B. The Fig. 4-7 show various examples of a transmission for an electric axle with a compound planetary gear set with differentially meshing planets and a Ravigneaux gear set rotatably coupled to another planetary gear set in various configurations. Fig. Figure 8 shows another example of an electric axle with a Ravigneaux gear set and a limited-slip differential. Fig. Figure 9 shows another example of an electric transmission with a multi-gear Ravigneaux gear set and a compound planetary gear set with differentially meshing planets. Fig. Figure 10 shows another example of an electric axle with a Ravigneaux gear set and a double sun gear differential. Fig. Figure 11 shows another example of an electric axle with a Ravigneaux gear set and an open differential. DETAILED DESCRIPTION

[0009] A multi-gear, differential electric axle with mode selection functionality that achieves greater compactness and power density is described here. Previous multi-gear electric axles utilize multiple parallel shafts, which presents challenges for installation. For example, some multi-gear electric axles use at least two shafts for gear shifting. In these electric axles, the entire gearing is meshed, 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, mesh, and winding losses. Furthermore, spider-gear differentials are comparatively wide and can present challenges for axial installation in certain vehicles, limiting the differential's applicability.Certain planetary differentials, such as compound planetary differentials with two output sun gears or two output ring gears, two side-by-side concentric simple planetary gear sets, and two nested concentric planetary gear sets, can also present challenges related to the axial length and / or overall diameter of the drive axle. However, the above types of planetary gears 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 the sun gear and rotate on the carrier gear. Each planet gear meshes with both the sun gear and the ring gear. Further, as described herein, a compound planetary gear set with intermeshing planets 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 the sun gear and are circumferentially aligned in the same plane as the ring gear and the sun gear. The planetary sets include an inner planet gear 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 goals of space efficiency and power density, in one example, the electric axle includes a transmission featuring a multi-speed planetary gear set with mode selection and a compact planetary differential in a coaxial configuration. Specifically, the multi-speed gear set in the transmission includes a Ravigneaux gear set with a mode clutch for switching between gear modes. Furthermore, the differential planetary gear set in the transmission is a compound planetary gear set with intermeshing planets.

[0012] In one example, the electric axle includes differential and multi-speed planetary gear sets concentric with the output axle of the electric axle. Further, the differential in the electric axle may be formed from a compound planetary gear train with intermeshing planetary gears. The use of the mode and differential planetary gear sets allows multiple shafts used for gear shifting to be omitted from the system, if desired. This increases packaging efficiency, reduces the width of the differential, and reduces the overall axial length of the electric axle, if desired, allowing for a more compact and high-performance 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.More specifically, the system must be free of idle passages that cause bearing, mesh, and winding losses during adjacent speed modes. This increases transmission efficiency.

[0013] When the multi-gear (e.g., three-gear) differentiating electric axle is in one of the two lower modes (e.g., a first or a second mode), there is a relative speed between the elements of the mode planetary gear set. In the third mode, the mode planetary gear set may be locked and rotate as a unit. The differential planetary gear set may also rotate as a unit and only differentiates when the vehicle turns. In practice, the transmission is likely to operate in the highest mode for a larger portion of its operating life than in the other modes (e.g., most of the time). In the highest mode, the planetary gear sets rotate as a unit.Because the components within the differential planetary gear set do not rotate relative to each other, and the components within the multi-gear planetary gear set do not rotate relative to each other, meshing noise is reduced, gear wear is reduced, component life is increased, friction losses are reduced, and winding losses are reduced, thus increasing the overall efficiency of the axle. With increased life and a multiple arrangement 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.In certain end-use operating scenarios where the electric axle can be operated in the highest mode for longer than the other modes and without relative speed with the meshing planetary pairs, it is also possible to use spur gears in the planetary gear sets, which further reduces the cost and complexity of the electric axle and also simplifies the manufacturing of the components of the differential planetary gear set and the multi-speed mode planetary gear set.

[0014] The multi-gear differential electric axle layouts described here allow for the simple and effective integration of axle separation and differential lock features into the axle, if desired. This enables the electric axles to achieve additional features that are difficult to accommodate with other axle architectures, such as a parallel-axis differential design. Furthermore, it should be 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 illustrated example, further includes a compound planetary gear set with differentially meshing planets 105. The mode planetary gear set 104 and the compound planetary gear set with differentially meshing planets 105 are discussed in more detail herein.

[0016] The electric axle 100, in the illustrated example, is included in an electric vehicle (EV) 103. 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 electric vehicle in another example. Thus, in some examples, vehicles employing the electric axles described herein may also include an internal combustion engine (e.g., a spark-ignition engine, a compression-ignition engine, combinations thereof, and the like).The electric axles described here can be used in cars, trucks, all-terrain vehicles (ATVs), commercial vehicles, light vehicles, off-highway vehicles, mining vehicles, rail vehicles, manufacturing machinery, industrial machinery, and the like.

[0017] In the illustrated example, the mode planetary gear set 104 is further a Ravigneaux gear set. For illustrative purposes, the Ravigneaux gear set 104 includes two sets of planetary gears, one set being a simple planetary gear set and the other set being a compound planetary gear set with intermeshing planets, as in the illustrated example. However, in other examples, the Ravigneaux gear set may include a larger number of planetary gear sets. In the illustrated example, the mode planetary gear set 104 includes a first sun gear member 106 and a carrier member 108 having a set of planetary gear members 110 rotatably mounted thereon.

[0018] In the illustrated example, sun gear member 106 meshes with the planet gears of the set of planet gears 110. The mode planetary gear set 104, in the illustrated example, further includes a ring gear member 114, a set of planet gears 116, and a second sun gear member 118. In the illustrated example, the ring gear member 114 meshes with the planet gears of the set of planet gears 110. In the illustrated example, the planet gears of the second set of planet gears 116 also mesh with both the second sun gear member 118 and the gears of the set of planet gears 110. In the illustrated example, an input shaft 119 is rotatably coupled to the sun gear member 118. Various architectures for providing rotational input to the mode planetary gear set are presented herein. The set of planet gears 110 and the set of planet gears 116 are rotatably mounted on the carrier member 108.

[0019] The mode planetary gear set 104 may be specifically configured for switching between three modes. However, electric axles with a greater number of gears have also been contemplated, such as a four-gear electric axle, a five-gear electric axle, etc. To enable multi-gear functionality of the transmission, a mode clutch 120 is provided in the transmission. The mode clutch 120 is configured to lock the carrier 108 in a first mode, lock the first sun gear 106 in a second mode, and rotatably couple the carrier 108 and the first sun gear 106 in a third mode. In the illustrated example, the mode clutch 120 is in the second mode. However, the mode clutch 120 may be switched to the various modes depending on the operating conditions of the electric axle and / or the vehicle.Furthermore, the first mode has a higher gear ratio than the second mode, and the second mode has a higher gear ratio than the third mode. The specific gear ratios associated with the modes can be selected based on factors such as electric motor type and performance characteristics, vehicle weight, vehicle performance goals, and the like.

[0020] 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 aforementioned types or combinations of clutch types. Furthermore, the mode clutch 120, like the other clutches described herein, may be actuated via electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, cylinder cam actuators, combinations thereof, and the like. Shift forks, such as translatory or rotary shift forks, may be specifically used to actuate at least some of the clutches described herein.

[0021] The compound planetary gear set with differentially meshing planets 105 is rotatably coupled to the planetary gear set 104. For illustrative purposes, the ring gear 114 in the mode planetary gear set 104 is coupled via a shaft 124 and / or other suitable mechanical component to a ring gear 122 in the compound planetary gear set with differentially meshing planets 105. By mounting the compound planetary gear set with differentially meshing planets and the mode planetary gear set in this manner, a compact transmission arrangement and a desired gear ratio are achieved.

[0022] The compound planetary gear set with differentially meshing planets 105 further includes a set of planet gears 126, a set of planet gears 128, and a sun gear 130. The compound planetary gear set with differentially meshing planets 105 further includes a carrier 132 on which the planetary gear set 126 and the planetary gear set 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 132, and another output shaft 136 is coupled to the sun gear 130. The output shafts 134 and 136, in turn, are rotatably coupled to the drive gears 138 in the illustrated example. However, in other examples, the axle shafts 134 and 136 may be coupled to gear-side reductions and / or other suitable mechanical components.

[0023] At the Fig. 1A, the carrier 132 and sun gear 130 of the compound planetary gear set 105 with differentially meshing planets act as the outputs of the differential, and the sun gear 118 of the Ravigneaux gear set acts as the input of the electric axle. However, differentials with other output configurations may also be used in the electric axle, as described with respect to the Fig. 8, Fig. 10 and Fig. 11 is explained in more detail.

[0024] In the illustrated example, the mode planetary gear set 104 and the compound planetary gear set with differentially meshing planets 105 are concentric with the output rotational axis of the electric axle. This increases the compactness of the axle compared to axles with a non-concentric arrangement. A rotational axis 180 of the compound planetary gear set with differentially meshing planets 105 is Fig. 1A for reference. It should be understood that the rotational axis of the input of the mode planetary gear set 104 and the rotational axes of the axle shafts 134 and 136 are arranged coaxially with the rotational axis 180.

[0025] The use of the mode planetary gear set 104 and the compound planetary gear set with differentially meshing planets 105 can allow for the elimination of additional shafts and shift gears in the transmission (if desired), reducing the package size, narrowing the transmission width, and shortening the overall axial length, enabling a more compact and powerful electric axle design if desired. This increases transmission efficiency.

[0026] As previously explained, a relative velocity exists between the elements of the multi-gear mode planetary gear set when the mode planetary gear set 104 is operating in one of the two lower modes (i.e., the first or second mode). In the third mode, the mode planetary gear set is locked and rotates as a unit. The differential can also typically rotate as a unit and only differentiates when the vehicle is turning. The majority of the electric axle's life may be in the highest mode on certain end-use platforms, thereby reducing component wear, lowering winding losses, and increasing electric axle efficiency.

[0027] In Fig. 1A as well as in the Fig. 2A and 3A to 11, a coordinate axis system is shown for reference and, if necessary, for aligning the views. 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, for example, a longitudinal axis. However, in other examples, the axes may also have a different orientation. A rotational axis 180 of the sun gear 130 is further shown in Fig. 1A, as already indicated, for reference. The mode planetary gear set 104 and the compound planetary gear set with differentially meshing planets 105 are arranged coaxially in the illustrated example. The other electric transmissions described here also feature the coaxial arrangement between the mode planetary gear set and the differential. In this way, the electric transmission can achieve the desired space efficiency.

[0028] As in Fig. 1A, the EV 103 may further 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, random access memory, keep-alive 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, and the like described herein, as well as other variations that are foreseeable but not specifically listed.Therefore, instructions may be stored on the electronic storage medium 156 which, when executed by the processor 154, cause the control unit 152 to perform the various method steps described herein.

[0029] The controller 152 may receive various signals from sensors 158 coupled to various areas of the EV 103, and in particular, the electric axle 100. For example, the sensors 158 may include one or more engine speed sensors (discussed in more detail below), shaft / transmission 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 further provide input signals indicative of the driver's intent for vehicle control.

[0030] After receiving the signals from the various sensors 158 from Fig. 1A, controller 152 processes the received signals and deploys various vehicle component actuators 162 to adjust the components based on the received signals and instructions stored in controller 152's memory. For example, controller 152 may receive an accelerator pedal signal indicating a driver request to adjust vehicle acceleration. In response, 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 transmission 102. The other controllable components in the vehicle may function in a similar manner, for example, with respect to sensor signals, control commands, and actuator adjustment. Further, control system 150 may be employed in any of the electric axle systems and transmissions described herein.

[0031] The controller 152 may include instructions that, when executed, cause the mode clutch 120 to switch between the first mode, the second mode, and the third mode depending on the operating conditions of the vehicle and the axle. For example, the electric axle 100 may operate in the first mode when the vehicle is traveling at lower vehicle speeds. When the vehicle speed exceeds a first threshold, the mode clutch may switch to the second mode, and when the vehicle speed exceeds a second threshold, the clutch may switch from the second mode to the third mode. This switching sequence may also be implemented in reverse order through the modes. Furthermore, the switching sequence does not have to be sequential and may therefore skip modes if desired.For example, the electric axle can be instructed to start in the second mode or to downshift from the third mode to the first mode. The control system 150 described above can be used in all electric axles and transmissions described herein.

[0032] Fig. 1B shows a lever diagram 190 of the architecture of the electric axis 100 shown in Fig. 1A. The three functions of the Fig. 1A, corresponding to the first mode, the second mode, and the third mode, are indicated by devices 170, 172, and 174, respectively. However, it should be understood that the mode clutch 120 may be configured to perform the mode switching function as a clutch unit. As previously explained, in the first mode, the carrier member 108 is stationary, in the second mode, the sun gear member 106 is stationary, and in the third mode, the carrier member 108 and the sun gear member 106 are rotatably coupled. The input of the mode planetary gear set 104 is indicated by arrows 176, and the outputs of the compound planetary gear set with differentially meshing planets 105 are indicated by arrows 178 and 179. The direction of rotation of the transmission input is the same as the directions of rotation of the transmission outputs in the illustrated example. However, other designs for the transmission are also possible.

[0033] The following equations correspond to the Fig. 1A-1B. However, it should be understood that the transmission architecture may be modified to allow for other speed ratios between the components without departing from the present disclosure. Where: ωs = rotational speed of the specified sun gear ω c = rotational speed of the specified carrier ω R = rotational speed of the specified ring gear C2 = Carrier (132) R2 = ring gear (122) S2 = sun gear (130) R4=R5 = ring gear (114) P4-5 = planetary gear set (110) P5 = planetary gear set (116) S5 = sun gear (118) S4 = sun gear (106) C4=C5 = carrier (108) e2 = ratio of ring gear to sun gear R2 / S2 e4 = ratio of ring gear to sun gear R5 / S4 e5 = ratio of ring gear to sun gear R5 / S5

[0034] Speed ​​ratios in a compound planetary gear set with differentially meshing planets (w) ωC2(1−e2)=ωS2−ωR2e2

[0035] For a 1:1 differential, let ω C2 = - ω S2 if ω R2 = 0. 1−e2=ωS2ωC2=−ωS2ωS2 e2=2

[0036] Ravigneaux gear set (104) three-gear ratios (ω) ωC4(1+e4)=ωS4+ωR4e4 ωC5(1−e5)=ωS5−ωR5e5

[0037] Because: ω C4 = ω C5 (Combine Eq. 2&3) And: ω R4 = ω R5 ωR5(e4+e5)=ωS5(1+e4)−ωS4(1−e5) Mode 1 carrier 4-5 determined, ω C5 = 0 ωR5=ωS5e5 Mode 2 sun gear4 detected, ωs4 = 0 ωR5=ωS5(1+e4)(e4+e5) Mode 3 Sun gear4 locked to carrier 4-5 , ω S4 = ωC5 ωC5=ωS4=ωR4=ωR5 ωC5=ωR5=ωS5

[0038] Fig. 2A shows an example of an electric axle 200 with a transmission 201, which in turn includes a mode planetary gear set 202, a mode clutch 203, and a compound planetary gear set with differentially meshing planets 204. The compound planetary gear set with differentially meshing planets 204 in turn includes a ring gear 230, a set of planetary gears 232, a set of planetary gears 234, a sun gear 236, and a carrier 238, with the sets of planetary gears 232 and 234 rotatably mounted on the carrier 108.

[0039] The Fig. 2A illustrated compound planetary gear set with differentially meshing planets 204 and the Fig. The compound planetary gear set with differentially meshing planets 105 shown in Figure 1A have a similar design. Furthermore, the Fig. 2A and the mode clutch 203 shown in Fig. The mode clutch 120 shown in Figure 1A has a similar design. A redundant description of the structural and functional features of these components is therefore omitted for the sake of clarity.

[0040] The mode planetary gear set 202 is again depicted as a Ravigneaux gear set, which is configured to switch between three modes using the mode clutch 203. However, electric axles with a greater number of gears, such as a four-speed electric axle, have also been contemplated. Furthermore, the Ravigneaux gear set 202 includes a set of planetary gears 208 coupled to a set of planetary gears 210, and another set of planetary gears 212. The sets of planetary gears 208 and 210 are arranged as a stepped planetary arrangement. Thus, the gears of the set of planetary gears 208 mesh with a sun gear 214, and the gears of the set of planetary gears 210 mesh with a ring gear 216. The mode planetary gear set 202 further includes a set of planetary gears 212 and another sun gear 220, similar to the one shown in Fig. 1A. The gears of the set of planetary gears 212 mesh with a sun gear 220 and with a set of planetary gears 210. The sets of planetary gears 208 and 210, which form the stepped planetary gear arrangement, and the set of planetary gears 212 are rotatably coupled to a carrier 222, which can be locked by the clutch 203. However, in other examples, the Ravigneaux gear set may include a different number of planetary gear sets.

[0041] Fig. Figure 2B shows a lever diagram 290 of the electrical axis architecture used in Fig. 2A. The three functions of the Fig. 2A, corresponding to the first mode, the second mode, and the third mode, are indicated by devices 270, 272, and 274, respectively. However, it should be understood that the mode clutch 203 may be configured to perform the mode switching function as a clutch unit. As previously explained, in the first mode, the carrier member 222 is stationary, in the second mode, the sun gear member 214 is stationary, and in the third mode, the carrier member 222 and the sun gear member 214 are rotatably coupled. The input of the mode planetary gear set 202 is indicated by arrows 276, and the outputs of the compound planetary gear set with differentially meshing planets 204 are indicated by arrows 278 and 279. The direction of rotation of the transmission input is the same as the directions of rotation of the transmission outputs in the illustrated example. However, other designs for the transmission are also possible.

[0042] The following equations correspond to the Fig. 2A-2B. However, it should be understood that the transmission architecture may be modified to allow for other speed ratios between the components without departing from the present disclosure. Where: ω S = rotational speed of the specified sun gear ω C = rotational speed of the specified carrier ω R = rotational speed of the specified ring gear C2 = Carrier (238) R2 = ring gear (230) S2 = sun gear (236) R4=R5 = ring gear (216) P5a = planetary gear set (212) P5b = planetary gear set (210) P4 = planetary gear set (208) S5 = sun gear (220) S4 = sun gear (214) C4=C5 = carrier (222) e2 = ratio of ring gear to sun gear R2 / S2 e4 = ratio of ring gear to sun gear R5 / S4 e5 = ratio of ring gear to sun gear R5 / S5 N = number of teeth on the gear

[0043] Speed ​​ratios in a compound planetary gear set with differentially meshing planets (ω) ωC2(1−e2)=ωS2−ωR2e2

[0044] For a 1:1 differential, let ω C2 = - ω S2 if ω R2 = 0 1−e2=ωS2ωC2=−ωS2ωS2 e2=2

[0045] Ravigneaux gear set (202) three-speed ratios (ω) e5=NR5NS5 (Combine Eq. 3&5) ωC5=ωS5(NS5NS5−NR5)−ωR5(NR5NS5−NR5) ωP4=ωC5−NS4(ωS4−ωC5)NP4 ωP5b=ωC5+NR5(ωR5−ωC5)NP5b ωP5a=ωC5−NS5(ωS5−ωC5)NP5a ωP5a=ωC5−NP5b(ωP5b−ωC5)NP5a Because:ωP4=ωP5b (Combine Eqs. 7&8) ωC5=ωS4NS4NP5b+ωR5NP4NR5(NS4NP5b+NP4NR5) Because:ωC5=ωC5 ωR5=ωS5NS5(NS4NP5b+NP4NR5)−ωS4NS4NP5b(NS5−NR5)NR5(NS5NP4+NS4NP5b) Mode 1 carrier 4-5 determined, ω C5 = 0 ωR5=ωS5e5 Mode 2 sun gear4 detected, ω S4 = 0 ωR5=ωS5NS5(NS4NP5b+NP4NR5)NR5(NS5NP4+NS4NP5b)=ωS5(NS4NP5b+NP4NR5)e5(NS5NP4+NS4NP5b) Mode 3 Sun gear4 locked to carrier 4-5 , ω S4 = ω C5 ωC5=ωS4=ωR5=ωR4 ωC5=ωR5=ωS5

[0046] Fig. 3A shows an electric axle 300 with a transmission 302 including a Ravigneaux mode planetary gear set 304 and a compound planetary gear set with differentially meshing planets 306. The architectures of the Ravigneaux mode planetary gear set 304 and the compound planetary gear set with differentially meshing planets 306 are similar to those of the mode planetary gear set 104 and the compound planetary gear set with differentially meshing planets 105 shown in Fig. 1A. The transmission 302 in turn includes a mode clutch 308 that allows the transmission to achieve a three-speed function, similar to that shown in Fig. Gearbox 102 shown in Figure 1A.

[0047] Fig. 3A illustrates, in particular, an electric machine 310 in the electric axle 300. As described herein, the electric machines associated with the electric axles may be traction motors (e.g., motor generators). Fig. 3A is particularly arranged concentrically with the compound planetary gear set with differentially meshing planets 306 and the Ravigneaux mode planetary gear set 304. More specifically, an inner diameter 307 of a rotor 309 of the electric machine 310 is shown surrounding at least a portion of the transmission and, more particularly, the Ravigneaux mode planetary gear set 304. However, as further explained herein, the electric machine may have a variety of suitable arrangements and orientations. In the illustrated example, at least a portion of the compound planetary gear sets with meshing planets are arranged within an internal opening of the electric machine.

[0048] Fig. 3A also illustrates a differential lock clutch 312 and an axle disconnect clutch 314. The differential lock clutch 312 is configured to rotatably couple a carrier member 316 and a ring gear member 318 within the compound planetary gear set with differentially meshing planets 306. In this manner, the differential can be selectively locked to increase axle power, particularly in low-traction operating environments (e.g., all-wheel drive applications). The differential lock clutch 312 enables the output shafts 342 and 343 (e.g., axle shafts) of the compound planetary gear set with differentially meshing planets 306 to be selectively locked from rotation with each other. Furthermore, the axle disconnect clutch 314 is configured to selectively decouple the ring gear 318 in the compound planetary gear set with differentially meshing planets 306 and a ring gear 320 in the Ravigneaux mode planetary gear set 304.The axle disconnect clutch 314 allows the compound planetary gear set with differentially meshing planets 306 to be selectively decoupled from the Ravigneaux mode planetary gear set 304. The differential lock clutch 312 and / or the axle disconnect clutch 314 can be integrated into any of the transmissions described herein. The axle disconnect clutch 314 allows the efficiency of a vehicle's driveline 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.

[0049] Bearings 322 may be coupled to an input shaft 323 of the transmission 302. The input shaft 323 connects the Ravigneaux-mode planetary gear set 304 and the electric machine 310. As described herein, a bearing may include an inner race, rolling elements (e.g., cylindrical rollers, spherical balls, tapered cylindrical rollers, needle rollers, bushings, and the like), and an outer race. In the illustrated example, a bearing 324 is coupled to a sun gear member 326 in the Ravigneaux-mode planetary gear set 304. Further, a bearing 328 is coupled to a carrier member 330 in the Ravigneaux-mode planetary gear set. In the illustrated example, another bearing 332 is coupled to the carrier member 330 and the ring gear member 320. Furthermore, in the illustrated example, bearings 334 and 346 are coupled to shafts 336 and 348, respectively, and / or other suitable mechanical structures connected to gear rings 318 and 320.A bearing 338 may be coupled to the ring gear 318 and the carrier 316, a bearing 340 may be coupled to the output shaft 343 and the carrier 316, and a bearing 344 may be coupled to a carrier 316. In alternative embodiments, the bearings in the transmission may have another suitable arrangement.

[0050] Fig. 3B-3E illustrate various electrical machine and gear train arrangements for inputting the Ravigneaux mode planetary gear set 304 in various electric axle architectures. The architecture of the Ravigneaux mode planetary gear set 304, the compound planetary gear set with differentially meshing planets 306, the mode clutch 308, the differential lock clutch 312, and the axle disconnect clutch 314 in the transmission 302 is similar to that shown in Fig. 3A. For the sake of clarity, redundant description is omitted. Furthermore, it is understood that the electric machine and input gear train arrangements can be applied to electric axles in which the Ravigneaux gear set has a stepped planetary arrangement such as that shown in Fig. 2A. A redundant description of the overlapping components is therefore omitted for the sake of brevity.

[0051] Fig. 3B specifically shows an electric axle 349 having an electric machine 350 arranged concentrically with the output shaft 343 and located on an axially outer side 352 of the Ravigneaux-mode planetary gear set 304. A portion of the output shaft 343 extends through an opening in the electric machine 350 in the illustrated example. This increases the space efficiency of the electric axle. Fig. 3B further shows bearings 353 coupled to the electric machine 350. The electric axis includes additional bearings whose layout is similar to that shown in Fig. 3A. For example, rotating shafts and gears are generally coupled with bearings. The other Fig. 3C-3E also include a similar bearing layout in the Ravigneaux mode planetary gear set 304, the compound planetary gear set with differentially meshing planets 306, the axle disconnect clutch 314, and the differential lock clutch 312. However, other bearing layouts are possible, and at least one of the differential lock clutch 312 and the axle disconnect clutch 314 can be used in each of the Fig. 3A-3E may be omitted. As previously mentioned, the axle disconnect clutch 314 and the differential lock clutch 312 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. Further, the axle disconnect clutch 314 and the differential lock clutch 312 may be actuated via electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, cylinder cam actuators, combinations thereof, and the like. Shift forks, such as translatory or rotary shift forks, may be specifically used to actuate at least a portion of the clutches described herein, as previously mentioned.

[0052] Fig. 3C shows an electric axle 359 having two electric machines 360 and 362, each arranged parallel to one of the output shafts 342 and 343, and mechanically attached to the input of the transmission 302 using gear trains 363 and 367. A gear 365 meshes with gears in each of the gear trains 363 and 367 and provides a mechanical connection between a shaft 364 rotatably coupled to the input of the Ravigneaux mode planetary gear set 304. It should be 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. More generally, a variety of gear train layouts connected to the input of the Ravigneaux mode planetary gear set may be used.For example, the gear trains used to connect the first electric machine and / or the second electric machine may include additional gear passages. 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 Ravigneaux-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 Ravigneaux-mode planetary gear set. Additionally or alternatively, a planetary gear set coaxial with the rotational axis of the output shaft 343 may be used to rotatably couple the electric machine to the Ravigneaux-mode planetary gear set.In any of the embodiments where one or more planetary gear sets provide the input connection for the Ravigneaux-mode planetary gear set, a carrier member may be fixed in the planetary gear set, a ring gear member may be fixed in the planetary gear set, or a sun gear member may be fixed in the planetary gear set, in various examples. Additional gear passages, chains, belts, combinations thereof, and the like may additionally or alternatively be used to transfer mechanical power between the one or more electric machines to the Ravigneaux-mode planetary gear set.

[0053] Further, it should be understood that each of the electric axles described herein may include a second electric machine, if desired. For example, in one example, the second electric machine may be coupled to the input of the Ravigneaux mode planetary gear set in the same manner as the mechanical connection formed between the first electric machine and the input of the Ravigneaux mode planetary gear set. In another example, the second electric machine may be coupled to the input of the Ravigneaux 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, thereby allowing the second electric machine to have different characteristics than the first electric machine.Additionally, in some cases, a disconnect clutch may be arranged between the second electric machine and the Ravigneaux mode planetary gear set to decouple the second electric machine from the Ravigneaux mode planetary gear set and thus further increase efficiency.

[0054] Fig. 3D shows an electric axle 369 with electric machine 370 arranged perpendicular to the rotational axis of the transmission 302. A gear train 372 comprising bevel gears 374 serves as input to the Ravigneaux mode planetary gear set 304. Similar to the Fig. For the exemplary electric axle 359 shown in Figure 3C, the addition of a second electric machine and a second disconnect clutch for the electric machine was considered. Furthermore, bevel gears 387 are provided in gear train 372 to connect the gear train to input shaft 388.

[0055] Fig. 3E shows an electric axle 379 with an electric machine 380 arranged perpendicular to the rotational axis of the transmission 302. In the illustrated example, the electric axle includes an input gear train 382 with multiple reduction ratios 383 and 384 that are selectable via a clutch 385. In this way, the selectable gearing in the transmission can be further expanded, which can enable more efficient operation of the electric machine. Similar to the Fig. For the exemplary electric axle 359 shown in Figure 3C, the addition of a second electric machine and a second electric machine disconnect clutch was considered. However, as previously mentioned, a variety of gear train layouts were considered that provide an input for the Ravigneaux mode planetary gear set.

[0056] It is understood that electric axles that combine features of input gear train and / or motor arrangement from two or more of the Fig. 3A-3E. Furthermore, any of the various motor and / or input gear train arrangements may be used with any of the transmission architectures or combinations of transmission architectures described herein.

[0057] Fig. 4 shows another example of a transmission 400 for an electric axle. The transmission 400, in the illustrated example, again includes a compound planetary gear set with differentially meshing planets 404, a Ravigneaux mode planetary gear set 406, and a mode clutch 408. The arrangement of the compound planetary gear set with differentially meshing planets 404 and the Ravigneaux mode planetary gear set 406 is identical to that of the compound planetary gear set with differentially meshing planets 105 and the mode planetary gear set 104 shown in Fig. 1A. A redundant description of the overlapping components is therefore omitted for the sake of brevity.

[0058] As in Fig. 4, a simple planetary gear set 410 is further coupled via a carrier 413 directly to a sun gear 412 in the Ravigneaux mode planetary gear set 406. Furthermore, a sun gear 414 of the simple planetary gear set acts as the input of the transmission. Furthermore, in the Fig. 4, a ring gear 418 is fixed in the simple planetary gear set. However, other simple planetary gear set configurations are also possible. For example, in the simple planetary gear set 410, the ring gear 418 may be coupled to the sun gear 412 in the Ravigneaux mode planetary gear set 406, and in the simple planetary gear set 410, the carrier gear 413 may be fixed, and the sun gear 414 of the simple planetary gear set 410 may function as the input of the transmission.

[0059] Fig. 5 shows another example of a transmission 500 for an electric axle. The transmission 500, in the illustrated example, includes a compound planetary gear set with differentially meshing planets 502, a Ravigneaux mode planetary gear set 504, and a mode clutch 506, similar to the one shown in Fig. 1A shown gear 102. As in Fig. 5, a compound planetary gear set with meshing planets 508 is further coupled via a carrier 511 directly to a sun gear 510 in the Ravigneaux mode planetary gear set 504. A sun gear 512 of the compound planetary gear set with meshing planets 508 acts as the input of the transmission 500. Furthermore, in Fig. 5, a ring gear 514 is fixed in the compound intermeshing planetary gear set 508. However, other configurations of compound intermeshing planetary gear sets are also possible. For example, in the compound intermeshing planetary gear set 508, the ring gear 514 may be coupled to the sun gear 510 in the Ravigneaux mode planetary gear set 504, and in the compound intermeshing planetary gear set 508, the carrier 511 may be fixed, and the sun gear 512 of the compound intermeshing planetary gear set 508 may function as the input of the transmission.

[0060] Fig. 6 shows another example of a transmission 600 for an electric axle. The transmission 600, in the illustrated example, again includes a compound planetary gear set with differentially meshing planets 602 and a Ravigneaux mode planetary gear set 604 with a mode clutch 605. However, in the illustrated example, a single planetary gear set 606 is arranged between the compound planetary gear set with differentially meshing planets 602 and the Ravigneaux mode planetary gear set 604. For explanation, in the illustrated example, a sun gear 608 in the simple planetary gear set 606 is rotatably coupled to a ring gear 610 in the Ravigneaux mode planetary gear set 604, a carrier 611 in the simple planetary gear set 606 is rotatably coupled to a ring gear 612 in the compound planetary gear set with differentially meshing planets 602, and a ring gear 614 in the simple planetary gear set 606 is fixed.However, other planetary gear set configurations are also possible. For example, in the single planetary gear set 606, the ring gear 614 may be coupled to the ring gear 612 in the compound planetary gear set with differentially meshing planets 602. In the single planetary gear set 606, the carrier gear 611 may be fixed, and the sun gear 608 in the single planetary gear set 606 may be rotatably coupled to a ring gear 610 in the Ravigneaux mode planetary gear set 604.

[0061] Fig. 7 shows another example of a transmission 700 for an electric axle. The transmission 700, in the illustrated example, again includes a compound planetary gear set with differentially meshing planets 702 and a Ravigneaux mode planetary gear set 704 with a mode clutch 705. The transmission further includes another compound planetary gear set with meshing planets 706 with a carrier 708 rotatably coupled to a ring gear member 710 of the compound planetary gear set with differentially meshing planets 702. The compound planetary gear set with meshing planets 706 further includes a sun gear member 712 rotatably coupled to a ring gear member 714 in the Ravigneaux mode planetary gear set 704. Additionally, in the illustrated example, a ring gear member 716 is fixed in the compound planetary gear set with meshing planets 706. However, as previously mentioned, other planetary gear set configurations are possible.For example, in the compound meshing planetary gear set 706, the ring gear 716 may be coupled to the ring gear 710 in the compound differentially meshing planetary gear set 702, and in the compound meshing planetary gear set 706, the carrier member 708 may be fixed, and the sun gear 712 in the compound meshing planetary gear set 706 may be rotatably coupled to a ring gear 714 in the Ravigneaux mode planetary gear set 704. It should be understood that the configurations shown in . Fig. 4-7 as well as the other transmissions described here may include axle disconnect clutches and / or differential lock clutches.

[0062] Fig. 8 shows another example of a transmission 800 for an electric axle. In the illustrated example, the transmission 800 includes a Ravigneaux-mode planetary gear set 802. However, in the illustrated example, a ring gear 803 within the Ravigneaux-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 using a clutch, friction, preload ratios, and / or other suitable devices and methods.

[0063] Fig. 9 shows another example of a transmission 900 for an electric axle. The transmission 900, in the illustrated example, again includes a compound planetary gear set with differentially meshing planets 902. The transmission 900 also includes a Ravigneaux mode planetary gear set 904 with a different architecture than the previously described Ravigneaux mode planetary gear sets. For illustrative purposes, the Ravigneaux mode planetary gear set 904 includes a carrier 906 rotatably coupled to a ring gear member 908 of the compound planetary gear set with differentially meshing planets 902. Furthermore, a sun gear member 910 in the Ravigneaux mode planetary gear set 904, which meshes with a set of planet gears 912, functions as the input of the Ravigneaux mode planetary gear set 904.Furthermore, a mode clutch 914 is configured to lock the ring gear 920 meshing with the planet gears 912 in a first mode, lock the sun gear 916 meshing with the planet gears 918 in a second mode, and rotatably couple the ring gear 920 and the sun gear 916 in a third mode. In the illustrated example, the planet gears 918 mesh with the planet gears 912. The set of planet gears 918 and the set of planet gears 912 are rotatably mounted on the carrier 906. In this manner, the input and output of the Ravigneaux mode planetary gear set can be varied. However, other planetary gear set configurations are possible, including arrangements in which the planet gears 912 comprise a stepped planetary arrangement.

[0064] Fig. 10 shows another example of a transmission 1000 for an electric axle. The transmission 1000 again includes a Ravigneaux mode planetary gear set 1002 in the illustrated example. However, in the illustrated example, a ring gear 1003 in the Ravigneaux mode planetary gear set 1002 is rotatably coupled to a carrier 1006 in a dual sun differential 1008. The dual sun differential 1008 further includes a first sun gear 1010 and a second sun gear 1012 coupled to output shafts 1014 and 1018, respectively. Planet gears 1004 mesh with planet gears 1016 and sun gear 1010, and planet gears 1016 mesh with sun gear 1012. The planet gears 1004 and 1016 are rotatably mounted on the carrier 1006 in the illustrated example.The dual sun differential may be an open differential or a limited-slip differential configured to limit the speed differentiation between the output shafts 1014 and 1018 using a clutch, friction, preload ratios, and / or other suitable devices and methods. It is understood that the Ravigneaux mode planetary gear sets described herein may be coupled with other types of differentials, such as limited-slip differentials, open differentials, and the like.

[0065] Fig. 11 shows another example of a transmission 1100 for an electric axle. The transmission 1100 again includes a Ravigneaux mode planetary gear set 1102 with a mode clutch 1104. The transmission 1100 further includes an open differential 1106 with a differential carrier 1108 driven by a ring gear 1110 in the Ravigneaux mode planetary gear set 1102. The differential 1106 further includes differential pinion gears 1120 (which may be referred to as spider 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 the output shafts 1114 and 1116. It is further understood that the Fig. 11) differential 1106 as well as the one shown in Fig. 8 and Fig. 10 differentials shown are examples of double sun gear differentials.

[0066] Furthermore, it is understood that the Fig. 1A-11 can be 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 (LSD) (e.g., a torque sensing limited slip differential), an automatic torque biasing (ATB) limited slip differential, a clutch pack style limited slip differential, a bevel gear differential, a dual sun differential, a gear ratio differential, and the like.

[0067] The output shafts in the electric axles described herein can be directly coupled to drive wheels, wheel-side reductions (e.g., planetary reductions in the wheel hubs), or other suitable mechanical components in applications requiring a differential output in vehicles (e.g., cars, trucks, boats, ATVs, 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 electric vehicles (BEVs)) and hybrid electric vehicles.Thus, in some examples, vehicles employing the transmissions described herein may include an internal combustion engine (e.g., a spark-ignition engine, a compression-ignition engine, combinations thereof, and the like). Furthermore, the electric axles described herein may include axle disconnect and / or differential locking features.

[0068] The gearing in the planetary gear sets described herein may have a straight or helical tooth profile. As described above, the second motors in the electric axles described herein are optional. Further, in one example, the gearing used to mechanically couple the motors to the transmission input may be identical and mesh with a last 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 last gear on the output centerline. Further, in one example, the gearing associated with the second motor may include a clutch to decouple the second electric machine from the mode planetary gear set to further increase efficiency in some cases.

[0069] Further, in one example, the gearing associated with the second motor may mesh with the gearing associated with the first motor before the last gear on the output centerline. Furthermore, in one example, the gearing associated with the second motor may have a different ratio and mesh with the gearing associated with the first motor before the last gear on the output centerline.

[0070] Furthermore, in an application example, the Fig. 1A-11 have a gear ratio of 1:1 in one of the modes. However, the electric axle can have a variety of ratios that can be selected depending on the end-use design goals of the vehicle platform. Thus, the gear ratios shown in the Fig. The ratios illustrated in Figure 1A-11 are use case ratios, and other ratios may be used in the electrical axes.

[0071] Furthermore, the exact location and number of camps in the Fig. 3A-3E are illustrative and exemplary, and it is understood that alternative bearing layouts, types, quantities, etc. may be used in alternative examples.

[0072] Further, it is understood that the electric axles may utilize one or more transverse motors coupled to the transmission input via hypoid gears or other suitable spiral or bevel gears. In such an example, the motor may mesh with the hypoid gear using a mating pinion gear, and additional gear passages and / or shiftable gears may be present between the motor and the pinion gear. In various examples, the shiftable gears may be located on each parallel partner shaft. Further, additional gear passages may be added to the electric axles, if desired. Still further, 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.

[0073] Furthermore, it is understood that the various Fig. 3A-3E can be used in any of the electric axes described herein, such as in any of the Fig. 1A, 2A, and 4-11, or in combinations of the aforementioned electric axes. Furthermore, various combinations of the motor architectures and transmission architectures were envisioned, incorporating multiple features from various embodiments.

[0074] The invention is described in more detail in the following sections. In one aspect, an electric axle system is provided comprising: an electric machine; a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts, and comprising: a Ravigneaux gear set rotatably coupled to and coaxial with a differential; and a mode clutch configured to selectively: lock a carrier or a ring gear in the Ravigneaux gear set; lock a sun gear in the Ravigneaux gear set; and rotatably couple the carrier or the ring gear to the sun gear in the Ravigneaux gear set. In one example, the differential may be a compound planetary gear set having differentially meshing planets.In another example, a ring gear in the Ravigneaux gear set may be rotatably coupled to a ring gear in the compound planetary gear set with differentially meshing planets. 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. In another example, the electric axle system may further include an axle disconnect clutch configured to selectively disconnect the Ravigneaux gear set from the differential. Further, in one example, the differential may be a dual sun gear planetary gear set. In another example, the electric machine may be arranged coaxially, parallel, or transversely to the Ravigneaux gear set and the differential.In another example, the electric axle system may further include a second electric machine rotatably coupled to the multi-speed transmission. In another example, the Ravigneaux gear set and the differential are disposed at least partially within an inner diameter of a rotor of the electric machine. In another example, the electric axle may further include a third planetary gear set rotatably coupled to an input of the Ravigneaux gear set or rotatably coupled to an input of the differential and an output of the Ravigneaux gear set.

[0075] In another aspect, a method of operating an electric axle system is provided, comprising operating a mode clutch to: in a first mode, lock a carrier or ring gear in a Ravigneaux gear set; in a second mode, lock a sun gear in the Ravigneaux gear set; and in a third mode, rotatably couple the carrier or ring gear to the sun gear in the Ravigneaux gear set; wherein the electric axle system comprises: an electric machine; a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts, and including: the Ravigneaux gear set rotatably coupled to and coaxial with a differential; and the mode clutch.In one example, the differential may be a compound planetary gear set with differentially meshing planets; a ring gear in the Ravigneaux gear set may be rotatably coupled to a ring gear in the compound planetary gear set with differentially meshing planets; and a sun gear and a carrier gear in the compound planetary gear set with differentially meshing planets may be rotatably coupled to separate output shafts. In one example, the method may further include 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 another example, the method may further include operating an axle disconnect clutch to selectively disconnect the Ravigneaux gear set from the differential.

[0076] In another aspect, an electric axle system is provided that includes an electric machine; a multi-speed transmission rotatably coupled to the electric machine and comprising: a Ravigneaux gear set rotatably coupled to and coaxial with a compound planetary gear set having differentially meshing planets; and a mode clutch configured to switch the Ravigneaux gear set between three modes; wherein the compound planetary gear set having differentially meshing planets is rotatably coupled to two output shafts. In one example, the mode clutch may be configured: in a first mode, to lock a carrier or a ring gear in the Ravigneaux gear set; in a second mode, to lock a sun gear in the Ravigneaux gear set; and in a third mode, to rotatably couple the carrier or the ring gear to the sun gear in the Ravigneaux gear set. In one example, the electric axle system may further include a differential lock clutch configured to selectively rotatably couple a ring gear in the compound planetary gear set with differentially meshing planets to a carrier in the compound planetary gear set with differentially meshing planets to lock rotation of the two output shafts; and an axle disconnect clutch configured to selectively disconnect the Ravigneaux gear set from the compound planetary gear set with differentially meshing planets.In one example, in the system, a ring gear member in the Ravigneaux gear set may be rotatably coupled to a ring gear member in the compound planetary gear set with differentially meshing planets; and a sun gear member in the compound planetary gear set with differentially meshing planets may be rotatably coupled to a first axle shaft; and the carrier member in the compound planetary gear set with differentially meshing planets may be rotatably coupled to a second axle shaft. Furthermore, in one example, the electric axle system may further include a second compound planetary gear set with differentially meshing planets rotatably coupled to the Ravigneaux gear set and the compound planetary gear set with differentially meshing planets. In another example, a ring gear member in the compound planetary gear set with differentially meshing planets may be rotatably coupled to a carrier member or a ring gear member in the Ravigneaux gear set.

[0077] Fig. 1A-11 show example configurations with relative arrangement of the various components. When these elements are shown in direct contact with one another or directly coupled, they may be referred to as directly contacting or directly coupled, respectively, at least in one example. Likewise, elements shown as adjacent or juxtaposed may each be adjacent or adjacent to one another, at least in 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, elements that are separated from one another only by a space and without any other components may be referred to as such, at least in one example. As another example, elements shown above / below, on opposite sides of, or to the left / right of each other may be referred to as such, relative to one another.Furthermore, as shown in the figures, a topmost element or a topmost point of the element may be referred to as the "top" of the component, and a bottommost element or a bottommost point of the element may be referred to as the "bottom" of the component, at least in one example. The terms top / bottom, upper / lower, over / under, as used herein, may refer to a vertical axis of the figures and may be used to describe the arrangement of elements of the figures relative to one another. Thus, in one example, elements shown above other elements are arranged vertically above the other elements. As another 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). Additionally, in one example, elements that are coaxial with one another may be referred to as such.Furthermore, in at least one example, elements shown intersecting one another may be referred to as intersecting elements or intersecting elements. Furthermore, in one example, an element shown inside another element or outside another element may be referred to as such. In other examples, elements offset from one another may be referred to as such.

[0078] Motor and shift control logic / programs, inverters, electronic control units (ECUs), memory, throttle, brake, speed and incline sensors and the like, shift actuators, etc. may also be used in any electric axles and transmissions described herein.

[0079] Fig.1A-11 illustrate a method for operating an electric axle, wherein the transmission switches between two of the three modes depending on the vehicle's operating conditions. The method may further selectively lock the differential by operating a differential lock clutch in the differential. The method may further include selectively disconnecting the axle by operating an axle disconnect clutch.

[0080] 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 that includes the controller in combination with the various sensors and actuators. Further, 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 of any number of processing strategies, such as event-driven, interrupt-driven, multitasking, multithreading, and the like.Thus, various illustrated actions, operations, and / or functions may be performed in the illustrated order, in parallel, or in some cases not at all. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the examples described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations, and / or functions may be performed repeatedly depending on the strategy used. Further, 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 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 control unit.One or more of the process steps described here may be omitted if desired.

[0081] Although various embodiments have been described above, it is understood that they have been presented only as examples and not as restrictions or limitations. It is understood that the configurations and routines disclosed herein are exemplary in nature, and that these specific examples are not to be interpreted in a limiting sense, as numerous variations are possible. For example, the above technology 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 powertrain systems not applicable to, for example, machines and drive systems for tandem axles, electric tag axles, P4 axles, EVs (e.g., HEVs, BEVs, etc.).), agricultural vehicles or machines, marine vehicles or machines, motorcycles, recreational vehicles, on- and off-highway vehicles, mining vehicles, rail vehicles, production machines, industrial machines, and the like. 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. It will be apparent to those skilled in the art that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter.

[0082] The following claims particularly point out certain combinations and subcombinations that are considered unique and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims should be understood to encompass 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, the same as, or different from the original claims, are also considered to be 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 / 515,760

[0001] Cited non-patent literature

[0000] Electric AXLE”, which took place on July 26, 2023

[0001]

Claims

[1] Electric axle system comprising: an electrical machine; a multi-speed transmission rotatably coupled to the electric machine, rotatably coupled to two output shafts and comprising: a Ravigneaux gear set rotatably coupled to and coaxial with a differential; and a mode clutch that is set up, optionally: to detect a carrier or a ring gear in the Ravigneaux gear set; to locate a sun gear in the Ravigneaux gear set; and to rotatably couple the carrier or the ring gear to the sun gear in the Ravigneaux gear set. [2] The electric axle system of claim 1, wherein the differential is a compound planetary gear set having intermeshing planets. [3] The electric axle system of claim 2, wherein a ring gear in the Ravigneaux gear set is rotatably coupled to a ring gear in the compound planetary gear set with differentially meshing planets. [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 1, further comprising an axle disconnect clutch configured to selectively disconnect the Ravigneaux gear set from the differential. [6] The electric axle system of claim 1, wherein the differential is a double sun gear planetary gear set. [7] Electric axle system according to claim 1, wherein the electric machine is arranged coaxially, parallel or transversely to the Ravigneaux gear set and the differential. [8] The electric axle system of claim 1, further comprising a second electric machine rotatably coupled to the multi-speed transmission. [9] The electric axle system of claim 1, wherein the Ravigneaux gear set and the differential are at least partially disposed within an inner diameter of a rotor of the electric machine. [10] The electric axle system of claim 1, further comprising a third planetary gear set rotatably coupled to an input of the Ravigneaux gear set or rotatably coupled to an input of the differential and an output of the Ravigneaux gear set. [11] An electric axle system according to claim 1, wherein the mode clutch is configured: in a first mode, to detect a carrier or a ring gear in the Ravigneaux gear set; in a second mode, to fix a sun gear in the Ravigneaux gear set; and In a third mode, the carrier or the ring gear is rotatably coupled to the sun gear in the Ravigneaux gear set. [12] The electric axis system of claim 1, further comprising: a differential lock clutch configured to selectively rotatably couple a ring gear in the compound planetary gear set with differentially meshing planets to a carrier in the compound planetary gear set with differentially meshing planets to lock rotation of the two output shafts; and a separating clutch designed to selectively separate the Ravigneaux gear set from the compound planetary gear set with differentially meshing planets. [13] An electric axle system according to claim 1, wherein: a ring gear in the Ravigneaux gear set is rotatably coupled to a ring gear in the compound planetary gear set with differentially meshing planets; and a sun gear in the differentially meshing compound planetary gear set is rotatably coupled to a first output shaft; and the carrier in the compound planetary gear set with differentially meshing planets is rotatably coupled to a second output shaft. [14] The electric axle system of claim 13, further comprising a second compound planetary gear set with differentially meshing planets rotatably coupled to the Ravigneaux gear set and the compound planetary gear set with differentially meshing planets. [15] The electric axle system of claim 14, wherein a ring gear in the compound planetary gear set with differentially meshing planets is rotatably coupled to a carrier or a ring gear in the Ravigneaux gear set.

Images