Electric axle system

Abstract

The utility model relates to an electric axle system. In one example, an electric axle system includes an electric machine, a multi-speed transmission rotationally coupled to the electric machine, a multi-speed transmission rotationally coupled to two output shafts, and a Ravigneaux gear set rotationally coupled and positioned coaxially with a differential. The electric axle system also includes a mode clutch configured to selectively engage the carrier or ring gear in the Ravigneaux gear set, engage the sun gear in the Ravigneaux gear set, and couple the carrier or ring gear in the Ravigneaux gear set with the sun gear.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] 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 application are incorporated herein by reference. Technical Field

[0003] This description generally relates to an electric axle with two concentric planetary gear sets. Background Art

[0004] E-axles are being adopted across various vehicle platforms to address electrification needs in diverse vehicle segments. These e-axles consist of a traction motor and transmission, which can be installed in various configurations depending on the vehicle platform's space constraints and intended end-use. Compared to electric drives that design the traction motor, transmission, and drive axle as separate units, e-axles offer simplified and more efficient vehicle platform integration.

[0005] At least some e-axles have failed to achieve their end-use design goals in terms of space efficiency, shifting functionality, and power density. For example, some multi-speed transmissions use a large number of parallel shafts and gears, which creates packaging challenges. Furthermore, in previous multi-speed transmissions, all gears are engaged, but in certain modes, torque is transmitted through only some gears, while others are unloaded. Consequently, unloaded gears result in unavoidable axle, meshing, and airflow losses. Therefore, the inventors recognized the desire to reduce packaging space and increase the power density of e-axles. Utility Model Content

[0006] An electric axle system can address these issues. In one example, the system includes an electric motor and a multi-speed transmission rotationally coupled to the motor and to two output shafts. The multi-speed transmission includes a Ravigneaux gear set rotationally coupled and positioned coaxially with a differential. The multi-speed transmission also includes a mode clutch that shifts the multi-speed transmission between a first mode, a second mode, and a third mode. In this way, the Ravigneaux gear set efficiently implements three gear ratio modes in a space-saving package, thereby expanding the system's speed-shifting capabilities.

[0007] In one example, the differential is a differential meshing compound planetary gear set. This allows for a space-efficient electric axle with the desired power density. More specifically, using a differential meshing compound planetary gear set and a Ravigneaux gear set in this configuration allows the electric axle to forgo the use of additional shafts (e.g., a paved axle with an idler gear) if required, while achieving the desired number of gear modes and ratios. This increases customer appeal.

[0008] In one example, the e-axle system also includes a differential locking clutch configured to selectively couple the second ring gear of the differential to the differential carrier, thereby locking the rotation of both output shafts. Furthermore, in one example, the e-axle also includes an axle disconnect clutch configured to selectively disconnect the Ravigneaux gear set from the differential. This expands the functionality of the e-axle to include differential locking and axle disconnect capabilities, further enhancing its appeal to customers.

[0009] It should be understood that the above summary is intended to introduce concepts further described in the detailed description in a simplified form. It is not intended to identify key or essential features of the claimed subject matter, the scope of which is determined solely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figures 1A-1B An example of an electric axle with a compound planetary gear set with differential meshing planets, a Ravigneaux gear set consisting of two sets of planetary gears (one of which is a simple planetary gear), and a mode clutch is shown.

[0011] Figures 2A-2B An example of an electric axle is shown with a compound planetary gear set with differential meshing planets, a Lavigne-Herxes gear set with two sets of planetary gears (one set being stepped planets), and a mode clutch.

[0012] Figures 3A-3E Shows the Figures 1A-1B Different examples of electric motor and input gear train structures for electric axles described in.

[0013] Figure 4-7 Various examples of transmissions for electric axles are shown having a differentially meshing planetary compound gear set and a Ravigneaux gear set rotationally coupled to another planetary gear set in a different configuration.

[0014] Figure 8 Another example of an electric axle with a Lavignere gear set and limited-slip differential is shown.

[0015] Figure 9 Another example of an electrically variable transmission with a multi-speed Ravigneaux gear set and a differential meshing planetary compound planetary gear set is shown.

[0016] Figure 10 Another example of an electric axle with a Lavignere gear set and a double sun gear differential is shown.

[0017] Figure 11 Another example of an electric axle with a Lavignere gear set and open differential is shown. DETAILED DESCRIPTION

[0018] This article describes a differentiated multi-speed e-axle with mode selection, achieving greater compactness and power density. Previous multi-speed e-axles used multiple parallel shafts, which posed packaging challenges. For example, some multi-speed e-axles utilize at least two shafts dedicated to gear shifting. In these e-axles, all gears are meshed, but in certain modes, torque is transmitted through only some gears, while others are unloaded. Consequently, unloaded gears result in unavoidable axle, meshing, and airflow losses. Furthermore, the relatively wide differentials using spider gears may present axial packaging challenges in some vehicles, limiting the differential's applicability. Certain planetary gear differentials, such as compound planetary gear differentials with two output sun gears or two output ring gears, two concentric simple planetary gear sets placed side by side, and two nested concentric planetary gear sets, may also pose challenges with the drive axle's axial length and / or overall diameter. However, these types of planetary gear sets can be used in any of the e-axles described herein.

[0019] As used herein, a simple planetary gear set is a planetary gear set that has only a ring gear, a sun gear, a carrier, and multiple planet gears that are coplanar with the ring and sun gears and rotate on the carrier. Each planet gear meshes with both the sun and ring gears. Furthermore, as used herein, a meshing planet compound planetary gear set is a planetary gear set that has a ring gear, a sun gear, and multiple sets of planet gears that mesh within the plane of the ring and sun gears and are circumferentially aligned in the same plane as the ring and sun gears. A planetary gear set includes inner planet gears and outer planet gears. The inner planet gears mesh with both the sun gear and the outer planet gears. The outer planet gears mesh with both the inner planet gears and the ring gear.

[0020] To achieve space efficiency and power density goals, one example electric axle includes a transmission featuring a multi-speed mode-select planetary gearset and a compact planetary differential in a coaxial package. Specifically, the multi-speed gearset in the transmission includes a Ravigneaux gearset with a mode clutch for shifting between gear modes. Furthermore, the differential planetary gearset in the transmission is a compound planetary gearset with meshing planets.

[0021] In one example, an electric axle includes a differential and a multi-speed planetary gearset concentric with the electric axle output shaft. Furthermore, the differential in the electric axle can be comprised of a compound planetary gearset with meshing planetary gears. Using a mode and differential planetary gearset can eliminate multiple shafts in the system for gear shifting, if desired. This improves packaging efficiency, reduces the width of the differential, and reduces the overall axial length of the electric axle as needed, resulting in a more compact and power-dense electric axle structure. Unlike previous multi-speed electric axles, all gears in a multi-speed electric axle can transmit torque. Specifically, in adjacent speed mode, there can be no idle gears in the system, eliminating axle, meshing, and airflow losses. Consequently, transmission efficiency is improved.

[0022] When a multi-speed (e.g., three-speed) e-axle is in one of its two lower modes (e.g., first or second), relative speeds exist between the elements of the modal planetary gearsets. In the third mode, the modal planetary gearsets can be locked and rotate as a single unit. The differential planetary gearsets can also rotate as a single unit, with differential speeds being applied only when the vehicle is turning. In practice, a transmission may spend more (e.g., most) of its life in the highest mode than in the other modes. In the highest mode, the planetary gearsets rotate as a single unit. Because there are no relative rotations within the differential planetary gearsets and no relative rotation within the multi-speed planetary gearsets, gear meshing noise is reduced, tooth wear is reduced, component life is extended, friction losses are reduced, and windage losses are reduced, thereby improving overall axle efficiency. With increased lifespan and a larger array of planetary gear pairs, there is an opportunity to reduce the width of the differential and modal planetary gearsets, thereby reducing the axial length of the e-axle as needed. Additionally, in certain end-use operating scenarios, the e-axle may operate in the highest mode longer than in other modes, and the meshing planetary gear pairs have no relative speed, so there is an opportunity to use spur gears in the planetary gear sets, thereby further reducing the cost and complexity of the e-axle and simplifying the component manufacturing of the differential planetary gear sets and multi-speed mode planetary gear sets.

[0023] The layout of the differentiated multi-speed electric axle described herein allows for the easy and efficient integration of axle disconnect and differential locks when required. Consequently, the electric axle can implement additional functionality that is difficult to achieve with other axle configurations, such as parallel-axle differential designs. Furthermore, it will be appreciated that the electric axle described herein can be designed with the motor positioned concentrically with the output shaft, coaxially with the output shaft, parallel to the output shaft, at a 90-degree angle, or at any other suitable angle relative to the output shaft.

[0024] Figure 1AAn example of an electric axle 100 is shown with a transmission 102 that includes a modal planetary gear set 104. In the illustrated example, the electric axle 100 also includes a differential meshing planetary compound gear set 105. The modal planetary gear set 104 and the differential meshing planetary compound gear set 105 will be discussed in detail herein.

[0025] In the illustrated example, the electric axle 100 is included in an electric vehicle (EV) 103. It will be appreciated that the other electric axles described herein may also be included in similar electric vehicles. The electric vehicle 103 may be an all-electric vehicle (e.g., a battery electric vehicle (BEV)) in one example and a hybrid electric vehicle in another example. Thus, in some examples, a vehicle utilizing the electric axles described herein may also have an internal combustion engine (e.g., a spark-ignition engine, a compression-ignition engine, a combination thereof, etc.). Thus, the electric axles described herein may be used in automobiles, trucks, all-terrain vehicles (ATVs), commercial vehicles, light vehicles, off-highway vehicles, mining vehicles, rail vehicles, manufacturing machinery, industrial machinery, and the like.

[0026] Furthermore, in the illustrated example, the modal planetary gear set 104 is a Ravigneaux gear set. Specifically, the Ravigneaux gear set 104 includes two sets of planetary gears, one of which is a simple planetary gear set and the other is a compound planetary gear set with meshing planets. However, in other examples, the Ravigneaux gear set may include more planetary gear sets. Specifically, in the illustrated example, the modal planetary gear set 104 includes a first sun gear 106 and a carrier 108 on which a set of planetary gears 110 are rotatably mounted.

[0027] In the illustrated example, sun gear 106 meshes with the planet gears in planetary gear set 110. In the illustrated example, modal planetary gear set 104 also includes a ring gear 114, a set of planet gears 116, and a second sun gear 118. Furthermore, in the illustrated example, ring gear 114 meshes with the planet gears in planetary gear set 110. In the illustrated example, the planet gears in the second set of planet gears 116 mesh with sun gear 118 and the gears in planet gear set 110. In the illustrated example, input shaft 119 is rotationally coupled to sun gear 118. Various structures that provide rotational input to the modal planetary gear set will be described in detail herein. Planetary gear set 110 and planet gears 116 are rotatably mounted on carrier 108.

[0028] The mode planetary gear set 104 can be specifically configured to switch between three modes. However, we have also considered electric axles with more speeds, such as four-speed electric axles, five-speed electric axles, etc. In order to realize the multi-speed function of the transmission, a mode clutch 120 is provided in the transmission. The mode clutch 120 is configured to fix the carrier 108 in the first mode, fix the first sun gear 106 in the second mode, and rotationally couple the carrier 108 and the first sun gear 106 in the third mode. In the illustrated example, the mode clutch 120 is in the second mode. However, the mode clutch 120 can be switched to different modes depending on the operating conditions of the electric axle and / or the vehicle. In addition, the gear ratio of the first mode is higher than that of the second mode, and the gear ratio of the second mode is higher than that of the third mode. The specific gear ratio associated with the mode can be selected based on factors such as the type and performance characteristics of the electric motor, the weight of the vehicle, and the performance goals of the vehicle.

[0029] The mode clutch 120 can be a dog clutch, a synchronizer, a friction clutch (e.g., a wet friction clutch), a radial clutch, a face clutch, a crank clutch, a magnetic clutch, and combinations thereof. Other clutches described herein can also be any of the above-mentioned types of clutches or combinations of clutch types. In addition, the mode clutch 120 and other clutches described herein can be actuated by electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, barrel cam actuators, combinations thereof, etc. A shift fork, such as a translational or rotary shift fork, can be specifically used to drive at least a portion of the clutches described herein.

[0030] The differential meshing planetary compound gear set 105 is rotationally coupled to the pattern planetary gear set 104. Specifically, the ring gear 114 in the pattern planetary gear set 104 is connected to the ring gear 122 in the differential meshing planetary compound gear set 105 via a shaft 124 and / or other suitable mechanical components. Connecting the differential meshing planetary compound gear set and the pattern planetary gear set in this manner allows the transmission to achieve a compact layout and a desired gear ratio.

[0031] The differential-meshing planetary compound gear set 105 also includes a set of planetary gears 126, a set of planetary gears 128, and a sun gear 130. The differential-meshing planetary compound gear set 105 also includes a carrier 132 on which the set of planetary gears 126 and the set of planetary gears 128 are rotatably fixed. In the illustrated example, an output shaft 134 (e.g., a half shaft, etc.) is connected to the carrier 132, and another output shaft 136 is connected to the sun gear 130. In the illustrated example, the output shafts 134 and 136 are in turn rotationally coupled to drive wheels 138. However, in other examples, the output shafts 134 and 136 may be connected to a wheel-end gear reducer and / or other suitable mechanical components.

[0032] exist Figure 1A In the illustrated electric axle 100, the carrier 132 and sun gear 130 of the differential meshing planetary compound gear set 105 serve as the output of the differential, while the sun gear 118 of the Ravigneaux gear set serves as the input of the electric axle. Figure 8 、 Figure 10 and Figure 11 As mentioned above, electric axles can use differentials with different output configurations.

[0033] In the example shown, the mode planetary gear set 104 and the differential meshing planetary compound gear set 105 are concentric with the output rotation shaft of the electric axle. In this way, the structure of the axle is more compact than that of an axle with a non-concentric arrangement. Figure 1A The rotation axis 180 of the differential meshing planetary compound gear set 105 is provided for reference. It is understood that the rotation axis of the input end of the mode planetary gear set 104 and the rotation axes of the output shafts 134 and 136 are coaxially arranged with the rotation axis 180.

[0034] The use of the mode planetary gear set 104 and the differential meshing planetary compound planetary gear set 105 can eliminate additional shafts and shift gears (if necessary) in the transmission, reduce packaging, reduce transmission width, and reduce overall axial length, thereby enabling the design of a more compact and power-dense electric axle as required. In this way, the efficiency of the transmission is improved.

[0035] As described above, when the modal planetary gear set 104 operates in one of the two lower modes (i.e., the first mode or the second mode), relative speeds exist between the elements of the multi-speed modal planetary gear set. In the third mode, the modal planetary gear set is locked and rotates as a unit. The differential also typically rotates as a unit and independently performs differential speeds when the vehicle turns. In certain end-use platforms, the e-axle may spend most of its life in the highest mode, thereby reducing component wear, lowering windage losses, and improving e-axle efficiency.

[0036] Figure 1A as well as Figure 2A-11 A coordinate axis system is provided for reference and, when appropriate, orientation of a view. In one example, the Z axis can be the vertical axis (e.g., parallel to the gravity axis), the X axis can be the horizontal axis (e.g., horizontal axis), and the Y axis can be the longitudinal axis. However, in other examples, these axes can have other orientations. Figure 1A The rotation axis 180 of the sun gear 130 is further provided for reference. In the illustrated example, the modal planetary gearset 104 and the differential meshing compound planetary gearset 105 are coaxially arranged. Other electrically driven transmissions described herein also employ a coaxial arrangement of the modal planetary gearset and the differential. This allows the electrically driven transmission to achieve ideal space efficiency.

[0037] like Figure 1A As shown, the electric vehicle 103 may further include a control system 150 having a controller 152. The controller 152 may include a microcomputer whose components include a processor 154 (e.g., a microprocessor unit), input / output ports, and an electronic storage medium 156 (e.g., a read-only memory chip, random access memory, survivability memory, a data bus, etc.) for executable programs and calibration values. The storage medium may be programmed with computer-readable data representing instructions that are executable by the processor for performing the methods, control techniques, etc. described herein, as well as other variations that are anticipated but not specifically listed. Thus, the electronic storage medium 156 may store instructions that, when executed by the processor 154, cause the controller 152 to perform the various method steps described herein.

[0038] The controller 152 can receive various signals from sensors 158 coupled to various areas of the electric vehicle 103, particularly the electric axle 100. For example, the sensors 158 may include one or more motor speed sensors (described in detail below), shaft / gear speed sensors, thermocouples, pressure sensors, pedal position sensors for detecting operator-operated pedals (e.g., an accelerator pedal and / or a brake pedal), wheel speed sensors, etc. Input devices 160 (e.g., an accelerator pedal, a brake pedal, a gear selector, combinations thereof, etc.) can further provide input signals indicative of the operator's vehicle control intent.

[0039] Upon receiving Figure 1A After receiving signals from various sensors 158, the controller 152 processes the received signals and adjusts the components using various actuators 162 of the vehicle components based on the received signals and instructions stored in the memory of the controller 152. For example, the controller 152 may receive an accelerator pedal signal indicating that the operator desires to adjust the vehicle's acceleration. In response, the controller 152 may command operation of an inverter electrically coupled to the motor that powers the mode planetary gear set to increase the power delivered from the motor to the transmission 102. For example, other controllable components in the vehicle may function in a similar manner with respect to sensor signals, control commands, and actuator adjustments. Furthermore, the control system 150 may be used with any of the electric axle systems and transmissions described herein.

[0040] The controller 152 may include instructions that, when executed, may 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, when the vehicle is traveling at a lower speed, the electric axle 100 may operate in the first mode. 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 shifting sequence may also be executed in reverse order by mode. In addition, the shifting sequence may be performed out of sequence, so that modes may be skipped as needed. For example, the electric axle may be commanded to start in the second mode, or to downshift from the third mode to the first mode. The control system 150 described above may be used for any of the electric axles and transmissions described herein.

[0041] Figure 1B Shows Figure 1A A lever diagram 190 of the electric axle 100 structure is depicted in FIG. Figure 1A The three functions of the mode clutch 120 shown in the accompanying drawings correspond to the first mode, the second mode and the third mode, respectively, and are represented by devices 170, 172 and 174. However, it will be understood that the mode clutch 120 can be configured to perform the mode switching function as a clutch unit. As described above, in the first mode, the carrier 108 is fixed, in the second mode, the sun gear 106 is fixed, and in the third mode, the carrier 108 and the sun gear 106 are rotationally coupled to each other. The input end of the mode planetary gear set 104 is represented by arrow 176, and the output end of the differential meshing planetary compound planetary gear set 105 is represented by arrows 178 and 179. In the illustration, the direction of rotation of the transmission input end is the same as the direction of rotation of the transmission output end. However, other transmission designs can also be used.

[0042] The formula provided below is the same as Figures 1A-1B However, it will be appreciated that the transmission structure may be modified to exhibit other speed relationships between components without departing from the present disclosure.

[0043] Where: S =Specify the sun gear speed

[0044] ω C =Specify the rotation speed of the bracket

[0045] ω R =Specify the speed of the ring gear

[0046] C2=Bracket(132)

[0047] R2=Ring gear(122)

[0048] S2=sun gear (130)

[0049] R4=R5=ring gear(114)

[0050] P4-5=Planetary gear set (110)

[0051] P5 = Planetary gear set (116)

[0052] S5=Sun gear box (118)

[0053] S4=Sun gear box (106)

[0054] C4=C5=Bracket(108)

[0055] e2 = ratio of ring gear to sun gear R2 / S2

[0056] e4 = ratio of ring gear to sun gear R5 / S4

[0057] e5 = ratio of ring gear to sun gear R5 / S5

[0058] Speed ​​relationship of differential meshing planetary compound gear set (ω)

[0059] ω C2 (1-e2)=ω S2 -ω R2 e2 (Equation 1)

[0060] For a 1:1 differential equation, when ω C2 =-ω S2 ω R2 =0.

[0061]

[0062] e2=2

[0063] Ravigneaux gear set (104) three-speed relationship (ω)

[0064] ω C4 (1+e4)=ω S4 +ω R4 e4 (Equation 2)

[0065] ω C5 (1-e5)=ω S5 -ω R5 e5 (Equation 3)

[0066] Because: C4 =ω C5 (Combining equations 2 & 3)

[0067] And: R4 =ω R5

[0068] ω R5 (e4+e5)=ω S5 (1+e4)-ω S4 (1-e5)(Equation 4)

[0069] Mode 1 Bracket 4-5 Fixed, ω C5 =0

[0070]

[0071] Mode 2 Sun gear 4 is fixed, ω S4 =0

[0072]

[0073] Mode 3 Sun 4 Lock Bracket, ω 4-5S4 =ω C5

[0074] ω C5 =ω S4 =ω R4 =ω R5 (From Equation 2) Locking the planetary gear ω C5 =ω R5 =ω S5 (From Equation 3) Locking the planetary gear

[0075] Figure 2A An example of an electric axle 200 is shown with a transmission 201, which also includes a modal planetary gear set 202, a modal clutch 203, and a differential meshing planetary compound gear set 204. The differential meshing planetary compound gear set 204 again 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 planetary gear sets 232 and 234 rotationally fixed to the carrier 108.

[0076] Figure 2A The differential meshing planetary compound planetary gear set 204 and Figure 1A The differential meshing planetary compound planetary gear set 105 described in has a similar design. In addition, Figure 2A The mode clutch 203 and Figure 1A The mode clutch 120 shown in FIG has a similar design. Therefore, for the sake of brevity, redundant descriptions of the structural and functional characteristics of these components are omitted.

[0077] The mode planetary gear set 202 is again depicted as a Ravigneaux gear set that switches between three modes via a mode clutch 203. However, we have also considered an electric axle with more speeds, such as a four-speed electric axle. In addition, the Ravigneaux planetary gear set 202 has a set of planetary gears 208 connected to a set of planetary gears 210 and another set of planetary gears 212. The planetary gear sets 208 and 210 are arranged as a stepped planetary assembly. Therefore, the gears in the planetary gear set 208 mesh with the sun gear 214, and the gears in the planetary gear set 210 mesh with the ring gear 216. The mode planetary gear set 202 also includes a set of planetary gears 212 and another sun gear 220, similar to Figure 1A 208 and 210 form a stepped planetary gear set, and planetary gear set 212 is rotationally coupled to carrier 222, which can be fixed by clutch 203. However, in other examples, the Ravigneaux gear set can also have other numbers of planetary gear sets.

[0078] Figure 2B Shows Figure 2A Lever diagram 290 of the electric axle structure described in. Figure 2A The three functions of the mode clutch 203 shown in the figure correspond to the first mode, the second mode and the third mode, respectively, and are represented by devices 270, 272 and 274, respectively. However, it will be understood that the mode clutch 203 can be configured to perform the mode switching function as a clutch unit. As described above, in the first mode, the carrier 222 is fixed, in the second mode, the sun gear 214 is fixed, and in the third mode, the carrier 222 and the sun gear 214 are rotationally coupled to each other. The input end of the mode planetary gear set 202 is represented by arrow 276, and the output end of the differential meshing planetary compound planetary gear set 204 is represented by arrows 278 and 279. In the illustration, the direction of rotation of the transmission input end is the same as the direction of rotation of the transmission output end. However, other transmission designs can also be used.

[0079] The formula provided below is the same as Figures 2A-2B However, it will be appreciated that the transmission structure may be modified to exhibit other speed relationships between components without departing from the present disclosure.

[0080] Where: S =Specify the sun gear speed

[0081] ω C =Specify the rotation speed of the bracket

[0082] ω R=Specify the speed of the ring gear

[0083] C2=Bracket(238)

[0084] R2=Ring gear (230)

[0085] S2=Sun gear (236)

[0086] R4=R5=ring gear(216)

[0087] P5a=Planetary gear set (212)

[0088] P5b = Planetary gear set (210)

[0089] P4=Planetary Gear Set (208)

[0090] S5=Sun gear (220)

[0091] S4=Sun gear (214)

[0092] C4=C5=Bracket(222)

[0093] e2 = ratio of ring gear to sun gear R2 / S2

[0094] e4 = ratio of ring gear to sun gear R5 / S4

[0095] e5 = ratio of ring gear to sun gear R5 / S5

[0096] N = number of gear teeth

[0097] Speed ​​relationship of differential meshing planetary compound gear set (ω)

[0098] ω C2 (1-e2)=ω S2 -ω R2 e2 (refer to formula 1)

[0099] For 1:1 differentiation, when ω R2 = 0, let ω C2 =-ω S2

[0100]

[0101] e2=2

[0102] Ravigneaux gear set (202) three-speed relationship (ω)

[0103]

[0104] (Combining formulas 3 and 5)

[0105]

[0106] Because: P4 =ω P5b (Combined with formula 7 & 8)

[0107]

[0108] Because: C5 =ω C5 (Combined with formula 6 & 11)

[0109]

[0110] Mode 1 Bracket 4-5 Fixed, ω C5 =0

[0111]

[0112] Mode 2 Sun gear 4 is fixed, ω S4 =0

[0113]

[0114] Mode 3 Sun Gear 4 Locking Bracket, ω 4-5S4 =ω C5

[0115] ω C5 =ω S4 =ω R5 =ω R4 (From Equation 11) Locking the Planetary Gear

[0116] ω C5 =ω R5 =ω S5 (From Equation 3) Locking the planetary gear

[0117] Figure 3A An electric axle 300 is shown with a transmission 302 including a Ravigneaux planetary gear set 304 and a differential meshing planetary compound gear set 306. The structures of the Ravigneaux planetary gear set 304 and the differential meshing planetary compound gear set 306 are similar to Figure 1A The mode planetary gear set 104 and the differential meshing planetary compound gear set 105 are shown in FIG. The transmission 302 also includes a mode clutch 308, which enables the transmission to achieve a three-speed function, similar to Figure 1A The transmission 102 is shown in FIG.

[0118] Figure 3A The electric motor 310 is specifically depicted in the electric axle 300. As described herein, the electric motor associated with the electric axle may be a traction motor (eg, a motor generator). Figure 3A The motor 310 depicted in FIG. 3 is concentrically arranged with the differential meshing planetary compound gear set 306 and the Ravigneaux-type planetary gear set 304. For illustrative purposes, the motor 310 is shown with its rotor 309 having an inner diameter 307 circumferentially surrounding at least a portion of the transmission, particularly the Ravigneaux-type planetary gear set 304. However, as discussed in greater detail herein, the motor can have a variety of suitable locations and orientations. In the illustrated example, at least a portion of the meshing planetary compound gear set is located within an internal opening of the motor.

[0119] Figure 3A Also depicted are a differential locking clutch 312 and an axle disconnect clutch 314. The differential locking clutch 312 is configured to rotationally couple the carrier 316 and ring gear 318 of the differential mesh planetary compound gear set 306. This allows the differential to be selectively locked to enhance axle performance, particularly in low-traction operating conditions (e.g., four-wheel drive vehicles). The differential locking clutch 312 allows the output shafts 342 and 343 (e.g., axles) of the differential mesh planetary compound gear set 306 to be selectively locked for rotation relative to each other. The axle disconnect clutch 314 allows the differential mesh planetary compound gear set 306 to be selectively disconnected from the Ravigneaux mode planetary gear set 304. Furthermore, the axle disconnect clutch 314 selectively decouples the ring gear 318 of the differential mesh planetary compound gear set 306 from the ring gear 320 of the Ravigneaux mode planetary gear set 304. Axle disconnect clutch 314 allows the differential meshing planetary compound gear set 306 to selectively decouple from the Ravigneaux mode planetary gear set 304. One or both of differential locking clutch 312 and axle disconnect clutch 314 can be integrated into any transmission described herein. Axle disconnect clutch 314 can improve the efficiency of the vehicle driveline for towing, hauling a series of decked vehicles, or when using one electric axle as a marker axle in a tandem axle configuration.

[0120] Axle 322 can be connected to input shaft 323 of transmission 302. Input shaft 323 connects Ravigneaux-mode planetary gearset 304 and motor 310. As described herein, an axle can include inner races, roller elements (e.g., cylindrical rollers, spherical balls, tapered cylindrical rollers, needle rollers, bushings, etc.), and outer races. In the illustrated example, axle 324 is connected to sun gear 326 in Ravigneaux-mode planetary gearset 304. Additionally, an axle 328 is connected to a carrier 330 in the Ravigneaux-mode planetary gearset. In the illustrated example, another axle 332 is connected to carrier 330 and ring gear 320. Additionally, in the illustrated example, axles 334 and 346 are connected to shafts 336 and 348 and / or other suitable mechanical structures connected to ring gears 318 and 320. Axle 338 can be connected to ring gear 318, axle 340 can be connected to output shaft 343 and carrier 316, and axle 344 can be connected to carrier 316. In other embodiments, the axles in the transmission can have other suitable arrangements.

[0121] Figures 3B-3E Different electric motor and gear train arrangements for inputting the Ravigneaux mode planetary gear set 304 in different electric axle configurations are described. The configurations of the Ravigneaux mode planetary gear set 304, the differential meshing planetary compound planetary gear set 306, the mode clutch 308, the differential locking clutch 312, and the axle disconnect clutch 314 are similar. Figure 3A The components shown in FIG are similar in structure and layout. Therefore, for the sake of brevity, redundant description is omitted. In addition, it will be understood that the electromechanical and input gear train arrangement can be applied to electric axles in which the Ravigneaux gear set includes a stepped planetary arrangement, such as Figure 2A Therefore, for the sake of brevity, redundant descriptions of overlapping components are omitted.

[0122] Figure 3B Specifically shown is a motor shaft 349 with a motor 350 that is concentric with one of the output shafts 343 and located axially outwardly 352 of the Ravigneaux-type planetary gear set 304. In the illustration, a portion of the output shaft 343 extends through an opening in the motor 350. This improves the space efficiency of the motor shaft. Figure 3B Further shown is an axle 353 connected to the motor 350. The electric axle includes additional axles arranged in the same manner as Figure 3A For example, generally speaking, there are axles on rotating shafts and gears. Figures 3C-3E The other electric axles shown also include similar axle arrangements in the Ravigneaux mode planetary gear set 304, the differential meshing planetary compound gear set 306, the axle disconnect clutch 314, and the differential locking clutch 312. However, other axle arrangements may be used, and Figures 3A-3EIn any of the illustrated electric axle configurations, at least one of the differential locking clutch 312 and the axle disconnect clutch 314 may be omitted. As described above, the axle disconnect clutch 314 and the differential locking clutch 312 may be dog clutches, synchronizers, friction clutches (e.g., wet friction clutches), radial clutches, face clutches, crank clutches, magnetic clutches, combinations thereof, or the like. Furthermore, the axle disconnect clutch 314 and the differential locking clutch 312 may be actuated by electromechanical actuators, pneumatic actuators, hydraulic actuators, electromagnetic actuators, barrel cam actuators, combinations thereof, or the like. As previously described, a shift fork, such as a translating or rotating shift fork, may be dedicated to actuating at least a portion of the clutches described herein.

[0123] Figure 3C An electric axle 359 is shown with two electric machines 360 and 362, which are parallel to output shafts 342 and 343, respectively, and mechanically connected to the input of transmission 302 via gear trains 363 and 367. Gear 365 meshes with gears in each gear train 363 and 367 and provides a mechanical connection between shaft 364, which is rotationally connected to the input of Ravigneaux-type planetary gearset 304. It will be appreciated that electric machines 362 and corresponding gear trains 367 are optional, and thus, in other embodiments, the electric axle may be omitted. More generally, various gear train layouts connected to the input of a Ravigneaux-type planetary gearset may be used. For example, the gear trains used to connect the first and / or second electric machines may include additional gear paths. In other examples, one or more planetary gearsets (e.g., simple planetary gearsets, compound planetary gearsets, etc.) may be used to connect one or more electric machines to the Ravigneaux-type planetary gearset. For example, a planetary gear set coaxial with the motor can be used to connect the motor to the Ravigneaux mode planetary gear set. In addition, a planetary gear set coaxial with the rotation axis of the output shaft 343 can also be used to rotationally couple the motor to the Ravigneaux mode planetary gear set. In any embodiment in which one or more planetary gear sets provide an input connection to the Ravigneaux mode planetary gear set, the carrier in the planetary gear set can be fixed, the ring gear in the planetary gear set can be fixed, or the sun gear in the planetary gear set can be fixed. In addition, additional gear transmissions, chains, belts, combinations thereof, etc. can also be used to transmit mechanical power between one or more motors and the Ravigneaux mode planetary gear set.

[0124] Furthermore, it will be appreciated that any of the electric axles described herein can include a second electric motor, if desired. For example, in one example, the second electric motor can be coupled to the input of the Ravigneaux mode planetary gearset in the same mechanical manner as the first electric motor is coupled to the input of the Ravigneaux mode planetary gearset. In another example, the second electric motor can be coupled to the input of the Ravigneaux mode planetary gearset using a different gear arrangement to achieve a different motor-to-mode planetary gearset input ratio, thereby providing the second electric motor with different characteristics than the first electric motor. Furthermore, in some cases, a disconnect clutch can be provided between the second electric motor and the Ravigneaux mode planetary gearset to decouple the second electric motor from the Ravigneaux mode planetary gearset, further improving efficiency.

[0125] Figure 3D An electric shaft 369 is shown with an electric motor 370 arranged perpendicular to the axis of rotation of the transmission 302. A gear train 372 including bevel gears 374 provides input to the Ravigneaux planetary gear set 304. Figure 3C The exemplary electric bridge 359 described in FIG. 1 is similar to that of FIG. 1 , considering the addition of a second motor and a second motor disconnect clutch. In addition, a bevel gear 387 is also provided in the gear train 372 for connecting the gear train to an input shaft 388.

[0126] Figure 3E An electric axle 379 is shown with an electric motor 380 arranged perpendicular to the axis of rotation of the transmission 302. In the illustrated example, the electric axle includes an input gear train 382 with multiple gear reducers 383 and 384, which can be selected via a clutch 385. This allows the selection of gears in the transmission to be further expanded, thus making the operation of the electric machine more efficient. Figure 3C Similar to the exemplary electric axle 359 described in , the addition of a second electro-mechanical unit and a second electro-mechanical disconnect clutch is also contemplated. However, as described above, various gear train arrangements are also contemplated that may provide input to the Ravigneaux mode planetary gear set.

[0127] It is understood that the electric axle includes Figures 3A-3E In addition, any different motor and / or input gear train arrangement can be used in any transmission structure or transmission structure combination described herein.

[0128] Figure 4Another example of a transmission 400 for an electric axle is shown. In the illustrated example, the transmission 400 again includes a differential meshing planetary compound gear set 404, a Ravigneaux planetary gear set 406, and a mode clutch 408. The arrangement of the differential meshing planetary compound gear set 404 and the Ravigneaux mode planetary gear set 406 is similar to Figure 1A The differential meshing planetary compound gear set 105 and the modal planetary gear set 104 are shown to be identical. Therefore, redundant descriptions of overlapping components are omitted for the sake of brevity.

[0129] In addition, the simple planetary gear set 410 is directly connected to the sun gear 412 in the Ravigneaux mode planetary gear set 406 through the carrier 413. In addition, the sun gear 414 in the simple planetary gear set can serve as the input end of the transmission. Figure 4 In the illustrated example, the ring gear 418 of the simple planetary gear set is fixed. However, other simple planetary gear set configurations are also possible. For example, in the simple planetary gear set 410, the ring gear 418 can be connected to the sun gear 412 of the Ravigneaux-type planetary gear set 406. In the simple planetary gear set 410, the carrier 413 can be fixed, and the sun gear 414 of the simple planetary gear set 410 can serve as the input of the transmission.

[0130] Figure 5 Another example of a transmission 500 for an electric axle is shown. In the illustrated example, the transmission 500 includes a differential meshing planetary compound gear set 502, a Ravigneaux mode planetary gear set 504, and a mode clutch 506. Figure 1A The transmission 102 shown in FIG. Figure 5 As shown, the meshing planetary compound gear set 508 is directly connected to the sun gear 510 in the Ravigneaux mode planetary gear set 504 through the carrier 511. The sun gear 512 of the meshing planetary compound planetary gear set 508 serves as the input end of the transmission 500. In addition, Figure 5 In the embodiment of the invention, the ring gear 514 of the meshing planetary compound gear set 508 is fixed. However, other meshing planetary compound gear set configurations may be used. For example, in the meshing planetary compound gear set 508, the ring gear 514 may be connected to the sun gear 510 of the Ravigneaux mode planetary gear set 504, while in the meshing planetary compound gear set 508, the carrier 511 may be fixed, and the sun gear 512 of the meshing planetary compound gear set 508 may serve as the input of the transmission.

[0131] Figure 6Another example of a transmission 600 for an electric axle is shown. In the illustrated example, transmission 600 again includes a differential meshing planetary compound gear set 602 and a Ravigneaux mode planetary gear set 604 with a mode clutch 605. However, in this example, a simple planetary gear set 606 is positioned between the differential meshing planetary compound gear set 602 and the Ravigneaux mode planetary gear set 604. Specifically, in the illustrated example, a sun gear 608 in simple planetary gear set 606 is rotationally coupled to a ring gear 610 in the Ravigneaux mode planetary gear set 604, a carrier 611 in simple planetary gear set 606 is rotationally coupled to a ring gear 612 in the differential meshing planetary compound gear set 602, and a ring gear 614 in simple planetary gear set 606 is fixed. However, other planetary gear set configurations may also be employed. For example, in the simple planetary gear set 606, the ring gear 614 can be coupled to the ring gear 612 in the differential meshing planetary compound planetary gear set 602, in the simple planetary gear set 606, the carrier 611 can be fixed, and the sun gear 608 in the simple planetary gear set 606 can be rotationally coupled to the ring gear 610 in the Ravigneaux mode planetary gear set 604.

[0132] Figure 7 Another example of a transmission 700 for an electric axle is shown. In the illustrated example, transmission 700 again includes a differential meshing planetary compound gear set 702 and a Ravigneaux mode planetary gear set 704 with a mode clutch 705. The transmission also includes another meshing planetary compound gear set 706, which includes a carrier 708 rotationally coupled to a ring gear 710 in the differential meshing planetary compound gear set 702. The meshing planetary compound gear set 706 also includes a sun gear 712 rotationally coupled to a ring gear 714 in the Ravigneaux mode planetary gear set 704. Furthermore, in the illustrated example, the ring gear 716 in the meshing planetary compound gear set 706 is fixed. However, as previously described, other planetary gear set configurations are also possible. For example, in the meshing planetary compound gear set 706, the ring gear 716 can be coupled to the ring gear 710 in the differential meshing planetary compound gear set 702, and in the meshing planetary compound gear set 706, the carrier 708 can be fixed, and the sun gear 712 in the meshing planetary compound gear set 706 can be rotationally coupled to the ring gear 714 in the Ravigneaux mode planetary gear set 704. It can be understood that Figure 4-7 The transmission shown, as well as other transmissions described herein, may include an axle disconnect clutch and / or a differential lock clutch.

[0133] Figure 8Another example of a transmission 800 for an electric axle is shown. However, in the illustrated example, the ring gear 803 in the Ravigneaux mode planetary gear set 802 is rotationally coupled to a limited slip differential 804 that is configured to limit the speed difference between output shafts 806 and 808 using clutches, friction, a bias ratio, and / or other suitable devices and methods.

[0134] Figure 9 Another example of a transmission 900 for an electric axle is shown. In the illustrated example, transmission 900 again includes a differential meshing planetary compound planetary gear set 902. Transmission 900 also includes a Ravigneaux-mode planetary gear set 904, which differs in structure from the previously described Ravigneaux-mode planetary gear sets. Specifically, Ravigneaux-mode planetary gear set 904 includes a carrier 906 rotationally coupled to a ring gear 908 of differential meshing planetary compound planetary gear set 902. Furthermore, a sun gear 910 in Ravigneaux-mode planetary gear set 904 meshes with a set of planet gears 912, serving as inputs to Ravigneaux-mode planetary gear set 904. Furthermore, a mode clutch 914 is configured to secure a ring gear 920 meshed with planet gears 912 in a first mode, secure a sun gear 916 meshed with planet gears 918 in a second mode, and rotationally couple ring gear 920 and sun gear 916 in a third mode. In the illustrated example, a set of planetary gears 918 meshes with a set of planetary gears 912. Planetary gear set 918 and planetary gear set 912 are rotatably mounted on carrier 906 in such a manner that the input and output of the Ravigneaux-type planetary gear set can be varied. However, other planetary gear set configurations may also be employed, including arrangements in which planetary gears 912 include stepped planetary assemblies.

[0135] Figure 10Another example of a transmission 1000 for an electric axle is shown. In the illustrated example, transmission 1000 again includes a Ravigneaux planetary gearset 1002. However, in the illustrated example, the ring gear 1003 in Ravigneaux planetary gearset 1002 is rotationally coupled to a carrier 1006 in a double sun differential 1008. Double sun differential 1008 also includes a first sun gear 1010 and a second sun gear 1012 connected to output shafts 1014 and 1018, respectively. Planet gear 1004 meshes with planet gear 1016 and sun gear 1010, and planet gear 1016 meshes with sun gear 1012. In the illustrated example, planet gears 1004 and 1016 are rotatably mounted on carrier 1006. The double sun differential can be either an open differential or a limited-slip differential, utilizing clutches, friction, an offset ratio, and / or other suitable devices and methods to limit the speed difference between output shafts 1014 and 1018. It will be appreciated that the Ravigneaux-type planetary gear sets described herein may be connected to other types of differentials (eg, locking differentials, open differentials, etc.).

[0136] Figure 11 Another example of a transmission 1100 for an electric axle is shown. The transmission 1100 again includes a Ravigneaux mode planetary gear set 1102 with a mode clutch 1104. The transmission 1100 also includes an open differential 1106 with a differential carrier 1108 driven by a ring gear 1110 in the Ravigneaux planetary gear set 1102. The differential 1106 also includes differential pinions 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 rotationally coupled to output shafts 1114 and 1116. Furthermore, it will be appreciated that the differential 1106 (e.g., Figure 11 shown) and Figure 8 and Figure 10 The differentials shown are all examples of double sun gear differentials.

[0137] Furthermore, it is understandable that Figure 1A-11 The differentials described in the specification can be further combined with springs, clutches or cones, cam ramps, helical, worm and spur gears, viscous, gerotor and electronic components to create limited slip differentials (LSDs) (such as torque sensing limited slip differentials), automatic torque biasing (ATB) limited slip differentials, clutch pack limited slip differentials, bevel gear differentials, double positive differentials, reduction differentials, etc.

[0138] The output shaft of the electric axle described herein can be directly connected to the drive wheel, the hub-end gear reducer (such as a planetary gear reducer in the hub), or other appropriate mechanical components for use in vehicles requiring differential output (such as cars, trucks, boats, all-terrain vehicles, commercial vehicles, light vehicles, off-highway vehicles, mining vehicles, rail vehicles, etc.) and other applications (such as manufacturing applications such as manufacturing machinery, industrial applications such as industrial machinery, etc.). When the electric axle described herein is used in a vehicle, it is understood that the transmission can be used as a drive shaft for electric vehicles (EVs) such as all-electric vehicles (such as battery electric vehicles (BEVs)) and hybrid electric vehicles. Therefore, in some examples, a vehicle using the transmission described herein may have an internal combustion engine (such as a spark ignition engine, a compression ignition engine, a combination thereof, etc.). In addition, the electric axle described herein may have an axle disconnect and / or differential lock function.

[0139] The gears in the planetary gear set can be spur gears or helical gears. As mentioned above, the second motor in the electric axle described herein is optional. Moreover, in one example, the gears used to mechanically couple the motors to the transmission input can be identical and mesh with a final gear on the output centerline. In another example, the transmission associated with the second motor can be different from the transmission associated with the first motor and mesh with a final gear on the output centerline. Furthermore, in one example, the gear transmission associated with the second motor can include a clutch to decouple the second motor from the mode planetary gear set in certain circumstances, thereby further improving efficiency.

[0140] Furthermore, in one example, the transmission associated with the second motor can mesh with the transmission associated with the first motor before the final gear on the output centerline. Furthermore, in one example, the transmission associated with the second motor can have a different gear ratio and mesh with the transmission associated with the first motor before the final gear on the output centerline.

[0141] also, Figure 1A-11 The three-speed planetary gear set shown in one mode may have a 1:1 gear ratio in one use case. However, the electric axle can have a variety of gear ratios, which can be selected based on the end-use design goals of the vehicle platform. Therefore, Figure 1A-11 The ratios shown in are those used in the case where they are used, and different ratios can be used for electric axles.

[0142] also, Figures 3A-3E The exact positions and numbers of axles in the electric axle structure shown in FIG. 5 are indicative and exemplary, and it will be appreciated that other axle layouts, types, numbers, etc. may be used in other examples.

[0143] Furthermore, it will be appreciated that the electric axle may utilize one or more intersecting electric motors that may be connected to the input of the transmission via hypoid gears or other suitable helical or bevel gears. In such an example, the electric motor may mesh with the hypoid gears via a mating pinion, and there may be other gear channels and / or shiftable gears between the electric motor and the pinion. In various examples, the variable speed gears may be mounted on any of the parallel mating shafts. Furthermore, additional gear channels may be added to the electric shaft if desired. Furthermore, the planetary gear sets described herein may take the form of simple planetary gear sets, meshing planetary compound planetary gear sets, stepped planetary compound planetary gear sets, and / or magnetic planetary gear sets.

[0144] Furthermore, it is understandable that Figures 3A-3E The various motor arrangements shown can be used with any of the electric axles described herein, e.g. Figure 1A 、 2A , any electric axle shown in 4-11 or a combination of the electric axles. In addition, we also envision different combinations of motor structures and transmission structures, which include multiple features from different embodiments.

[0145] The present invention will be further described below. In one aspect, the present invention provides an electric axle system comprising: an electric motor; a multi-speed transmission rotationally coupled to the electric motor, rotationally coupled to two output shafts, and comprising: a Ravigneaux gear set rotationally coupled and coaxially positioned with a differential; and a mode clutch configured to selectively: fix a carrier or ring gear in the Ravigneaux gear set; fix a sun gear in the Ravigneaux gear set; and rotationally couple the carrier or ring gear to the sun gear in the Ravigneaux gear set. In one example, the differential can be a meshing planetary compound planetary gear set. In another example, the ring gear in the Ravigneaux gear set can be rotationally coupled to a ring gear in a meshing planetary compound planetary gear set of the differential. In one example, the electric axle system can further include a locking clutch configured to selectively rotationally couple a ring gear in the differential to a carrier in the differential to lock the rotation of the two output shafts. In another example, the electric axle system may further include a disconnect clutch configured to selectively disconnect the Ravigneaux gear set from the differential. Additionally, in one example, the differential may be a dual sun gear planetary gear set. In another example, the electric machine may be positioned coaxially, parallel to, or intersecting the Ravigneaux gear set and the differential. In another example, the electric axle system may further include a second electric motor rotationally coupled to the multi-speed transmission. In another example, the Ravigneaux gear set and the differential are at least partially located within the inner diameter of the electric motor rotor. In another example, the electric axle may further include a third planetary gear set rotationally coupled to the input end of the Ravigneaux gear set, or rotationally coupled to the input end of the differential and the output end of the Ravigneaux gear set.

[0146] In another aspect, a method for operating an electric axle system is provided, the method comprising operating a mode clutch to: in a first mode, fix a carrier or ring gear in a Ravigneaux gear set; in a second mode, fix a sun gear in the Ravigneaux gear set; and in a third mode, rotationally couple the carrier or ring gear to the sun gear in the Ravigneaux gear set. The electric axle system comprises: an electric motor; a multi-speed transmission rotationally coupled to the electric motor, rotationally coupled to two output shafts, and comprising: a Ravigneaux gear set rotationally coupled and coaxially positioned with a differential; and a mode clutch. In one example, the differential may be a meshing planetary compound gear set; the ring gear in the Ravigneaux gear set may be rotationally coupled to a ring gear in a meshing planetary compound gear set of the differential; and the sun gear and carrier in the meshing planetary compound gear set of the differential may be rotationally coupled to separate output shafts. In one example, the method may further comprise operating a locking clutch to rotationally couple the ring gear in the differential with the carrier in the differential to lock the rotation of the two output shafts. In another example, the method may further include operating a disconnect clutch to selectively disconnect the Ravigneaux gear set from the differential.

[0147] In another aspect, an electric axle system is provided, comprising: an electric motor; a multi-speed transmission rotationally coupled to the electric motor, and including: a Ravigneaux gear set rotationally coupled and coaxially positioned to a differential meshing planetary compound gear set; and a mode clutch configured to shift the Ravigneaux gear set between three modes; wherein the differential meshing planetary compound gear set is rotationally coupled to two output shafts. In one example, the mode clutch can be configured to:

[0148] In a first mode, the carrier or ring gear in the Ravigneaux gear set is fixed; in a second mode, the sun gear in the Ravigneaux gear set is fixed; and in a third mode, the carrier or ring gear in the Ravigneaux gear set is rotationally coupled to the sun gear. In one example, the electric axle system may further include a locking clutch configured to selectively rotationally couple the ring gear in the differential meshing planetary compound gear set to the carrier in the differential meshing planetary compound gear set to lock the rotation of the two output shafts; and a disconnecting clutch configured to selectively disconnect the Ravigneaux gear set from the differential meshing planetary compound gear set. In one example, in the system, the ring gear in the Ravigneaux gear set may be rotationally coupled to the ring gear in the differential meshing planetary compound gear set; the sun gear in the differential meshing planetary compound gear set may be rotationally coupled to the first shaft; and the carrier in the differential meshing planetary compound gear set may be rotationally coupled to the second shaft. In one example, the electric axle system may further include a second meshing planetary compound gear set rotationally coupled to the Ravigneaux gear set and the differential meshing planetary compound gear set. In another example, the mode clutch may be configured to: in a first mode, fix the ring gear of the Ravigneaux gear set; in a second mode, fix the sun gear of the Ravigneaux gear set; and in a third mode, rotationally couple the ring gear and the sun gear of the Ravigneaux gear set.

[0149] Figure 1A-11Example configurations of various elements positioned relative to each other are shown. If elements shown in a figure are in direct contact or directly coupled to each other, then, in at least one example, these elements may be referred to as being in direct contact or directly coupled, respectively. Similarly, in at least one example, elements shown as being adjacent or adjacent to each other may be adjacent or adjacent to each other, respectively. For example, elements in face-to-face contact may be referred to as face-to-face contact elements. As another example, in at least one example, elements placed apart from each other, with only space between them and no other elements, may be referred to as being placed apart from each other. As another example, elements displayed above / below, to the sides of, or to the left / right of each other relative to each other may be referred to as such elements. Furthermore, as shown in the figure, in at least one example, the topmost element or element point may be referred to as the "top" of the element, and the bottommost element or element point may be referred to as the "bottom" of the element. As used herein, the terms top / bottom, upper / lower, and above / below may be used to describe the relative positioning of elements in the figure relative to each other, relative to the vertical axis in the figure. Thus, in one example, an element displayed above other elements is positioned vertically above the other elements. As another example, the shapes of elements depicted in the figures may be referred to as having these shapes (e.g., as circular, linear, planar, curved, rounded, chamfered, beveled, or the like). Furthermore, in one example, elements that are coaxial with one another may be referred to as coaxial elements. Furthermore, in at least one example, elements that are shown intersecting one another may be referred to as intersecting elements or intersecting one another. Furthermore, in one example, elements that appear to be within another element or appear to be outside another element may be referred to as intersecting elements. In other examples, elements that are offset from one another may also be referred to as "offset elements."

[0150] Motor and shift control logic / programs, inverters, electronic control units (ECUs), memory storage, throttle, brake, speed and inclination sensors, etc., shift actuators, etc. can further be used in any of the electric axles and transmissions described herein.

[0151] Figure 1A-11 A method for operating an electric axle is provided, wherein a transmission switches between two of three modes based on vehicle operating conditions. The method may further include selectively locking the differential by operating a locking clutch in the differential. The method may even further include selectively disconnecting the axle by operating a disconnect clutch.

[0152] Furthermore, the axles and transmissions described herein may include a control system comprising a controller having a processor and a memory storing instructions for executing the method steps described herein. More specifically, the control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by a system including the controller in conjunction with various sensors and actuators. Furthermore, portions of the methods may be physical actions taken 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, multi-tasking, multi-threading, and the like. Therefore, the various actions, operations, and / or functions illustrated may be performed in the order shown, in parallel, or omitted in some cases. Similarly, the order of processing is not necessarily required to achieve the features and advantages of the examples described herein and 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 specific strategy being employed. Furthermore, the described actions, operations, and / or functions may graphically represent code to be programmed into non-transitory memory of a computer-readable storage medium in a system, where the described actions are implemented by executing the instructions in a system comprising various hardware components in conjunction with an electronic controller. If desired, one or more method steps described herein may be omitted.

[0153] While various embodiments have been described above, it should be understood that these embodiments are illustrative only and are not intended to be limiting or restrictive. It should be understood that the configurations and routines disclosed herein are exemplary in nature, and these specific examples should not be considered limiting, as many variations are possible. For example, the above-described technology can be applied to powertrains that incorporate different types of propulsion sources, including different types of electric motors, internal combustion engines, and / or transmissions. The technology can be used alone or in combination with other powertrain systems, including, but not limited to, tandem axles, electric tag axles, P4 axles, HEVs, BEVs, agricultural vehicles and machinery, marine vehicles and machinery, motorcycles, recreational vehicles, and machinery and propulsion systems, including on- and off-highway vehicles, mining vehicles, rail vehicles, manufacturing machinery, and industrial machinery. 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 relevant art that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter.

[0154] The following claims particularly point out certain combinations and subcombinations regarded as novel and non-obvious. These claims may refer to "an" element or a "first" element or its equivalent. These claims should be understood to include 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 amendment of the present claims or by presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, are also deemed included within the subject matter of the present disclosure.

Claims

1. An electric axle system, characterized in that: include: Motor; A multi-speed transmission rotatably connected to the motor, the multi-speed transmission rotatably connected to two output shafts, the multi-speed transmission comprising: a Lavigne-Herche gear set rotationally coupled and positioned coaxially with the differential; as well as a mode clutch that selectively: Secures the carrier or ring gear in a Ravigneaux gear set; securing the sun gear in the Ravigneaux gear set; and The carrier or ring gear in the Ravigneaux gear set is rotationally coupled to the sun gear.

2. The electric axle system of claim 1, wherein the differential is a meshing planetary compound gear set.

3. The electric axle system of claim 2, wherein a ring gear in the Ravigneaux gear set is rotationally coupled to a ring gear in the differential meshing planetary compound gear set.

4. The electric axle system according to claim 1, characterized in that A locking clutch is also included, which selectively rotationally couples the ring gear in the differential to the carrier of the differential to lock the rotation of the two output shafts.

5. The electric axle system according to claim 1, characterized in that: Also included is a disconnect clutch that selectively disconnects 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. The electric axle system of claim 1, wherein the motor is positioned coaxially, parallel to, or intersecting with the Ravigneaux gear set and differential.

8. The electric axle system according to claim 1, characterized in that Also included is a second electric machine rotationally coupled to the multi-speed transmission.

9. The electric axle system of claim 1, wherein the Ravigneaux gear set and the differential are located at least partially within an inner diameter of the motor rotor.

10. The electric axle system according to claim 1, wherein: A third planetary gear set is further included, wherein the third planetary gear set is rotationally coupled to the input end of the Ravigneaux gear set, or is rotationally coupled to the input end of the differential and the output end of the Ravigneaux gear set.

11. The electric axle system of claim 1 , wherein the mode clutch is configured to: In the first mode, the carrier or ring gear in the Ravigneaux gear set is fixed; In a second mode, the sun gear in the Ravigneaux gear set is fixed; and In the third mode, the carrier or ring gear in the Ravigneaux gear set is rotationally coupled to the sun gear.

12. The electric axle system according to claim 3, wherein: Also includes: a differential lock clutch that selectively couples the rotation of the ring gear in the differential meshing planetary compound planetary gear set to the carrier in the differential meshing planetary compound planetary gear set to lock the rotation of the two output shafts; as well as A disconnect clutch selectively disconnects the Ravigneaux gear set from the differential meshing planetary compound gear set.

13. The electric axle system of claim 3, wherein A ring gear in the Ravigneaux gear set is rotationally coupled to a ring gear in the differential meshing planetary compound gear set; and The carrier of the differential meshing planetary compound planetary gear set is rotationally coupled to an output shaft; and The sun gear in the differential meshing planetary compound planetary gear set is rotationally coupled to another output shaft.

14. The electric axle system according to claim 13, wherein: Also included is a second meshing planetary compound planetary gear set rotationally coupled to the Ravigneaux gear set and the differential meshing planetary compound planetary gear set.

15. The electric axle system according to claim 14, wherein: The ring gear in the differential meshing planetary compound planetary gear set is rotationally coupled to the carrier or ring gear in the Ravigneaux gear set.

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