Axle assemblies for low-floor vehicles

Abstract

The electric vehicle axle assembly includes a suspension and a drive assembly coupled to the opposite side of the suspension. The electric vehicle axle assembly engages with the wheels of the vehicle to rotate the wheels, thereby moving the vehicle along the ground. The drive unit transmits power to the wheels via one or more gear sets and axle shafts.

Description

[0001] Cross-referencing of relevant U.S. patent applications

[0002] This application claims priority to U.S. Provisional Application No. 62 / 812,039, filed on February 28, 2019, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] This disclosure generally relates to axle assemblies for vehicles, and more specifically, to electric axle assemblies for vehicles. Background Technology

[0004] To facilitate entry and exit, motor vehicles are desired to have a floor (chassis) as low as possible to the ground. Buses and passenger vehicles (often referred to as low-floor vehicles) are examples of vehicles that benefit from a low floor height. By minimizing the floor height, steps at the doors are eliminated, which in turn allows for easier entry and exit for vehicle passengers. Eliminating steps is particularly beneficial for passengers with disabilities and those carrying items such as strollers. Manufacturers are increasingly turning to electric and hybrid propulsion systems for low-floor vehicles to improve performance and efficiency. To make the vehicle floor as low as possible, drivetrain components are repositioned to reduce intrusion into the vehicle floor. Summary of the Invention

[0005] According to one aspect of this disclosure, the electric vehicle axle assembly may include a suspension, a first drive assembly and a second drive assembly coupled to opposite sides (opposite sides) of the suspension, a drive unit, and a transmission system. A first wheel hub may be coupled to the first drive assembly, and a second wheel hub may be coupled to the second drive assembly. The first and second wheel hubs may be arranged to support a wheel for rotation about a first axis.

[0006] In an illustrative embodiment, the drivetrain may include a first gear set disposed in a first drive assembly, a second gear set disposed in a second drive assembly, and a portal axle extending between the first and second gear sets. The first gear set may be coupled to a first hub, and the second gear set may be coupled to a second hub. The portal axle may be arranged to rotate about a second axis offset from the first axis.

[0007] In an illustrative embodiment, a drive unit may be disposed in a first drive assembly and may be configured to provide power to a differential via a first gear set. A portal shaft may be coupled to the differential. The differential may be configured to transmit power via the first gear set to a first hub and via a portal shaft and a second gear set to a second hub.

[0008] In an illustrative embodiment, the first gear set may include a differential, an end shaft (short shaft) coupled to the differential, a first output gear set coupled to the end shaft, and a first planetary gear set coupled to the first output gear set and the first hub. The differential may be arranged along a second axis. The second gear set may include a second output gear set coupled to a door shaft on the opposite side (opposite side) of the differential, and a second planetary gear set coupled to the second output gear set and the second hub.

[0009] In an illustrative embodiment, the bridge portion of the suspension may be offset from the first axis, and the door hinge may be arranged to be substantially aligned with the bridge portion.

[0010] In an illustrative embodiment, the differential may include a housing, a star gear coupled to the housing for rotation about a second axis together with the housing, and side gears coupled to the portal shaft and end shaft respectively and meshing with the star gear.

[0011] In an illustrative embodiment, the differential may include a housing, a pair of planetary gears coupled to the housing for rotation about a second axis together with the housing, and side gears coupled to a portal shaft and an end shaft, respectively. The planetary gears may mesh with each other and with corresponding side gears.

[0012] In an illustrative embodiment, the first output gear set may include a shaft gear coupled to an end shaft and an output gear coupled to a first planetary gear set and meshing with the shaft gear.

[0013] In an illustrative embodiment, the output gear may be arranged to rotate about a first axis.

[0014] In an illustrative embodiment, the first planetary gear set may include a sun gear coupled to an output gear for rotation about a first axis, planet gears arranged radially outward of the sun gear and meshing with the sun gear, a ring gear arranged radially outward of the planet gears and meshing with the planet gears, and a carrier (planet carrier) coupled to the planet gears and the first hub. The ring gear may be fixed (stationary) relative to the first axis.

[0015] In an illustrative embodiment, the second output gear set may include a shaft gear coupled to a door shaft and an output gear coupled to a second planetary gear set and meshing with the shaft gear.

[0016] In an illustrative embodiment, the output gear may be arranged to rotate about a first axis.

[0017] In an illustrative embodiment, the second planetary gear set may include a sun gear coupled to the output gear for rotation about a first axis, planet gears disposed radially outward of and meshing with the sun gear, a ring gear disposed radially outward of and meshing with the planet gears, and a carrier coupled to the planet gears and the second hub. The ring gear may be fixed relative to the first axis.

[0018] In an illustrative embodiment, the electric vehicle axle assembly may further include a drive gear coupled to a differential and arranged to receive power from a drive unit.

[0019] In an illustrative embodiment, the electric vehicle axle assembly may also include a transmission. The transmission may include a first input gear and a second input gear coupled to a drive gear, a first output gear and a second output gear rotatably mounted on a support shaft coupled to a differential, and a gear selector mounted on the support shaft. The drive gear may be arranged to receive power from a drive unit. The first input gear may mesh with the first output gear, and the second input gear may mesh with the second output gear. The gear selector may be movable along the support shaft and fixed non-rotatably relative to the support shaft. The gear selector may be configured to selectively engage either the first or second output gear to prevent rotation of the engaged first or second output gear relative to the support shaft.

[0020] In an illustrative embodiment, in a first configuration, the gear selector can engage with a first output gear to prevent rotation of the first output gear relative to the support shaft and allow rotation of the second output gear relative to the support shaft, thereby providing a low gear ratio. In a second configuration, the gear selector can engage with a second output gear to prevent rotation of the second output gear relative to the support shaft and allow rotation of the first output gear relative to the support shaft, thereby providing a high gear ratio.

[0021] In an illustrative embodiment, the electric vehicle axle assembly may also include an actuator configured to move a gear selector to first and second configurations. Attached Figure Description

[0022] The systems and methods described herein are illustrated by way of example rather than limitation in the accompanying drawings (hereinafter referred to as "Figures (singular)" or "Figures (plural)"). For the sake of simplicity and clarity, the elements shown in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to others for clarity. Furthermore, reference numerals are repeated in the figures where deemed appropriate to indicate corresponding or similar elements.

[0023] Figure 1 This is a perspective view of an electric vehicle axle assembly for a low-floor vehicle according to an embodiment of the present disclosure.

[0024] Figure 2 yes Figure 1 The front view of the electric vehicle axle assembly shown.

[0025] Figure 3 yes Figure 1 A schematic diagram of an electric vehicle axle assembly.

[0026] Figure 4 yes Figure 3 A schematic diagram of the differential of an electric vehicle axle assembly.

[0027] Figure 5 yes Figure 3 A schematic diagram of the planetary gear set of the electric vehicle axle assembly.

[0028] Figure 6 This is a schematic diagram of another electric vehicle axle assembly for a low-floor vehicle according to an embodiment of the present disclosure.

[0029] Figure 7 yes Figure 6 A schematic diagram of the differential of an electric vehicle axle assembly.

[0030] Figure 8 This is a schematic diagram of another electric vehicle axle assembly for a low-floor vehicle according to an embodiment of the present disclosure.

[0031] Figure 9 It is similar to Figure 8 The view shows the axle portion of the suspension of the electric vehicle axle assembly with a shortened width. Detailed Implementation

[0032] While the concepts of this disclosure are readily accepted in various modifications and alternatives, specific exemplary embodiments thereof have been shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that this is not intended to limit the concepts of this disclosure to the specific forms disclosed, but rather, it is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

[0033] References to "an embodiment," "an example embodiment," "an exemplary embodiment," etc., in this specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, it should be assumed that implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether or not such feature, structure, or characteristic is explicitly described in other embodiments) falls within the knowledge scope of those skilled in the art.

[0034] exist Figure 1-3An exemplary electric vehicle axle assembly 10 according to this disclosure is shown. The electric vehicle axle assembly 10 can be used, for example, in low-floor vehicles (e.g., buses) to support and propel the vehicle on the ground. The electric vehicle axle assembly 10 includes a suspension 12 and first and second drive assemblies 14, 16 coupled to opposite sides (opposite sides) of the suspension 12. The suspension 12 includes a bracket 15 and an axle portion 17. The suspension 12 is attached to a vehicle frame (not shown) via the bracket 15 and a control arm 19, thereby supporting the drive assemblies 14, 16 relative to the vehicle frame. In an illustrative embodiment, the bracket 15 is coupled to the drive assemblies 14, 16, and the drive assemblies 14, 16 are coupled to the axle portion 17 to support the drive assemblies 14, 16 spaced apart from each other. In some embodiments, the bracket 15 is coupled to the drive assemblies 14, 16, and the axle portion 17 (including a pair of guide rails arranged along opposite sides of the drive assemblies 14, 16) is coupled to the bracket 15 to support the drive assemblies 14, 16 spaced apart from each other.

[0035] The drive unit 18 (e.g., an electric motor) of the drive assembly 14 provides power to the transmission system 20, thereby enabling the wheels 100 mounted on the hubs 11, 13 to move. Figure 2 (As shown by the dashed line in the diagram) rotates about axis A in order to push the vehicle along the ground, as... Figure 1 and Figure 2 As shown. Hubs 11 and 13 allow the wheel 100 to be attached to drive assemblies 14 and 16 so that it rotates with the drivetrain 20. The drivetrain 20 includes a first gear set 22 of the first drive assembly 14, a second gear set 24 of the second drive assembly 16, and a door axle 26 coupled between the first and second gear sets 22 and 24. The door axle 26 is arranged to rotate about axis B. The axle 17 and door axle 26 are offset from the axis of rotation A of the wheel 100 to lower the height of the vehicle's low floor, as... Figure 2 As shown. Ideally, the vehicle floor should be as low as possible and as wide as possible to maximize vehicle capacity. In the illustrative embodiment, the axis of rotation B of the door axle 26 is offset by a distance D from the axis of rotation A of the wheels 100 and hubs 11, 13 along the vertical axis V. The axle 17 is also positioned as low as possible, and the door axle 26 and the axle 17 can be aligned along the horizontal plane, as... Figure 2 As shown.

[0036] The first gear set 22 is arranged to transmit the power provided by the drive unit 18 to the wheel hub 11 and the door hinge 26, such as Figure 1-3As shown. The gantry 26 transmits power from the first gear set 22 to the second gear set 24, and the second gear set 24 transmits power to the hub 13. It should be understood that the arrangement of the drive unit 18 and the transmission system 20 can be reversed (where the drive unit 18 and the first gear set 22 are located in the second drive assembly 16, and the second gear set 24 is located in the first drive assembly 14), without departing from this disclosure.

[0037] like Figure 3 As shown, the first gear set 22 includes a differential 30, a first output gear set 32, and a first planetary gear set 34. An input gear 36 coupled to the drive unit 18 meshes (engages) with a drive gear 38 coupled to the differential 30 to transmit power from the drive unit 18 to the differential 30. A portal shaft 26 and an end shaft (short shaft) 31 are coupled to the differential 30 and extend in opposite directions. The first output gear set 32 ​​is coupled to the end shaft 31, which transmits power from the differential 30 to the first output gear set 32 ​​and the first planetary gear set 34, thereby driving the hub 11 (and the attached wheel 100) to rotate. In the illustrative embodiment, the portal shaft 26, the differential 30, and the end shaft 31 are arranged along a rotation axis B to rotate about the axis B. The first output gear set 32 ​​includes a shaft gear (pinion) 33 coupled to the end shaft 31 and an output gear 35 meshing with the shaft gear 33. The output gear 35 is coupled to the planetary gear set 34, and the axle shaft 37 coupled to the planetary gear set 34 engages with the wheel hub 11.

[0038] The door hinge 26 transmits power from the differential 30 to the second gear set 24 of the second drive assembly 16 to drive the hub 13 (and the attached wheel 100) to rotate, as... Figure 3 As shown. The second gear set 24 includes a second output gear set 42 coupled to the portal shaft 26 opposite to the differential 30, and a second planetary gear set 44 coupled to the second output gear set 42. The second output gear set 42 is similar to the first output gear set 32 ​​and includes a shaft gear 43 coupled to the portal shaft 26 and an output gear 45 meshing with the shaft gear 43. The output gear 45 is coupled to the planetary gear set 44, and the axle shaft 47 coupled to the planetary gear set 44 engages with the wheel hub 13.

[0039] Differential 30 allows the door shaft 26 and end shaft 31 to rotate at different speeds relative to each other, such as Figure 3 and Figure 4 As shown. In the illustrative embodiment, the differential 30 is an "open" differential and includes a housing 50, one or more star gears 52, 54 coupled to the housing 50 for rotation with the housing 50, and side gears 56, 58 coupled to the portal shaft 26 and the end shaft 31, respectively, as shown. Figure 4As shown. Rotation of housing 50 causes star gears 52, 54 to move about axis of rotation B, and star gears 52, 54 mesh with side gears 56, 58 to cause door shaft 26 and end shaft 31 to rotate with housing 50. Star gears 52, 54 can also rotate relative to housing 50 to allow a relative difference in rotational speed between door shaft 26 and end shaft 31, thereby preventing wheels from dragging, for example, during vehicle steering.

[0040] Each of the planetary gear sets 34 and 44 can be arranged similarly, and Figure 5 The following description of the first planetary gear set 34 shown also applies to the second planetary gear set 44. The first planetary gear set 34 includes a sun gear 62 coupled to an output gear 35, one or more planetary gears 64 coupled to a carrier 66, and a fixed ring gear 68 (relative to axis A). The ring gear 68 is arranged radially outward of the planetary gears 64 (relative to axis A of rotation), and the planetary gears 64 are arranged radially outward of the sun gear 62. Rotation of the sun gear 62 with the output gear 35 moves the planetary gears 64 about axis A of rotation and rotates the carrier 66. The axle shaft 37 is coupled to the carrier 66 to rotate with the carrier 66. In the second planetary gear set 44 of the second gear set 24, the output gear 45 is coupled to the sun gear 62, and the axle shaft 47 is coupled to the carrier 66. As contemplated in this disclosure, in some embodiments, the differential 30 may be a "lock-down," "torque-biased," "limited-slip," or other type of differential.

[0041] The placement of planetary gear sets 34, 44 in drive assemblies 14, 16 allows the use of commercial off-the-shelf (COTS) hubs, which are common for smaller, low-floor vehicles, such as shuttle buses. However, it should be understood that in some embodiments, the first and second planetary gear sets 34, 44 may be coupled into hubs 11, 13, wherein axle shafts 37, 47 are coupled between output gears 35, 45 and sun gears 62 in the first and second planetary gear sets 34, 44. In some embodiments, a transfer case (reduction gearbox) may be used to help keep the door shaft 26 as low as possible. An exemplary transfer case is disclosed in U.S. Patent No. 6,964,317, issued November 15, 2005, the disclosure of which is incorporated herein by reference in its entirety.

[0042] In some embodiments, the axle portion 17 may also accommodate additional components, such as an electrical inverter device for supplying power to the drive unit 18, power communication cables, a power supply battery, cooling system components, and / or a device controller for operating the electric vehicle axle assembly 10. Examples of other axle assemblies for low-floor vehicles are shown in International Patent Application Publication No. WO2019 / 014479, published January 17, 2019, and WO2019 / 217861, published November 14, 2019, the disclosures of which are incorporated herein by reference in their entirety.

[0043] exist Figure 6 Another embodiment of the electric vehicle axle assembly 210 according to this disclosure is shown. The electric vehicle axle assembly 210 is similar to... Figure 1-5 The electric axle assembly 10 is used in this context, and similar numbers starting with 200 are used to identify similar components; the same description applies. At least one difference between electric axle assembly 210 and electric axle assembly 10 is the use of a planetary differential 230 (sometimes called a spur gear differential) instead of differential 30, such as... Figure 6 and Figure 7 As shown. The planetary differential 230 allows the portal shaft 226 and the end shaft 231 to rotate at different speeds relative to each other. In an illustrative embodiment, the planetary differential 230 includes a housing 250, one or more pairs of planetary gears 252, 254 coupled to the housing 250 for rotation with the housing 250, and side gears 256, 258 respectively coupled to the portal shaft 226 and the end shaft 231, as shown. Figure 7 As shown. Rotation of housing 250 causes planetary gears 252, 254 to move about axis of rotation B, and planetary gears 252, 254 mesh with each other and with corresponding side gears in side gears 256, 258, so that the door shaft 226 and end shaft 231 rotate with the rotation of housing 250. Planetary gears 252, 254 may also rotate relative to housing 250 to allow for a relative difference in rotational speed between door shaft 226 and end shaft 231, thereby preventing wheels from dragging, for example, during vehicle steering.

[0044] exist Figure 8 Another embodiment of the electric vehicle axle assembly 310 according to this disclosure is shown. The electric vehicle axle assembly 310 is similar to... Figure 1-5 The electric axle assembly 10 is used, and similar parts are identified by numbers beginning with 300; the same description applies. At least one difference between the electric axle assembly 310 and the electric axle assembly 10 is the use of a multi-speed transmission 370 combined with a differential 330, such as... Figure 8As shown. In the illustrative embodiment, the transmission 370 is a two-speed transmission and includes gears 372, 374, 376, 378 and a gear selector 379. A first input gear 372 and a second input gear 374 are coupled to a drive gear 338 to rotate with the drive gear 338 under the drive of a drive unit 318. A first output gear 376 and a second output gear 378 are rotatably mounted on a support shaft 373 coupled to a differential 330. The first input gear 372 meshes with the first output gear 376, and the second input gear 374 meshes with the second output gear 378. An actuator 371 is coupled to the gear selector 379 to move the gear selector 379 along the support shaft 373 relative to the first and second output gears 376, 378.

[0045] exist Figure 8 In the diagram, gear selector 379 is shown in the neutral position between the first and second output gears 376 and 378, wherein gear selector 379 is disengaged from both the first and second output gears 376 and 378 to allow the first and second output gears 376 and 378 to rotate about the rotation axis B relative to the support shaft 373. Gear selector 379 is fixed non-rotatably relative to the support shaft 373 and is configured to engage with the first and second output gears 376 and 378 by being moved by actuator 371 to prevent the first and second output gears 376 and 378 from rotating relative to the support shaft 373. In a first configuration, gear selector 379 engages with the first output gear 376 to prevent the first output gear 376 from rotating relative to the support shaft 373 and allows the second output gear 378 to rotate relative to the support shaft 373. In the second configuration, the gear selector 379 engages with the second output gear 378 to prevent the second output gear 378 from rotating relative to the support shaft 373 and to allow the first output gear 376 to rotate relative to the support shaft 373. In some embodiments, a differential 230 may be used instead of a differential 330, wherein the support shaft 373 is coupled to the differential 230.

[0046] like Figure 8As shown, for rotating the door shaft 326 and end shaft 331 via the drive unit 318, the transmission 370 provides multiple selectable gear ratios (gear ratios). For example, when the gear selector 379 is in a first configuration, the first input gear 372 and the first output gear 376 provide a first gear ratio (e.g., a low gear ratio), which allows for increased torque transmitted from the drive unit 318 to the door shaft 326 and end shaft 331 at the expense of speed, thereby allowing the vehicle to accelerate more quickly. In a second configuration, the second input gear 374 and the second output gear 378 provide a second gear ratio (e.g., a high gear ratio), which allows for increased rotational speed of the door shaft 326 and end shaft 331 at the expense of torque, thereby allowing the vehicle to reach higher speeds.

[0047] In some embodiments, the dimensions of the door hinge 326 and the bridge 317 can be adjusted to accommodate different configurations of the vehicle's low floor, such as... Figure 8 and Figure 9 As shown. For example, as Figure 8 As shown, the first and second drive components 314 and 316 can be spaced apart by a width W1 in the first configuration. Figure 9 As shown, the first and second drive assemblies 314 and 316 can be spaced apart by a width W2 in a first configuration, wherein the width W2 is smaller than the width W1. This also applies to the electric vehicle axle assemblies 10 and 210 disclosed herein.

[0048] The descriptions of various embodiments of electric vehicle axle assemblies herein can be incorporated by reference to each other.

[0049] In an illustrative embodiment, the electric vehicle axle assembly according to this disclosure can be arranged for use with a vehicle (e.g., a bus). Wheels are arranged at opposite ends of the electric vehicle axle assembly to support the vehicle for transport along the ground. The electric vehicle axle assembly propels the vehicle by transmitting power to the wheels in contact with the ground. The vehicle may include a chassis on which a body and other equipment may be supported. The chassis may include frame longitudinal beams; suspension components, such as springs, shock absorbers, and trailing arms; and braking components, such as cylinders, brake calipers, brake rotors, brake drums, brake hoses, etc. The electric vehicle axle assembly may be mounted perpendicular to the frame longitudinal beams so that the vehicle travels in a direction aligned with the frame longitudinal beams.

[0050] In illustrative embodiments, the electric axle assembly can be configured for both "single-wheel" and "two-wheel" applications. In a "single-wheel" application, a single wheel is coupled to each end of the electric axle assembly. Similarly, in a "two-wheel" application, wheels are arranged in pairs at each end of the electric axle assembly. A vehicle requiring increased payload or traction capacity is an example of a "two-wheel" application. Vehicles requiring further increased payload / traction capacity can be equipped with two or more electric axle assemblies. Some vehicles may require drive mechanisms other than wheels. For example, tracks or rail wheels can be coupled to the electric axle assembly to propel the vehicle. The electric axle assembly can be mounted at the front and rear of the vehicle to enable various drive modes such as front-wheel drive, rear-wheel drive, and all / four-wheel drive.

[0051] In the illustrative embodiment, vehicle performance is optimized when the wheels are in continuous contact with the ground. To facilitate better ground following, the suspension system can movably couple the electric axle assembly to the frame longitudinals. The suspension system allows the electric axle assembly to move relative to the frame longitudinals and pushes the wheels to the ground when the vehicle encounters a ground defect. The suspension system may include: springs and shock absorbers that absorb motion and improve ride quality; control arms that limit the movement of the electric axle assembly; and other application-dependent elements such as steering and motion linkages. The electric axle assembly can also be installed on vehicles that were not originally equipped with an electric axle assembly. The electric axle assembly can be retrofitted to these vehicles to provide an electric drivetrain upgrade.

[0052] In illustrative embodiments, the electric axle assembly can be used in hybrid electric vehicles and all-electric vehicles. In an all-electric vehicle, the electricity supplying the electric axle assembly can be stored in a battery mounted on the chassis. Alternatively, electricity can be supplied from an external power source (e.g., overhead power lines or a third rail system). If the vehicle is configured as a hybrid electric vehicle, the internal combustion engine can be mounted to the chassis and coupled to a drive unit capable of generating electricity; the electricity can directly power the electric axle assembly or can be stored in the battery.

[0053] In an illustrative embodiment, the electric vehicle axle assembly may include a drive housing (sometimes referred to as a housing) that houses at least one drive unit and drives a gear train (sometimes referred to as a transmission). The drive unit is coupled to the drive housing and engages with the gear train to transmit power to the wheels. The gear train may include a series of gears and shafts supported on the electric vehicle axle assembly for rotation on the electric vehicle axle assembly. Typically, bearings are used to reduce friction between rotating components in the gear train. Depending on the application requirements, various bearing types may be used, such as journal (sliding) bearings, roller bearings, ball bearings, etc. Friction is further reduced by using lubricants, for example, by supplying oil to the contact surfaces between components such as gear teeth and bearings to prevent wear and reduce heat. The electric vehicle axle assembly may also include two wheel ends (sometimes referred to as wheel hubs). It should be understood that the drive housing and wheel ends can be constructed and coupled in various ways. The electric vehicle axle assembly may be configured for low-floor buses and includes multiple drive housings, wherein each drive housing is arranged on opposite sides of the electric vehicle axle assembly. Fasteners, etc., may be used to assemble the drive housings.

[0054] In illustrative embodiments, the electric axle assembly includes a drive unit (e.g., an electric motor) combined with a single-speed or two-speed transmission configuration to provide starting and speed performance. Furthermore, the electric axle assembly includes an axle housing that compactly integrates the electric motor and transmission, providing cooling for heat dissipation and transferring vehicle loads to suspension components. The electric axle assembly can also be installed on vehicles not originally equipped with an electric axle assembly and can be retrofitted to these vehicles to provide an electric drivetrain upgrade. For example, a low-floor bus originally equipped with a conventional axle assembly can use the electric axle assembly to replace the conventional axle assembly.

[0055] In an illustrative embodiment, the electric vehicle axle assembly includes a drivetrain (sometimes referred to as a reduction gear assembly) driven by a single drive unit, and an axle housing surrounding the reduction gear assembly and the single drive unit. The single drive unit drives wheels (sometimes referred to as wheel assemblies) coupled to the electric vehicle axle assembly. The reduction gear assembly includes a first gear set, a second gear set, and a portal axle shaft coupled between the first and second gear sets. The first gear set is coupled to a first axle shaft oriented along a first axis of rotation. The second gear set is coupled to a second axle shaft oriented along a second axis of rotation, wherein the first and second axle shafts extend in opposite directions. The first axle shaft is coupled to a first wheel end (sometimes referred to as a hub), and the second axle shaft is coupled to a second wheel end. The first and second wheel ends may have any design or configuration, such as COTS wheel ends, and are coupled to the respective wheel assemblies. The first and second axle shafts are coaxially oriented such that the first and second axle shafts are oriented along the same axis of rotation. In some embodiments, the first axle shaft may be offset from the second axle shaft such that the first axis of rotation is offset radially from the second axle shaft.

[0056] In the illustrative embodiment, the axle housing includes a first outer unit (sometimes referred to as a drive assembly), a second outer unit, and an axle portion. The first and second outer units are typically illustrated as having a rectangular configuration, but they can have any suitable design or configuration to accommodate the associated components discussed herein. The first and second outer units can also have different configurations than each other.

[0057] In an illustrative embodiment, a first outer unit surrounds a single drive unit and a first gear set, wherein a first axle shaft and a portal axle are partially disposed within the first outer unit. A second outer unit surrounds a second gear set, wherein a second axle shaft and a portal axle are partially disposed within the second outer unit. The bridge portion is coupled between the first and second outer units and surrounds a portion of a portal axle extending between the first and second gear sets. In some embodiments, the bridge portion may also accommodate additional components, such as an electrical inverter device for powering the drive unit, electrical communication cables, a power supply battery, and / or a device controller for operating the electric vehicle axle assembly. The outer units may be arranged at opposite ends of the bridge portion and may be laterally spaced from each other relative to the vehicle. The electric vehicle axle assembly can be attached to the vehicle and / or suspension arms using brackets, the suspension arms being coupled to the brackets to movably attach the electric vehicle axle assembly to the vehicle.

[0058] In an illustrative embodiment, the portal axle extends along a third axis of rotation that is offset from the first and second axle axles by a distance along a vertical axis. The portal axle extends through or around the axle housing between opposing outer units. Each outer unit has a width that can be reduced to increase the width of the vehicle's low floor. The bridge portion can be integrally formed with the outer unit or can be coupled to the outer unit, for example, by fasteners. For example, the bridge portion can be welded, pressed, or bolted to the outer unit.

[0059] In an illustrative embodiment, the first gear set includes an input gear, a differential gear set, a first output gear set, and a first planetary gear set. The input gear is driven by a single drive unit. The differential gear set is coupled to and driven by the input gear to transmit rotational torque from the single drive unit to the portal axle shaft and the first output gear set, thus eliminating the need for planetary gear sets at the wheel ends. For example, in some embodiments, the input gear may be coupled to a ring gear of the differential gear set. The first output gear set includes an output shaft coupled to and driven by the differential gear set. The output shaft includes a shaft gear coupled to an output gear that drives the first planetary gear set. In one embodiment, the first planetary gear set may include a planetary gear shaft coupled to the output gear at one end of a planetary gear shaft and a sun gear coupled to the other end of the planetary gear shaft. In the illustrated embodiment, the first axle shaft is coupled to the first planetary gear set and the first wheel assembly to transmit rotational torque from the single drive unit to the first wheel assembly via the differential gear set, the first output gear set, and the first planetary gear set.

[0060] In an illustrative embodiment, the differential gear set may include a planetary differential, wherein the portal axle shaft and the output shaft are coupled to the planetary differential. In other embodiments, the reduction assembly may include portal axles with different shaft lengths to accommodate the width of the axle, which may reduce the width of the axle to increase the width of the vehicle's low floor.

[0061] In an illustrative embodiment, the second gear set includes a second output gear set and a second planetary gear set. The second output gear set is coupled to the portal axle shaft and the second planetary gear set to transmit rotational torque from the portal axle shaft to the second planetary gear set, thus eliminating the need for planetary gear sets at the wheel ends. For example, in one embodiment, the second output gear set may include a second output gear coupled to a shaft gear of the portal axle shaft. The second planetary gear set may include a second planetary gear shaft coupled to the second output gear at one end of a second planetary gear shaft and a second sun gear coupled to the other end of the second planetary gear shaft. The second axle shaft is coupled to the second planetary gear set and the second wheel assembly to transmit rotational torque from a single drive unit to the second wheel assembly via the differential gear set, portal axle shaft, second output gear set, and second planetary gear set.

[0062] In illustrative embodiments, the reduction assembly may include one or more transfer cases. For example, the reduction assembly may include a transfer case coupled between the portal axle and the second planetary gear set. One or more transfer cases may have a single transfer mechanism, which may be a gear reduction or a 1:1 transfer mechanism. In some embodiments, the reduction assembly does not include a gear reduction across the portal axle. In another embodiment, the reduction assembly may include one or more transfer cases with different transfer mechanisms, wherein a first transfer case has a single-gear transfer mechanism, and a second transfer case has a dual-gear transfer mechanism. The transfer cases may have the same or different gear reduction mechanisms.

[0063] In the illustrative embodiment, the reduction assembly includes a two-speed transmission configuration to provide starting performance and speed performance. For example, the first gear set may include a transmission mechanism coupled between an input gear and a differential gear set, and selectively switchable between a first gear ratio and a second gear ratio to change the rotational torque transmitted to the first and second axle shafts. The transmission mechanism includes a reduction gear set driven by the input gear and an output gear set driven by the reduction gear set. The reduction gear set includes an input reduction gear coupled to the input gear, a first reduction gear, and a second reduction gear. The output gear set is coupled to the differential gear set and includes an output shaft, a first output gear, and a second output gear. The output shaft is coupled to the differential gear set to transmit rotational torque from the reduction gear set to the differential gear set. Both output gears are rotatably supported on the output shaft. The first output gear is coupled to the first reduction gear and corresponds to a first gear ratio of the reduction assembly, and the second output gear is coupled to the second reduction gear and corresponds to a second gear ratio of the reduction assembly. In the illustrated embodiment, each output gear is freely rotatable on the output shaft such that no torque is transmitted between the output shaft and the output gear when the corresponding gear ratio is not engaged. In one embodiment, the output shaft is oriented coaxially with the gate bridge shaft and may include an inner surface defining an aperture sized and shaped to receive the gate bridge shaft passing through it.

[0064] In an illustrative embodiment, a shift mechanism (sometimes referred to as a gear selector) is positioned between a first output gear and a second output gear and is configured to selectively engage both the first and second output gears. Each output gear may include a splined portion that engages with the shift mechanism to rotatably couple the output gear to an output shaft. The shift mechanism may include a shift sleeve, a shift fork, and an actuator. The shift sleeve is coupled to the output shaft such that the shift sleeve and the output shaft rotate at the same speed. The shift fork is operatively coupled to the actuator and the shift sleeve such that movement of the actuator causes the shift fork to slide along the output shaft onto the shift sleeve. The shift sleeve may selectively engage with the first and second output gears to place the reduction assembly in a first gear ratio or a second gear ratio, respectively. The shift sleeve and the output gear include a mating engagement feature that, when engaged, non-rotatably couples the output gear to the output shaft. The engagement feature may include a spline, a claw clutch, or a synchronizer to assist in shifting. Furthermore, the shift fork and shift sleeve can be moved to the neutral position, in which the output gear is not engaged with the shift sleeve. The actuator can be controlled manually or automatically. The actuator can respond to hydraulic, pneumatic, or electronic signals generated by a control module. Alternatively, the actuator may include a mechanical linkage controlled by an operator.

[0065] Although the present disclosure has been illustrated and described in detail in the accompanying drawings and the foregoing description, such illustrations and descriptions are to be considered exemplary rather than limiting, and it should be understood that merely illustrative embodiments have been shown and described and that protection is intended for all variations and modifications falling within the spirit of the present disclosure.

Claims

1. An electric vehicle axle assembly, comprising: Suspension, which includes the axle section; First drive component and second drive component; A first hub coupled to the first drive assembly and a second hub coupled to the second drive assembly, the first hub and the second hub being arranged to support a wheel for rotation about a first axis, wherein the first drive assembly and the second drive assembly are respectively coupled to opposite sides of the suspension along the first axis; The drive unit arranged in the first drive assembly; and The transmission system includes: A first gear set arranged in the first drive assembly, the first gear set including a differential arranged along a second axis, an end shaft coupled to the differential, a first output gear set coupled to the end shaft, and a first planetary gear set coupled to the first output gear set and the first hub; A second gear set disposed in the second drive assembly, the second gear set including a second output gear set and a second planetary gear set coupled to the second output gear set and the second hub; and A portal shaft extending between the first gear set and the second gear set, the portal shaft being coupled to the differential and arranged to rotate about a second axis offset from the first axis; In this configuration, the second output gear set is coupled to the portal axle on the opposite side of the differential, the drive unit is configured to provide power to the differential, and the portal axle is configured to transmit power from the differential to the second output gear set. The second drive assembly does not have a drive unit or a differential, such that both the first and second wheel hubs are configured to be driven solely by power generated by the drive unit arranged in the first drive assembly. The bridge portion extends between the first drive assembly and the second drive assembly, the bridge portion is offset from the first axis, and the bridge portion and the door hinge are aligned with each other along the horizontal plane and spaced apart from each other along the horizontal plane.

2. The electric vehicle axle assembly according to claim 1, wherein, The differential includes a housing, a star gear coupled to the housing for rotating together with the housing about a second axis, and side gears coupled to the portal shaft and the end shaft and meshing with the star gear.

3. The electric vehicle axle assembly according to claim 1, wherein, The differential includes a housing, a pair of planetary gears coupled to the housing for rotation about a second axis together with the housing, and side gears coupled to the portal shaft and the end shaft respectively, wherein the planetary gears mesh with each other and with a corresponding side gear among the side gears.

4. The electric vehicle axle assembly according to claim 1, wherein, The first output gear set includes a shaft gear coupled to the end shaft and an output gear coupled to the first planetary gear set and meshing with the shaft gear.

5. The electric vehicle axle assembly according to claim 4, wherein, The output gear is arranged to rotate about the first axis.

6. The electric vehicle axle assembly according to claim 4, wherein, The first planetary gear set includes a sun gear coupled to the output gear for rotation about the first axis, planet gears arranged radially outward of the sun gear and meshing with the sun gear, a ring gear arranged radially outward of the planet gears and meshing with the planet gears, and a carrier coupled to the planet gears and the first hub, wherein the ring gear is fixed relative to the first axis.

7. The electric vehicle axle assembly according to claim 1, wherein, The second output gear set includes a shaft gear coupled to the door shaft and an output gear coupled to the second planetary gear set and meshing with the shaft gear.

8. The electric vehicle axle assembly according to claim 7, wherein, The output gear is arranged to rotate about the first axis.

9. The electric vehicle axle assembly according to claim 7, wherein, The second planetary gear set includes a sun gear coupled to the output gear for rotation about the first axis, planet gears arranged radially outward of the sun gear and meshing with the sun gear, a ring gear arranged radially outward of the planet gear and meshing with the planet gear, and a carrier coupled to the planet gears and the second hub, wherein the ring gear is fixed relative to the first axis.

10. The electric vehicle axle assembly of claim 1, further comprising a drive gear coupled to the differential and arranged to receive power from the drive unit.

11. The electric vehicle axle assembly of claim 1, further comprising a transmission, the transmission comprising: A first input gear and a second input gear are coupled to a drive gear, the drive gear being arranged to receive power from the drive unit; A first output gear and a second output gear are rotatably mounted on a support shaft coupled to the differential, wherein the first input gear meshes with the first output gear and the second input gear meshes with the second output gear; and A gear selector mounted on the support shaft, the gear selector being movable along the support shaft and fixed relative to the support shaft without relative rotation. The gear selector is configured to selectively engage with the first output gear or the second output gear to prevent the engaged first output gear or the second output gear from rotating relative to the support shaft.

12. The electric vehicle axle assembly according to claim 11, wherein: In the first configuration, the gear selector engages with the first output gear to prevent the first output gear from rotating relative to the support shaft and to allow the second output gear to rotate relative to the support shaft, thereby providing a low gear ratio; and In the second configuration, the gear selector engages with the second output gear to prevent the second output gear from rotating relative to the support shaft and to allow the first output gear to rotate relative to the support shaft, thereby providing a high gear ratio.

13. The electric vehicle axle assembly of claim 12, further comprising an actuator configured to move the gear selector to the first configuration and the second configuration.

14. An electric vehicle axle assembly, comprising: Suspension, which includes the axle section; First drive component and second drive component; A first hub coupled to the first drive assembly and a second hub coupled to the second drive assembly, the first hub and the second hub being arranged to support a wheel for rotation about a first axis, wherein the first drive assembly and the second drive assembly are respectively coupled to opposite sides of the suspension along the first axis; The drive unit arranged in the first drive assembly; and The transmission system includes: A first gear set disposed in the first drive assembly and coupled to the first hub; The second gear set is arranged in the second drive assembly and coupled to the second hub; and A door hinge arranged to rotate about a second axis offset from the first axis, the door hinge extending between the first gear set and the second gear set; In this configuration, the drive unit is configured to provide power to the differential of the first gear set, the portal shaft is coupled to the differential, and the differential is configured to transmit power through the first gear set to the first wheel hub and through the portal shaft and the second gear set to the second wheel hub. The second drive assembly does not have a drive unit or a differential, such that both the first and second wheel hubs are configured to be driven solely by the power generated by the drive unit arranged in the first drive assembly. The bridge portion extends between the first drive assembly and the second drive assembly, the bridge portion is offset from the first axis, and the bridge portion and the door hinge are aligned with each other along the horizontal plane and spaced apart from each other along the horizontal plane.

15. The electric vehicle axle assembly according to claim 14, wherein, The differential is arranged along the second axis so as to rotate about the second axis.

16. The electric vehicle axle assembly of claim 14, further comprising a drive gear coupled to the differential and arranged to receive power from the drive unit.

17. The electric vehicle axle assembly of claim 14, further comprising a transmission, the transmission comprising: A first input gear and a second input gear are coupled to a drive gear, the drive gear being arranged to receive power from the drive unit; A first output gear and a second output gear are rotatably mounted on a support shaft coupled to the differential, wherein the first input gear meshes with the first output gear and the second input gear meshes with the second output gear; and A gear selector mounted on the support shaft, the gear selector being movable along the support shaft and fixed relative to the support shaft without relative rotation. The gear selector is configured to selectively engage with the first output gear or the second output gear to prevent the engaged first output gear or the second output gear from rotating relative to the support shaft.

18. The electric vehicle axle assembly according to claim 17, wherein: In the first configuration, the gear selector engages with the first output gear to prevent the first output gear from rotating relative to the support shaft and to allow the second output gear to rotate relative to the support shaft, thereby providing a low gear ratio; and In the second configuration, the gear selector engages with the second output gear to prevent the second output gear from rotating relative to the support shaft and to allow the first output gear to rotate relative to the support shaft, thereby providing a high gear ratio.

19. The electric vehicle axle assembly of claim 18, further comprising an actuator configured to move the gear selector to the first configuration and the second configuration.

Images