WORK VEHICLE WITH ELECTRIC DRIVE AXLES

Abstract

A work vehicle contains front and rear electric drive axles mounted to its chassis. Each electric drive axle has an axle housing that defines chassis mounts configured to attach to the chassis. The axle housing defines an internal cavity located between opposing ends that define openings. Wheel bearing units are at least partially mounted within the axle housing. Each wheel bearing unit defines a hub that engages with a ground-contacting element of the work vehicle through an associated opening. Each wheel bearing unit has drive components configured to rotate the hub of each wheel bearing unit. A battery pack is mounted within the axle housing between the wheel bearing units.A power control device is mounted inside the axle housing between the wheel bearing units. The power control device is electrically coupled to the wheel bearing units and the battery pack and is configured to control the power supply from the battery pack to the wheel bearing units. A drive component is mounted outside the axle housings of the front and rear electric drive axles on the chassis and is coupled to the power control device of each of the front and rear electric drive axles to supply power to or receive power from the front and rear electric drive axles.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] Not applicable. DECLARATION ON GOVERNMENTALLY FUNDED RESEARCH OR DEVELOPMENT

[0002] Not applicable. AREA OF REVELATION

[0003] This disclosure relates generally to work vehicles and, more particularly, to electric drives for work vehicles. BACKGROUND OF REVELATION

[0004] Work vehicles, such as those used in agriculture, construction, forestry, and mining, typically require high-torque drivetrains to provide high tractive effort for off-road driving and to power heavy work equipment. Large fuel combustion engines (e.g., diesel engines) are the traditional powerplants for such heavy work vehicles. Advancing technology has led to the integration of electric drivetrains into work vehicles in conjunction with, or as a replacement for, conventional engines. Such electrified work vehicles can feature entirely redesigned platforms (e.g., chassis, etc.) for the arrangement of work vehicle components and subsystems. SUMMARY OF REVELATION

[0005] The present disclosure provides a work vehicle with electric drive axles.

[0006] Specifically, a work vehicle includes a chassis supported on the ground by ground-engaging members, and front and rear electric drive axles attached to the chassis. Each of the front and rear electric drive axles includes an axle housing defining chassis mounts configured to be attached to the chassis, the axle housing defining an internal cavity disposed between opposite ends defining openings; wheel bearing assemblies at least partially mounted within the axle housing, each wheel bearing assemblies defining a hub for engaging one of the ground-engaging members through an associated one of the openings, each wheel bearing assemblies having drive components configured to rotate the hub of each wheel bearing assemblies; a battery pack mounted within the axle housing between the wheel bearing assemblies;and a control device mounted within the axle housing between the wheel bearing units, the control device being electrically coupled to the wheel bearing units and the battery pack and configured to control the power supply from the battery pack to the wheel bearing units. A drive component is mounted to the chassis outside the axle housings of the front and rear electric drive axles and coupled to the power control device of each of the front and rear electric drive axles to supply power to or receive power from the front and rear electric drive axles.

[0007] In one embodiment of the work vehicle, each power control device is coupled to a DC bus interface and configured to charge the associated battery pack with the power received via the DC bus interface.

[0008] In other embodiments, each of the wheel bearing units includes an electric machine coupled to the associated control device, each control device configured to control the supply of power from the associated battery pack to the associated electric machine in each of the wheel bearing units. Each electric drive axle further includes an inverter mounted within the associated axle housing. Each power control device is configured to control the conversion of direct current from the associated battery pack to alternating current supplied to the electric machines of the associated wheel bearing units.

[0009] In other embodiments, the drive component is one or more of an additional battery pack, a brake regenerative unit, a generator, a charging interface, or a traction control unit.

[0010] Other embodiments of the work vehicle further include steering mechanisms in the axle housings, and each of the wheel bearing assemblies is secured to the associated axle housings by the associated steering mechanisms. Structural chassis mounts may be configured to support the axle housing, battery pack, power control device, or wheel bearing assemblies of each of the front and rear electric drive axles and couple them to the chassis of the work vehicle.

[0011] In other embodiments, conduits are included in the axle housing and configured to convey coolant to and from the battery packs, the wheel bearing assemblies, or the power control device. For example, each of the front and rear electric drive axles may include: an inlet and an inlet manifold within the associated axle housing coupled to the associated battery pack and the power control device; an outlet and an outlet manifold within the associated axle housing coupled to the associated battery pack and the power control device; a bypass passage within the associated axle housing and coupling the associated inlet manifold and outlet manifold; and a bypass valve within the associated axle housing configured to control flow through the associated bypass passage.In some cases, the associated power control device is configured to change a state of the associated bypass valve to allow flow from the associated outlet manifold through the associated inlet channel to the associated inlet manifold when the temperature of the associated battery pack falls below a threshold battery operating temperature.

[0012] The details of one or more embodiments are set forth in the accompanying drawings and the following description. Further features and advantages will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a side view of an exemplary work vehicle having the electric drive axle according to the present disclosure; Fig. 2 is a schematic diagram of the underside of the work vehicle according to an exemplary embodiment; Fig. 3A is a schematic diagram of an electric drive axle according to an exemplary embodiment; Fig. 3B is a schematic diagram of an electric drive axle with integrated structural support according to an exemplary embodiment; Fig. 4A is a schematic diagram of a multi-axle electric powertrain including the electric drive axle according to an exemplary embodiment; Fig. 4B is a schematic diagram of a multi-axle electric powertrain including the electric drive axle according to another exemplary embodiment; Fig. 5 is a schematic diagram of an electric drive axle and cooling system according to an exemplary embodiment; Fig. 6 is a schematic diagram of a control system for an electric drive axle according to an exemplary embodiment; and Fig. 7A-7C are views of an exemplary wheel bearing assembly for an electric drive axle according to the present disclosure.

[0013] In the various drawings, like reference numerals indicate like elements. DETAILED DESCRIPTION

[0014] One or more exemplary embodiments of an electric drive axle and a work vehicle are described below, as illustrated in the accompanying figures of the drawings briefly described above. Various modifications of the exemplary embodiments are contemplated by those skilled in the art. The disclosed electric drive axle and work vehicle are suitable for use in or as vehicles in agriculture, construction, forestry, mining, and other work areas. OVERVIEW

[0015] Large work vehicles, such as those used in agriculture, construction, forestry, and mining, require large powertrains to provide traction for off-road travel and power implements needed for heavy-duty work. Until now, internal combustion engines, such as diesel engines, have been the primary power source for such work vehicles. To reduce emissions, modern work vehicles are being electrified. This typically requires a completely redesigned vehicle platform to optimize the arrangement of vehicle subsystems on the chassis, which can be complex and costly.

[0016] To solve these problems, one aspect of this disclosure provides a self-contained electric drive axle with wheel drives, with motors and reduction gears, battery packs, and power electronics that either: (a) fit within the axle housing of existing vehicle platforms, or (b) are mounted on the chassis in place of existing axle assemblies. The electric drive axle may include structural components in the form of discrete spacers that attach the internal components of the electric drive axle either directly to the chassis or to an external axle housing that is otherwise coupled to the chassis. In the latter case, the electric drive axle may have an inner housing that houses the internal components and that fits within the outer axle housing but does not provide structural support for the internal components.Alternatively, the electric drive axle may include a structural axle housing that serves to secure the electric drive axle to the chassis and provide structural support for its internal components. The term "structural" herein means that the axle housing or chassis mounts are designed to withstand and transmit forces sufficient to connect the ground-contacting elements of the work vehicle to the chassis via the wheel drives within the electric drive axle, allowing the ground-contacting elements to support the chassis on the ground.

[0017] Another aspect of this disclosure is that vehicle components, such as the transmission and motor, can be replaced with components coupled to the electric drive axle, such as additional battery packs, regenerative brakes, traction control units, and / or generators. In this way, a wide range of vehicle platforms can be converted to an electric drivetrain by simply replacing one, two, or more axle housings and possibly installing other components in the vacant positions of the omitted components and / or a traction control unit. The electrical connection of these additional components can be achieved via a robust DC bus system.

[0018] Another aspect of the disclosure is that the electric drive axle may be equipped with internal components for cooling and heating or an interface for connecting to an external on-board thermal management system. In various embodiments, the electric drive axle includes a coolant circuit having an inlet, an outlet, and conduits or channels within the axle housing configured to conduct coolant from the inlet to the battery pack and power control device, and from the battery pack and power control device to the outlet. An inlet manifold and an outlet manifold may be disposed within the axle housing and coupled to the respective inlet and outlet, as well as to the battery pack and power control device.

[0019] In some cases, a bypass line or channel may be disposed within the axle housing, coupling the inlet manifold to the outlet manifold. The electric drive axle may include one or more valves in the coolant circuit. For example, a bypass valve may control flow through the bypass line or channel. The power control device may be configured to change the state of the bypass valve depending on a prescribed temperature, temperature range, or temperature threshold. For example, the power control device may be configured to close the bypass valve to prevent flow from the outlet manifold to the inlet manifold when the battery pack falls below a prescribed battery operating temperature range. A pump may be incorporated into the axle housing and configured to generate flow through the bypass line or channel.The power control device may be coupled to the pump and configured to activate the pump when the temperature of the battery pack falls below the operating temperature range of the battery. The power control device may also be configured to change the state of the bypass valve to prevent flow through the bypass channel and deactivate the pump when the temperature of the battery pack exceeds the operating temperature range of the battery.

[0020] In other embodiments, the electric drive axle may include a plurality of valves positioned within the axle housing to control flow from the intake manifold to individual components within the axle housing. For example, the electric drive axle may include a first valve for controlling flow from the intake manifold to the battery pack and a second valve for controlling flow from the intake manifold to the power control device. The power control device may be coupled to the first valve and the second valve and configured to control the first valve in response to the temperature of the battery pack and the second valve in response to the temperature of the power control device.

[0021] In other embodiments, the coolant circuit may be configured to deliver coolant from the inlet to the wheel bearing units and from the wheel bearing units to the outlet. Each of the wheel bearing units may define an oil circulation path configured for heat exchange with the cooling circuit. In some cases, the electric drive axle may include a heat exchanger external to the axle housing, with the inlet and outlet coupled to the heat exchanger. A pump inside or outside the axle housing may be configured to effect the flow of coolant through the heat exchanger and the pipes or channels within the axle housing.

[0022] In various other embodiments, one or more inverters may be mounted with the axle housing, with the power control device configured to control the conversion of direct current from the battery pack to alternating current supplied to the wheel bearing units. The power control device may be coupled to a DC bus interface configured to charge the battery pack with the power received via the DC bus interface. A battery management system may be incorporated into the axle housing and configured to control the charging and discharging of the battery pack.

[0023] The power control device may be equipped with control logic for intelligently controlling cooling by the electric drive axle. Various control algorithms may be used to optimize the cooling of one or more components in the axle housing. Although various control logic may be used, one example of control logic prevents coolant from flowing through the coolant circuit during cold start of the vehicle, but allows heat flow from the electric machines of the wheel bearing units. In other examples, the coolant circuit may direct coolant to the battery pack upon reaching a temperature threshold and continue to cool the battery pack beyond a prescribed temperature range or maximum temperature value. When the inverters, e.g.When the inverters, such as an IGBT inverter and a SIC inverter, reach one or more prescribed temperature values, coolant can flow to the inverters and further cool the inverters over one or more prescribed temperature ranges or maximum temperature values. When the electric machines and transmissions reach one or more prescribed temperature values, coolant can flow to the wheel bearing units and further cool the electric machines and wheel bearing units over one or more prescribed temperature ranges or maximum temperature values. The algorithm can supply coolant with the same or different temperature ranges and values ​​to the various components of the electric drive axle.For example, the battery pack can be cooled to a target temperature that is lower than a target temperature of the IGBT inverter, which is lower than a target temperature of the electrical machines in the wheel bearing unit, which is lower than a target temperature of the SIC inverter. The target temperature for cooling the gears of the wheel bearing units can extend over a temperature range that includes the target temperatures of the battery pack, the inverters, and the electrical machines. EXAMPLE ELECTRIC DRIVE AXLE(S) FOR WORK VEHICLES

[0024] As in Fig. 1, a work vehicle 100 may be used as an agricultural tractor or other heavy work vehicle such as those used in agriculture, construction, forestry, and mining. The work vehicle 100 includes a chassis 102 upon which a plurality of ground-engaging elements 104, such as wheels or the depicted tracks, are mounted to support the chassis 102 on the ground. An engine housing 106 may be supported by the chassis 102 and may contain an internal combustion engine, such as a diesel engine. An operator's cab 108 may also be supported by the chassis 102, in which an operator of the work vehicle 100 may be seated. It should be understood that the present disclosure may also apply to autonomous work vehicles, in which case the operator's cab may be omitted.

[0025] Referring to Fig. 2, the work vehicle 100 may include a pair of ground-contacting members 104 coupled to a common axle 110 in an axle housing 200 having openings 200a at opposite lateral ends of the work vehicle 100 that provide access for coupling the axle 110 to the pair of ground-contacting members 104. The work vehicle 100 may define a longitudinal direction, which is defined as the direction of travel of the work vehicle 100 when traveling in a straight line on a level surface. The transverse direction may be defined as perpendicular to the longitudinal direction and to a vertical direction, the vertical direction being parallel to the direction of gravity when the work vehicle 100 is on a level surface.

[0026] The axle housing 200 may span the chassis 102 in a lateral direction, with a rotational axis of the axle 110 within the axle housing 200 substantially (e.g., within 5 degrees) parallel to the lateral direction. The axle housing 200 is structurally coupled to the chassis 102 at a plurality of chassis mounts 202 by permanently attached (e.g., welded) or removable fasteners (e.g., bolts or other tool-removable fasteners). The axle housing 200 may extend laterally outward from the chassis and extend into a hub of the ground-engaging members 104 on either side of the chassis 102. The depicted work vehicle 100 includes two axle housings 200 and four ground-engaging members 104.In alternative examples, multiple axles and axle housings may be mounted on the front of the work vehicle and multiple axles and axle housings may be mounted on the rear of the work vehicle. A corresponding number of ground-contacting elements may be used.

[0027] The axle housing 200 may include substantially cylindrical (e.g., all points within 0.1R of a cylinder of radius R) sections and various non-cylindrical features 200b. For example, a portion of the axle housing 200 near the center of the axle housing 200 may bulge outward to accommodate certain internal components, such as a differential or other transmission. The axle housing 200 may have widened end portions to accommodate a reduction gear that couples an axle to the ground-contacting members 104. The chassis 102 to which the axle housing 200 is attached therefore accommodates such non-cylindrical features. The axle housing 200 defines an interior volume 204 that provides a cylindrical and / or non-cylindrical space for receiving the axle 110 and other axle components housed therein.

[0028] The work vehicle 100 may further include internal cavities or spaces that would typically accommodate a transmission (not shown), such as space 206, an internal combustion engine (not shown), such as space 208 occupied by a transmission. Other cavities and spaces may also be provided, such as those typically occupied by a fuel tank (not shown). In some cases, the electric drive axle may be retrofitted to existing conventional work vehicles, and in other cases, the electric drive axle may be incorporated as part of the original manufacturing process.In both cases, the electric drive axle may be installed in the work vehicle chassis, either in existing axle housings used in conventional body styles or in structural axle housings specifically designed for the electric drive axle and fitting in the same footprint as the conventional axles it replaces. Furthermore, during retrofitting and original manufacturing, the work vehicle platform may be modified from conventional platforms by removing the internal combustion engine, transmission, and other components such as fuel components (e.g., tank, pumps, hoses, and the like). In cases where a gas generator is used, as discussed below, the original fuel system may be retained or replaced with other (e.g., less absorbent) fuel components.Other components can also be removed, replaced, or repurposed, such as certain cooling components (e.g., radiator, coolant pump, fan).

[0029] Fig. 3A is a schematic diagram of an electric drive axle 300 that may be used in place of an axle in the work vehicle 100. The electric drive axle 300 may be sized and configured to be mounted in an axle housing 200 of the work vehicle 100, either with or without modification, and either with or without removal and reinstallation of the axle housing 200 during installation of the electric drive axle 300. The axle housing 200 may be modified to include one or more openings for receiving various operating conduits (e.g., electrical conduits and wires, hydraulic or coolant hoses, etc.), but may otherwise remain unchanged. The axle housing 200 may therefore continue to be used as the axle housing of the electric drive axle 300.

[0030] The exemplary electric drive axle 300 includes one or more battery packs 302. The battery packs 302 may be embodied, for example, as lithium-ion battery packs. The battery packs 302 may include both battery cells and associated circuitry for supplying power to the battery cells. The battery packs 302 may include temperature sensors and channels for flowing coolant through the battery packs 302. The battery packs 302 may include a battery management system or circuitry for connecting to a battery management system. The battery packs 302 are sized to fit within the interior volume 204 of the axle housing 200 and may therefore have a cylindrical shape or conform to another shape, such as the shape of the interior of a differential housing.

[0031] The electric drive axle 300 contains a power electronics 304. The power electronics are described with reference to Fig. 6 and includes circuitry for managing the power supply to and from the battery packs 302, managing the temperature of the battery packs 302, supplying power from the battery packs 302 to the wheel bearing units 308, and receiving the power generated by the wheel bearing units 308. The power electronics 304 may include temperature sensors and possibly channels for passing coolant through the power electronics 304. The power supply to the components 302, 304, 308 of the electric drive axle 300 may be controlled by the power electronics 304.

[0032] Each wheel bearing unit 308 includes an electric machine 309 and a reduction gear 311 for driving the ground-contacting elements 104, as well as an interface (e.g., a hub) to which the ground-contacting elements 104 can be attached. The reduction gear may have a single gear or may include a multi-gear transmission with selectable gears, e.g., two or more gears. The wheel bearing unit 308 may be implemented using concepts described in some or all of the following patents, all of which are incorporated herein by reference in their entirety: U.S. Patent Nos. 10,214,101, 10,107,363, and 10,207,580.

[0033] The axle housing 200 may include one or more structural supports 306 integrated as a single piece or attached thereto. The structural supports 306 provide attachment points for the wheel bearing assemblies 308 that are sufficiently strong to support the portion of the weight of the work vehicle 100 transferred to the associated ground-contacting member 104 attached to each wheel bearing assembly 308. The structural supports 306 also provide attachment points for coupling the wheel bearing assemblies 308 to the axle housing 200 or the chassis 102 of the work vehicle 100, or both, that are also sufficiently strong to support the portion of the weight of the work vehicle 100 transferred to the associated ground-contacting member 104 attached to the wheel bearing assembly 308. These structural supports 306 may be in addition to the chassis supports 202 or may take the form of chassis supports.

[0034] When the ground-engaging member 104 attached to the wheel drive 308 is steered, the electric drive axle 300 may include a steering mechanism, such as a steering knuckle and a control arm for engaging a steering actuator, each of which may form or supplement the structural supports 306. In some implementations, traction steering (i.e., "skid steering") may be accomplished by selecting different speeds for the right and left sides of the work vehicle 100, in which case no steering mechanism is included in the electric drive axles 300.

[0035] In certain exemplary embodiments, the electric drive axle 300 may include a housing 310 disposed within the axle housing 200. The housing 310 may provide protection from dirt and abrasion, but otherwise does not provide substantial structural strength to the electric drive axle 300 and may therefore be considered "non-structural." The wheel bearing assemblies 308 may be located entirely within the housing 310 or partially within the housing 310, such that portions of the wheel bearing assemblies 308 extend outwardly from the housing 310 and the axle housing 200.

[0036] With reference to Fig. 3B, the electric drive axle 300 may alternatively include an outer housing or structural support 312 that may be attached to the chassis 102 of a work vehicle 100 in place of the axle housing 200 without requiring modification of the chassis 102. The outer structural support 312 may be a hollow structure that provides an axle housing for the components 302, 304, 306, 308 of the electric drive axle 300 while providing sufficient structural support to transfer the weight of the work vehicle 100 to the wheel bearing assemblies 308, either directly or via steering mechanisms 314. This outer housing or structural support 312 may be in addition to the chassis mounts 202 or may take the form of these mounts.The structural support 312 may have an outer surface that conforms to the surfaces of the axle housing 200 that are coupled to the chassis 102, including the chassis mounts 202. For example, the structural support 312 may have one or more enlarged volume areas (e.g., corresponding to a differential or reduction gear) to utilize the space available within the chassis 102. The surfaces of the structural support 312 that do not contact the chassis 102 may be different from the axle housing 200 that the structural support 312 replaces, if necessary to ensure adequate ground clearance. Accordingly, the structural support 312 may have a longitudinal size relative to the size of the axle housing 200 to accommodate additional or larger battery packs 302 than could fit within the axle housing 200.For example, the structural support 312 may be one to ten times larger in the longitudinal direction than the axle housing 200 replaced by the electric drive axle 300. Likewise, the volume within the structural support 312 may be one to ten times larger than the volume within the axle housing 200.

[0037] As in Fig. 4A, the work vehicle 100 may include an axle system 400 with two or more electric drive axles 300. Each electric drive axle may be identical or differ in one or more respects, including the drive components and the housings and support members for the drive components. This axle system 400 may include one or more additional battery packs 402 to supplement the capacity of the battery packs 302 of the electric drive axles 300. The axle system 400 may also include a charging interface 404 defining a receptacle and circuitry for connection to a charging station or an electrical grid. The one or more additional battery packs 402 and the charging interface 404 may be installed in one or both of the open volumes 206, 208 or in other cavities between the structural elements of the work vehicle chassis, for example, in a cavity for a fuel tank.

[0038] The battery packs 402 and the charging interface 404 may be coupled to a DC bus 410. The DC bus 410 may consist of electrical wires or busbars capable of conducting high currents and voltages, e.g., at least 30-90 amperes and at least 400-800 volts. The power electronics 304 of the electric drive axles 300 may be coupled to the same DC bus 410 or to separate DC buses 410.

[0039] In various embodiments, the power electronics 304 of the electric drive axles 300 may be coupled to a traction control unit (TCU) 406. The TCU 406 may include logic for maintaining traction and stability of the work vehicle 100 off-road during transport and work. The TCU 406 may further control the selection between multiple gears provided by the wheel bearing assemblies 308 based on driving commands, such as acceleration and braking commands, and based on the current speed of the work vehicle 100. The TCU 406 may sense the current state of the work vehicle 100 using an accelerometer, feedback from the power electronics 304, or another source.For example, the torque at each ground-contacting element 104 may be measured using a torque sensor or by measuring the current drawn by the electric machines 309 of the wheel bearing assemblies 308 coupled thereto. The torque, along with the velocity sensed by the accelerometer or the rotational speed of the electric machines 309, may be used by the TCU 406 to select the current supplied to each wheel bearing assemblies 308 of each electric drive axle 300 to avoid loss of traction due to spinning of a ground-contacting element 104 relative to the ground, to maintain stability, to steer the work vehicle 100, or to perform other operational tasks.

[0040] The axle system 400 may also include a cooling system 408 in various embodiments. An example of a cooling system 408 is described below with reference to Fig. 6. The cooling system 408 may include a heat exchanger (e.g., a radiator). The heat exchanger may be mounted in the same location as a conventional radiator used to cool an internal combustion engine. The coolant from the cooling system 408 may be used to cool some or all of the battery packs 302, the power electronics 304, and the wheel bearing assemblies 308.

[0041] With reference to Fig. 4B, in other embodiments, the open volumes 206, 208 or other cavities in the chassis of the work vehicle 102 created by the elimination of an internal combustion engine, such as a cavity occupied by a fuel tank, may additionally or alternatively accommodate components other than an additional battery pack 402 and a charger interface 404. For example, a brake regenerative unit 412 may be incorporated. A brake regenerative unit receives the power output from the electric machines 309 of the wheel bearing units 308 when the electric machines 309 act as generators, e.g., during coasting or when descending an incline. The brake regenerative unit 412 adds resistance to the current path, thereby opposing the flow of current and increasing the resistance to movement of the motor.The brake regenerative unit 412 may include fins, passages for the flow of cooling medium from the cooling system 408, or other structures for dissipating the heat generated by the resistance. The brake regenerative unit 412 may receive power from the wheel bearing units 308 via the DC bus 410. The power received from the electric machines 309 of the wheel bearing units 308 via the DC bus 410 may additionally or alternatively be used to charge the battery packs 302 of the electric drive axle 300 and supplied via the DC bus 410 for regenerative charging of the battery pack 402. For example, the generated power may be used to charge the battery packs 302, 402 without a braking command from the operator of the work vehicle 100. The generated power may additionally be supplied to the brake regenerative unit 412 in response to a braking command from the operator of the work vehicle 100.

[0042] In some embodiments, a small engine and generator 414 may be installed. The engine and generator 414 are small compared to a main propulsion engine, which is replaced by the electric drive axles 300. The engine and generator 414 may generate electricity to increase the range of the work vehicle 100. A corresponding fuel tank may be coupled to the engine and generator 414 to supply fuel to the engine and generator 414. The fuel tank may be a dedicated fuel tank (with a smaller capacity) or a primary fuel tank (with a larger capacity) such as is commonly used to fuel a main propulsion engine.

[0043] The battery packs 302 operate best within a prescribed operating temperature range. Below this prescribed operating temperature range, the battery packs 302 may lose capacity, and above this operating temperature range, the battery packs 302 may also lose capacity and become burn hazards. Other components, such as the power electronics 304 and the wheel bearing assemblies 308, generate heat that may be dissipated by the electric drive axle 300 to prevent overheating.

[0044] In various embodiments according to Fig. 5, the electric drive axle 300 may include structures for cooling and heating. For example, the electric drive axle 300 may include piping or channels for conducting coolant from an inlet to some or all of the battery packs 302, the power electronics 304, and the wheel bearing units 308, and for conducting coolant from some or all of the battery packs 302, the power electronics 304, and the wheel bearing units 308 to an outlet.

[0045] In the illustrated example, the electric drive axle 300 may include an inlet manifold 500 and an outlet manifold 502 in fluid communication with an inlet 504 and an outlet 506, respectively. The inlet 504 and the outlet 506 are in fluid communication with the cooling system 408, e.g., via separate piping (e.g., rigid conduits, flexible hoses, etc.) or via passages molded into the wall structure of the axle housing 200 or the support structure 312. Such passages may form a serpentine, zigzag, or back-and-forth pattern and may be machined, cast, or otherwise formed into the surface or interior of the housing walls. Various couplings and fittings may be mounted to the axle housing 200 or the structural support 312 to enable connection to the piping. The cooling system 408 includes a heat exchanger 508, which may be a dedicated cooler with a compact form factor.Alternatively, the heat exchanger 508 may be the same radiator used to cool an internal combustion engine previously mounted in the volume 208 and may be mounted in the same location, and the fans that direct air over the radiator to cool the internal combustion engine may be used to direct air over the heat exchanger 508 in the same manner.

[0046] The cooling system 408 may include additional components inside or outside the axle housing 200 of the electric drive axle 300, such as a pump 510 and a reservoir 512 for receiving coolant. The reservoir 512 may be coupled to the outlet 506 to receive the coolant flowing back from the electric drive axle 300, and the pump 510 may be coupled to the inlet 504. The pump 510 draws coolant from the reservoir 512 through the heat exchanger 508 and forces the coolant into the electric drive axle 300. Although in Fig. While a single electric drive axle 300 is shown in Figure 5, two, three, or more electric drive axles 300 may be coupled to the pump 510 and the reservoir 512. The coolant may be water, propylene glycol, or another cooling medium.

[0047] The pump 510 may be mounted directly to the axle housing 200 or to the chassis 102 of the work vehicle 100. The pump 510 may be the same pump used to pump coolant through the internal combustion engine being replaced by the one or more electric drive axles 300. Alternatively, the pump 510 may be a dedicated pump for the electric drive axles 300, which is likely to have a lower capacity and lower cost than the pumps used in conventional internal combustion engine applications. However, the pump 510 may be mounted in the same location and have the same hole pattern or other mounting structures as the replaced pump for attaching to the chassis 102 of the work vehicle 100.

[0048] The cooling system 408 may be controlled by the power electronics 304 or independently of the power electronics 304. For example, the power electronics 304 may activate the pump 510 based on the temperatures of one or more components 302, 304, 308. Alternatively, a separate controller may activate the pump 510 based on a measured fluid pressure in the cooling system 408. For example, a controller may be configured to activate the pump 510 to maintain a pressure at the axle assembly inlet 504 within a predefined range independent of the power electronics 304 or any other controller within the electric drive axle 300.

[0049] In some situations, the battery packs 302 may be below the operating temperature range of the battery packs and need to be warmed. In some embodiments, the heat from the power electronics 304 or the wheel bearing units 308 is used to warm the battery packs 302. For this purpose, a bypass path 514 may be provided within the electric drive axle 300 between the inlet manifold 500 and the outlet manifold 502. In this way, the coolant can circulate inside the electric drive axle 300, bypassing the cooling system 408, until cooling of the battery packs 302 is required.

[0050] To control the bypass circulation of the coolant, a bypass arrangement 516 may be used. The bypass arrangement 516 may include a bypass pump 518 and a bypass valve 520a. The bypass valve 520a has a bypass state in which an outlet of the bypass pump 518 is coupled to the inlet manifold 500, and the inlet manifold 500 is partially or completely isolated from the inlet 504. The inlet of the bypass pump is coupled to the bypass path 514, such that the bypass pump 518 draws coolant from the outlet manifold 502 through the bypass path 514 and forces the coolant into the inlet manifold 500. The circulation of the coolant removes heat from the power electronics 304 and the wheel bearing units 308, and the heated coolant heats the battery packs 302.

[0051] When cooling of some or all of the battery packs 302, the power electronics 304, and the wheel bearing assemblies 308 is required, the bypass pump 518 may be deactivated and the bypass valve 520a placed in a non-bypass state in which the bypass valve 520a couples the inlet manifold 500 to the inlet 504 with less resistance compared to the bypass state, so that the inlet manifold receives more coolant from the cooling system 408 compared to the bypass state.

[0052] In some embodiments, a second bypass valve 520b may be used. In the bypass state, the bypass valve 520b partially or completely disconnects the outlet manifold 502 from the outlet 506. In the non-bypass state, the bypass valve 520b couples the outlet manifold 502 to the outlet 506 and allows fluid to exit into the cooling system 408 with less resistance than in the bypass state.

[0053] In some embodiments, the valves 520a, 520b only switch between the bypass and non-bypass states. In other embodiments, the valves 520a, 520b may also be in intermediate states between the bypass and non-bypass states. For example, the bypass valves 520a, 520b may be placed in a bypass state that completely isolates the inlet and outlet manifolds 500, 502 from the cooling system 408 when the temperatures of the battery packs 302 are below the operating temperature range of the battery packs. When the temperatures are within the operating temperature range of the battery packs, the bypass valves 520a, 520b may be in an intermediate state in which the resistance to flow through the inlet 504 and the outlet 506 decreases with increasing temperature.When the temperatures of the battery packs 302 reach the upper end of the operating temperature range of the battery packs or a threshold below the upper end of the operating temperature range of the battery packs, the bypass valves 520a, 520b may be placed in the non-bypass state, which has the least resistance to flow through the inlet 504 and the outlet 506 and the greatest resistance to flow through the bypass path 514 (e.g., the complete interruption of flow) for a predefined range of operating states of the bypass valves 520a, 520b.

[0054] The pump 518 may also operate only in a bypass state (on) and a non-bypass state (off), or in intermediate states between the bypass state and the non-bypass state. The electrical current supplied to the pump 518 may be supplied at a rate inversely proportional to the battery temperature until the valves 520a, 520b are placed in the non-bypass state, in which the pump 518 is turned off.

[0055] It should be noted that in some embodiments, the pump 518 may be omitted. For example, the proximity of the battery packs 302 to the power electronics 304 and the wheel bearing units 308 may be sufficient to heat the battery packs 302 to such an extent that only one or two valves 520a, 520b separate them from the cooling system 408.

[0056] Each of the battery packs 302 may define a coolant path coupled to the inlet manifold 500 and the outlet manifold 502. The coolant path may run between the cells of the battery pack 302 or extend externally around the cells. The power electronics 304 also defines a coolant path coupled to the inlet manifold 500 and the outlet manifold 502. As shown in Fig. 7A-7C below, the wheel bearing units 308 may also define a coolant path that extends through or over the wheel bearing units 308 and is coupled to the inlet manifold 500 and the outlet manifold 502. In some embodiments, the wheel bearing unit 308 includes an oil circulation path 522 through which the lubricating oil circulates. The circulation of the oil may be accomplished by means of an electric pump or a mechanical pumping mechanism. A heat exchanger 524 may be coupled to the oil circulation path 522 to transfer heat between the coolant and the oil circulation path. The heat exchanger 524 may have an inlet coupled to the inlet manifold 500 and an outlet coupled to the outlet manifold 502.

[0057] The amount of coolant flowing through each of the battery packs 302, the power electronics 304, and the wheel bearing assemblies 308 may be controlled by one or more valves 526. For example, the valves 526 may control the fluid flow through one or more components and open proportionally to the temperatures of the one or more components. The valves 526 may be electrically controlled valves controlled by the logic of the power electronics 304 or another component. In the illustrated embodiment, a plurality of dedicated valves 526 control the flow of coolant through the battery packs 302, the power electronics, and the wheel bearing assemblies 308. However, other arrangements are possible. For example, the battery packs 302 may operate at approximately the same load, so that a single valve 526 controls the coolant flow to multiple battery packs 302.

[0058] The operation of the valves 526 may depend on whether the valves 520a, 520b are in a bypass or non-bypass state. In the non-bypass state, each valve 526 may limit the flow of coolant through one or more components when the temperature of the one or more components is below a temperature threshold defined for the one or more components. However, if heating of the battery packs 302 is required, the valves 526 may be opened as far as possible to allow free circulation of the fluid to absorb heat from the power electronics 304 and the wheel bearing units 308, even when the temperatures of the power electronics 304 and the wheel bearing units 308 are below the respective temperature thresholds.

[0059] Fig. 6 shows an example of a control system 600 for the electric drive axle 300. The power electronics 304 may include circuitry, computing capacity, or other components for controlling the operation of the electric drive axle 300. However, the functionality attributed here to the power electronics 304 may also be performed by one or more other components. The power electronics 304 may be coupled to the bypass pump 518 and supply power to the bypass pump 518 as described above. The power electronics 304 may be coupled to the valves 602 (e.g., some or all of the valves 520a, 520b, 526). The power electronics 304 may be coupled to various vehicle sensors (e.g., speed, acceleration, pressure, temperature, etc.), such as: B. with the temperature sensors 604 of some or all of the battery packs 302, the power electronics 304 itself and the wheel bearing units 308.

[0060] The power electronics 304 may define interfaces, such as a TCU interface 610 for connecting to the TCU 406. Other components, such as the bypass pump 518, the valves 602, the temperature sensors 604, the battery packs 302, and the controls, may communicate with the power electronics 304 via a data bus interface 612, such as a Controller Area Network (CAN) bus, an Onboard Diagnostics (OBD) bus, or another type of bus or network communication protocol, and the associated electronic components. The power electronics 304 may include a power control device 614. The power control device 614 may include a computing device configured to process inputs from sensors, such as a temperature sensor 612, and a power controller 614. B. temperature sensors 604, inputs from the TCU 406 and operator inputs received via the controls 608 and to control the operation of the electric drive axle 300 accordingly.For example, the power controller 614 may receive the outputs of the temperature sensors 604 and control the operation of the bypass pump 518 and the valves 602 according to the outputs of the temperature sensors 604, as described above with reference to FIG. Fig. 5. In another example, power controller 614 receives outputs from controls 608 that command acceleration, deceleration, turning, or other actions. Power controller 614 controls the power supplied to or generated by wheel bearing units 308 to implement the operator's commands, either alone or in cooperation with TCU 406, to prevent wheel roll and spin.

[0061] The controls 608 may be coupled to the data bus interface 612. The controls 608 may be configured, prior to converting the work vehicle 100 to electric propulsion, to send messages on the data bus in response to changes in the state of the controls 608 (e.g., a state of an accelerator pedal, a state of a brake pedal, and a steering angle of a steering wheel). The messages may be sent directly by the controls 608 or by an electronic control unit (ECU). Accordingly, the power controller 614 may receive these messages via the data bus interface 612 and control the operation of the wheel bearing units 308 accordingly to attempt to achieve the acceleration, braking, and / or rotation commanded by a user actuating the controls 608.

[0062] In still other embodiments, the battery packs 302 may provide battery charge information to the power controller 614. The battery charge information may indicate the current flowing into or out of the battery pack 302 and the voltage supplied by or to the battery pack 302. The battery charge information may further include the output of one or more temperature sensors 604 of the battery pack 302. The power controller 614 may provide the battery charge information to a battery management system (BMS) 616. The BMS 616 then controls the current supplied to each battery pack 302 during charging or the current drawn from each battery pack 302 during use to extend the useful life of each battery pack 302 and prevent unsafe operation of each battery pack 302.In some embodiments, each battery pack 302 may include its own BMS, such that the power electronics 304 does not include the BMS 616.

[0063] The power electronics 304 may include one or more inverters 618, such as an insulated gate bipolar transistor (IGBT) inverter and a silicon carbide (SiC) inverter. The inverter 618 converts direct current to alternating current, which is supplied to the wheel bearing assemblies 308 via an output port 620. The inverter 618 receives direct current from the battery packs 302 via an input port 622. The inverter 618 may include or be coupled to an interface 624 to the DC bus 410 to receive direct current from the battery pack 402, the charger interface 404, and / or the motor and generator 414. The current generated by the wheel bearing units 308 during braking or rolling can be converted to direct current and transmitted by the inverter 618 via the input port 622 to the battery packs 302 and / or via the interface 624 to the DC bus 410 to charge the battery pack 402.

[0064] As described above, the power electronics 304 can control the opening of the valves 526 depending on the temperatures detected by the temperature sensors 604. In certain embodiments, the power control device 614 can execute control algorithms with logic that defines a predetermined pattern for various operating states of the work vehicle 100 and temperature states of one or more components of the electric drive axle 300. The power control device 614 can execute control algorithms with logic that supplies the various components of the electric drive axle 300 with coolant at the same or different temperature ranges and values.For example, the battery packs 302 can be cooled to a target temperature value that is lower than a target temperature value of the IGBT inverter, which is lower than a target temperature value of the electric machines in the wheel bearing unit, which is lower than a target temperature value of the SIC inverter. The target temperature for cooling the gear reductions 311 of the wheel bearing units 308 can comprise a temperature range that includes the target temperatures of the battery packs 302, the inverter 618, and the electric machines 309.

[0065] An example of a control scheme is as follows. A cold start of the work vehicle 100 may be defined as starting the work vehicle 100 after it has not been operated for a prescribed period of time (e.g., about 8 hours), or when the ambient temperature (or the temperature of a component (e.g., the battery)) is below a threshold temperature (e.g., less than about 10°C), or both. During a cold start event, the power control device 614 may control the cooling system to open the bypass and prevent cooling of the battery packs 302. Depending on the conditions, the power control device 614 enables passive heating by the wheel drive units 308 or, if necessary, engages an additional heat source. Upon reaching a temperature threshold (e.g., about 25°C), the coolant circuit may supply coolant to the battery packs 302 and heat the battery pack 302 for a prescribed temperature range (e.g.,approximately 10-35°C) or a maximum temperature value. When the inverters 618 reach one or more prescribed temperature values, coolant may flow to the inverters and further cool the inverters over one or more prescribed temperature ranges or maximum temperature values. For example, an IGBT inverter may be cooled at and between approximately 50-60°C and a SiC inverter may be cooled at and between approximately 80-90°C. When the electric machines 309 and the gear reductions 311 of the wheel bearing units 308 reach one or more prescribed temperature values, coolant may flow to the wheel bearing units and further cool the electric machines and gears over one or more prescribed temperature ranges or maximum temperature values. For example, the electric machines 309 may be cooled at and between approximately 65-75°C and the gear reductions 311 may be cooled at and between approximately 40-90°C.

[0066] Fig.7A-7C show one embodiment of a heat exchanger 524 for a wheel bearing assembly 308. The wheel bearing assembly 308 may include a motor housing 700 housing an electric machine 309 (e.g., a motor / generator) and a transmission housing 702 housing a reduction gear 311. The wheel bearing assembly 308 may define an axial direction, which is defined as a line substantially parallel (e.g., within two degrees) to an axis about which a wheel driven by the wheel bearing assembly 308 rotates. A radial direction may be defined as a movement or orientation that passes through the axial direction and is perpendicular to the axial direction in a plane that includes the axial direction. A circumferential direction may be defined as a curve or surface centered on the axial direction or tangent to a circle centered on the axial direction.

[0067] The motor housing 700 defines a coolant path 704. The coolant path 704 may be milled, cast, or otherwise formed into the motor housing 700 itself, or may be formed in a sleeve 706 secured around the motor housing 700. The outer surface of the sleeve 706 or the motor housing 700 may correspond to an axially centered cylinder. The coolant path may include an inlet region 708a and an outlet region 708b, each of which may be formed as a recess defined in the cylindrical outer surface and are coupled to each other only by the coolant path 704 extending between the inlet region 708a and the outlet region 708b.In the illustrated embodiment, the coolant path 704 includes outwardly leading portions 710 that extend outwardly from the inlet region 708a and extend circumferentially around the motor housing 700 to a point offset between 150 and 180 degrees from the inlet region 708a.

[0068] In the illustrated embodiment, the outward-leading sections 710 have a shape that can be described, in whole or in part, as serpentine, zigzag, or reciprocating. Stated differently, the circumferential length of the fluid path defined by each outward-leading section 710 can be between two and fifteen times the length of the outer surface of the sleeve 706 in which the outward-leading section 710 is formed. The shape of the outward-leading sections 710 increases the area of ​​the sleeve 706 that contacts the coolant and increases the time it takes for the coolant to travel through the coolant path 704 to increase heat transfer into the coolant. The outward-leading sections 710 can extend to a transition region 712 located at a point offset between 150 and 180 degrees from the inlet region 708a along the circumferential direction.Inwardly leading portions 714 of the coolant path 704 extend from the transition region 712 back to the outlet region 708b, which is adjacent to the inlet region 708a. For example, the outlet region 708b may be substantially aligned with the inlet region 708a along the circumferential direction (e.g., centers of both the inlet and outlet regions 708a, 708b within one and five degrees of each other along the circumferential direction). The inwardly leading portions 714 may be configured as a circumferential groove formed in the sleeve 706 that extends to the transition region 712. The transition region 712 may be configured as a groove connecting the outwardly leading portions 710 to the inwardly leading portions 714.In the illustrated embodiment, the inwardly extending portions 714 are relatively straight, for example, in the form of grooves that are substantially (e.g., within 2 degrees) parallel to the circumferential direction at all points along the inwardly extending portions 714. The inwardly extending portions 714 may be configured as a single groove that extends completely around the sleeve 706 and substantially (e.g., within 2 degrees) parallel to the circumferential direction at all points thereon. In other embodiments, the inwardly extending portions 714 may have a shape that can be described, in whole or in part, as serpentine, zigzag, or reciprocating.In other words, the circumferential length of the fluid path defined by each inwardly leading portion 714 may be between two and fifteen times the length of the outer surface of the sleeve 706 in which the outwardly leading portion 714 is formed.

[0069] The coolant may be retained in the coolant path 704 by an outer sleeve 716 secured over the sleeve 706. Gaskets, sealant, or other sealing means may be disposed between the outer sleeve 716 and the sleeve 706 to prevent coolant from leaking and possibly force the coolant to substantially (e.g., at least 90 percent of the coolant) follow the coolant path 704 between the inlet region 708a and the outlet region 708b, as defined by the inwardly leading portions 710 and the outwardly leading portions 714.

[0070] The outer sleeve 716 may define an inlet opening 718a and an outlet opening 718b aligned over the inlet region 708a and the outlet region 708b, respectively, along the circumferential and axial directions. Fluid forced into the inlet opening 718a enters the inlet region 708a and is forced along the outwardly directed portions 710, back along the inwardly directed portions 714, into the outlet region 708b, and out of the outlet opening 718b. The inlet opening 718a may be coupled to the inlet manifold 500, and the outlet opening 718b may be coupled to the outlet manifold 502, for example, using hoses and possibly interposed valves 526 to control the amount of fluid forced into the inlet opening 718a.

[0071] Various modifications may be made to the illustrated embodiment. The roles of the illustrated inlet and outlet regions 708a, 708b may be reversed so that fluid flow into the inward-facing portions 714 and back from the outward-facing portions 710. The illustrated coolant path 704 may be formed by recesses extending outward from an inner surface of the sleeve 706, while the sleeve 706 is omitted or has a smooth outer surface that cooperates with the sleeve 706. Circumferential grooves for receiving gaskets may be machined into the sleeve 706 and / or the outer sleeve 716 to facilitate sealing. An oil circulation path within the motor housing 700 may extend adjacent to or through the sleeve 706 to facilitate heat transfer. In other embodiments, cooling of the motor housing 700 is sufficient to regulate the temperature of the wheel bearing assemblies 308.

[0072] Sensors such as a temperature sensor 604, oil pressure sensor, speed sensor, or the like may be disposed in the motor housing 700 and / or the transmission housing 702 and coupled to electrical lines 720 that extend outwardly from the motor housing 700 and / or the transmission housing 702 and are coupled to the power electronics 304.

[0073] A hub 722 is attached to the transmission housing 702 and provides an attachment point for attachment to a ground-contacting element 104. The hub 722 may therefore have a pattern of bolt holes, centering structures, or other structures that enable attachment of a ground-contacting element 104 to the wheel bearing assembly 308. The hub 722 may have the same interface of bolt holes, centering structures, or other structures as the axle replaced by the electric drive axle 300, thus eliminating the need for special adapters.

[0074] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the disclosure. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms, unless the context clearly indicates otherwise. Further, it is to be understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, acts, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, acts, elements, components, and / or groups thereof.

[0075] As used herein, lists containing items separated by connectives (for example, "and") and also preceded by the phrase "one or more of" or "at least one of" indicate, unless otherwise limited or modified, configurations or arrangements that potentially include individual items of the list or any combination thereof. For example, "at least one of A, B, and C" or "one or more of A, B, and C" indicate, respectively, the possibilities of only A, only B, only C, or any combination of two or more of A, B, and C (for example, A and B; B and C; A and C; or A, B, and C).

[0076] The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limiting of the disclosure in the form disclosed. Many modifications and variations will become apparent to those skilled in the art without departing from the scope and spirit of the disclosure. Embodiments specifically set forth herein were chosen and described in order to best explain the principles of the disclosure and their practical application, and to enable others skilled in the art to understand the disclosure and to recognize many alternatives, modifications, and variations of the described example(s). Accordingly, various embodiments and implementations other than those explicitly described are within the scope of the following claims. QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] US 10,214,101

[0032] US 10,107,363

[0032] US 10,207,580

[0032]

Claims

[1] Work vehicle (100), comprising: a chassis (102) supported on the ground by ground-contacting elements (104); front and rear electric drive axles (300) attached to the chassis (102), each of the front and rear electric drive axles (300) including: an axle housing (310, 312) defining chassis mounts (202) configured to be attached to the chassis (102), the axle housing (310, 312) defining an internal cavity disposed between opposite ends defining openings (200a); Wheel bearing units (308) mounted at least partially within the axle housing (310, 312), each wheel bearing unit (308) defining a hub (722) for engagement with one of the ground-contacting elements (104) through an associated one of the openings (200a), each wheel bearing unit (308) having drive components (311) configured to rotate the hub (722) of each wheel bearing unit (308); a battery pack (302) mounted within the axle housing (310, 312) between the wheel bearing units (308); and a power control device (614) mounted within the axle housing (310, 312) between the wheel bearing units (308), the power control device (614) being electrically coupled to the wheel bearing units (308) and the battery pack (302) and configured to control the power supply from the battery pack (302) to the wheel bearing units (308); and a drive component (402, 404, 406, 412, 414) mounted on the chassis (102) outside the axle housings (310, 312) of the front and rear electric drive axles (300) and coupled to the control device (614) of each of the front and rear electric drive axles (300) to supply or receive power from the front and rear electric drive axles (300). [2] The work vehicle (100) of claim 1, wherein each power control device (614) is coupled to a DC bus interface (410) and configured to charge the associated battery pack using power received via the DC bus interface (410). [3] Work vehicle (100) according to claim 1 or 2, wherein each of the wheel bearing units (308) comprises an electric machine (309) coupled to the associated power control device (614), each power control device (614) being configured to control the power supply from the associated battery pack (302) to the associated electric machine (309) in each of the wheel bearing units (308). [4] The work vehicle (100) of claim 3, wherein each electric drive axle (300) further includes an inverter (618) mounted within the associated axle housing (310, 312), each power control device (614) configured to control the conversion of direct current from the associated battery pack (302) to alternating current supplied to the electric machines (309) of the associated wheel bearing units (308). [5] Work vehicle (100) according to one of the preceding claims, wherein the drive component is one or more of an additional battery pack (402), a brake regenerative unit (412), a generator (414), a charging interface (404) or a traction control unit (406). [6] A work vehicle (100) according to any one of the preceding claims, further comprising steering mechanisms (314) in the axle housings (310, 312), each of the wheel bearing units (308) being attached to the associated axle housings (310, 312) by the associated steering mechanisms (314). [7] A work vehicle (100) according to any one of the preceding claims, further including structural chassis mounts (306) configured to support and couple the axle housing (310), the battery pack (302), the power control device (614), or the wheel bearing units (308) of each of the front and rear electric drive axles (300) to the chassis (102) of the work vehicle (100). [8] A work vehicle (100) according to any preceding claim, further including conduits for conveying coolant in the axle housings (310, 312) to and from the battery packs (302), the wheel bearing units (308) or the power control device (614). [9] A work vehicle (100) according to any one of the preceding claims, wherein each of the front and rear electric drive axles (300) includes: an inlet (504) and an inlet manifold (500) within the associated axle housing (310, 312) and coupled to the associated battery pack (302) and the power control device (614); an outlet (506) and an outlet manifold (502) within the associated axle housing (310, 312) and coupled to the associated battery pack (302) and the power control device (614); a bypass channel (514) within the associated axle housing (310, 312) and coupling the associated inlet manifold (500) and the outlet manifold (502); and a bypass valve (520a) within the associated axle housing (310, 312) configured to control flow through the associated bypass channel (520a). [10] The work vehicle (100) of claim 9, wherein for each of the front and rear electric drive axles (300), the associated power control device (614) is configured to change a state of the associated bypass valve to allow flow from the associated outlet manifold (502) through the associated bypass channel (514) to the associated inlet manifold (500) in response to a temperature of the associated battery pack (302) falling below the threshold battery operating temperature.

Images