Systems for drive axle

Methods and systems are provided for an electric drive axle. In one example, a tube is pressed into a portion of a differential housing, wherein a mount, a reinforcement ring, a wheel hub assembly, and a brake housing are physically coupled to the tube. The tube defines an axle path of an electric drive axle from an electric motor to a wheel.

TECHNICAL FIELD

The present description relates generally to an electric drive axle for an at least partially electric vehicle.

BACKGROUND AND SUMMARY

Concern over climate change is leading manufacturers to switch energy sources from fossil fuels to other energy sources, such as electricity. This includes a variety of transportation categories including vehicles, trucks, boats, motorcycles, airplanes, trains, and other transportation devices.

Previous examples of electric axle tracks and mount fixtures may be configured to be arranged in specific vehicle arrangements. Thus, proliferation of electric vehicles may be limited due to a design of the electric axle and/or the electric motor.

Previous developments of electric axle already in market have their track and mount fixtures configured to be arranged in one specific vehicle application. Thus, proliferation of different applications for electric vehicles may be limited due to a design of the electric axle and/or the electric motor.

In one example, the issues described above may be addressed by a system for a tube pressed into a portion of a differential housing, wherein a mount, a reinforcement ring, a wheel hub, and a brake housing are physically coupled to the tube. In this way, the tubes may be shaped at different lengths based on a vehicle arrangement.

The problem described above may be further addressed in a development of a system where, the original tubes of the previous example of the electric axle are removed and replaced by new tubes in the length according to the gauge to be met, pressed together with the electric motor housing with a new support of ring of reinforcement, where it joins by friction and welds the original motor housing to the new tubes developed for the system, in addition to adapting to the length with the use of new machined tubes, it is also possible to remove the original supports and use supports as a spring, stop and suspension damper applicable to the customer's chassis. In this way, the tubes may be shaped at different lengths based on a vehicle arrangement.

As one example, the tube may define an axle track of a motor axle along with an electric motor and a differential are arranged. A differential housing may include a first portion and a second portion arranged on opposite sides of the electric motor. The first and second portions may include independent planetary gear sets arranged therein. The tube may be separated into a first tube and a second tube separated by the electric motor and the differential.

As one example, the tube may define an axle track of a motor axle along with an electric motor and a differential are arranged. A differential housing may include a first portion and a second portion arranged on opposite sides of the electric motor. The first and second portions include independent reduction gears sets arranged therein. The tubes are separated into a first tube and a second tube where by one tube is mounted with a single reducer and a tube with a reducer and the planetary differential.

DETAILED DESCRIPTION

The following description relates to a system for an electric motor. The electric motor may be included in a hybrid vehicles architecture as illustrated inFIG.1. The electric motor may comprise a rotating axis that is concentric with a wheel axis. The electric motor may be coupled with a differential and a planetary reduction gear to transfer power to a wheel hub at a desired rotation speed. A planetary gear may be arranged at each side of the electric motor within a die casted position. The planetary gear may be further configured to couple the electric motor to a drive axle. The drive axle may extend to a differential of the electric motor linked directly to the planetary gears at a first side and through a concentric axle placed inside the electric motor at a second side, opposite the first side.

Tubes and/or a housing that define an axle track may be pressed into the casted part on each of the first and second sides. One or more of mounts, brackets, a wheel hub, and brakes may be fixed on the tubes and/or the housing to provide increased flexibility to adapt the electric motor system into different vehicle applications. Various views of the example electric motor system are illustrated inFIGS.2-7.FIGS.2-7are shown approximately to scale. Alternative dimensions may be used if desired.

Turning now toFIG.1, it shows a vehicle100comprising a first shaft102and a second shaft112. The first shaft102may be configured to drive a first set of wheels104and the second shaft112may be configured to drive a second set of wheels114. In one example, the first shaft102is arranged near a front of the vehicle100and the second shaft112is arranged near a rear of the vehicle100.

A first electric motor110may be arranged on the first shaft102and a second electric motor120may be arranged on the second shaft112. The first electric motor110may be configured to drive the first shaft102, which may result in rotation of the first set of wheels104. A first battery132may be configured to supply electrical energy to the first electric motor110. The second electric motor120may be configured to drive the second shaft112, which may result in rotation of the second set of wheels114. A second battery134may be configured to supply electrical energy to the second electric motor120. In some examples, additionally or alternatively, a single battery may be configured to supply electrical energy to each of the first electric motor110and the second electric motor120.

The vehicle100is illustrated as an all-electric vehicle comprising one or more batteries for powering one or more electric motors to drive the vehicle. In one example, the vehicle100is an all-electric passenger vehicle. In some examples, additionally or alternatively, the vehicle100may be a hybrid vehicle including an engine configured to supply power to one or more of the first shaft102and the second shaft112.

FIGS.2-7illustrate various views of a drive axle, or a portion thereof, comprising an electric motor with an easy to adjust tube that defines an axle track. That is to say, the configuration of the drive axle may be modified for various vehicle configurations and packaging sizes, thereby decreasing manufacturing difficulties.FIGS.2-6may be described in tandem herein. Specifically,FIG.2shows an embodiment200illustrating a perspective view of a drive axle210.FIG.3Ashows a side-on view300of the drive axle210andFIG.3Bshows a cross-sectional view of the drive axle210.FIG.4illustrates a further embodiment400of the drive axle210.FIG.5illustrates another embodiment500of a second portion of the drive axle.FIG.6illustrates a view of the wheel hub and an interface of the drive axle.FIG.7illustrates an exploded view700of the embodiment200of the drive axle210. As such, identical components may be identically numbered inFIGS.2-7.

An axis system is shown comprising three axes, namely an x-axis parallel to a horizontal axis, a y-axis parallel to a vertical axis, and a z-axis parallel to a transverse axis and normal to each of the x- and y-axes. A direction of gravity is illustrated via an arrow292(herein, gravity292). A central axis294of the drive axle210is arranged along an x-z plane.

The drive axle210may include an electric motor250, which may be a non-limiting example of the electric motor110or the electric motor120ofFIG.1. As such, the drive axle210may be a non-limiting example of first shaft102or the second shaft112ofFIG.1. The electric motor250may be arranged centrally between a first wheel hub assembly212and a second wheel hub assembly214. The first wheel hub assembly212and the second wheel hub assembly214may be configured to mount to the first set of wheels104and the second wheel set114ofFIG.1, respectively. In one example, the first wheel hub assembly212and the second wheel hub assembly214are arranged at opposite ends of the drive axle210.

The electric motor250may be coupled to the drive axle210via a differential240and planetary reduction gears. The differential240is shown in greater detail inFIG.7. The differential240and the planetary reduction gears may be configured to supply a desired rotational speed to wheels of each of the first wheel hub assembly212and the second wheel hub assembly214.

The differential240may include a differential housing242. The differential housing242may include a first portion244and a second portion246. The differential housing may be die cast as two separate pieces, which include the first portion244and the second portion246, arranged on opposite sides of the electric motor250. In one example, the first portion244may be larger than the second portion246. Additionally or alternatively, in some examples, the first portion244and the second portion246may be equal in size. In one example, the differential240is arranged on a side of the electric motor250closer to the first wheel hub assembly212. On an opposite side of the electric motor250closer to the second wheel hub assembly212, there may be arranged another planetary gear set. That is to say, a first planetary gear set may be arranged at a first side of the electric motor250and a second planetary gear set may be arranged at a second side of the electric motor250.

The first portion244of the differential housing242may be arranged on a side of the electric motor250biased toward the first wheel hub assembly212. The second portion246of the differential housing242may be arranged on a side of the electric motor250biased toward the second wheel hub assembly214. The first portion244and the second portion246may be physically coupled to the electric motor250via a plurality of fasteners248. The plurality of fasteners248may include one or more of bolts, screws, lugs, or the like arranged around a circumference of each of the first portion244and the second portion246.

The differential housing242may include a die cast of metal, including one or more of aluminum, steel, cast iron, or the like. In one example, the differential housing242may house the differential240and the planetary gears including a first planetary gear set245within the first portion244and a second planetary gear set247within the second portion246, as shown inFIG.3C.

A first drive axle portion222(shown inFIG.3B) may extend to the differential240, where the first drive axle portion222may be engaged with the first planetary gear set245. The drive axle210may extend through the electric motor250via a concentric axle382shown inFIG.3C. A second drive axle portion224may extend into the second portion246of the differential housing242, wherein the second drive axle portion224may engage with the second planetary gear set247. In this way, the first drive axle portion222may provide a first rotational speed to the first wheel hub assembly212and the second drive axle portion224may provide a second rotational speed, different or equal to the first rotational speed, to the second wheel hub assembly214. In one example, the speeds may be differentiated via adjusting a gearing of the differential or of the planetary gear sets, which may provide torque vectoring or other all-wheel drive capabilities.

An axle track of the drive axle210may be defined via a first tube202and a second tube204. The first tube202may be pressed into the first portion244of the differential housing242. The second tube204may be pressed into the second portion246of the differential housing242. That is to say, the first tube202may be arranged at least partially inside of and in face-sharing contact with interior surfaces of the first portion244of the differential housing242. The second tube204may be pressed inside and in face-sharing contact with interior surfaces of the second portion246of the differential housing242. The drive axle210may be concentric with each of the first tube202and the second tube204about the central axis294.

The first drive axle portion222may be positioned to rotate within the first tube202. The second drive axle portion224may be positioned to rotate within the second tube204. In one example, based on a sizing of the first portion244and the second portion246of the differential housing242, lengths of the first tube202and the second tube204may be different. In one example, the length of the first tube202may be less than the length of the second tube204.

The first tube202and the second tube204may comprise a cylindrical shape. In one example, diameters of the first and second tubes202,204may be substantially identical. Additionally or alternatively, diameters of the first tube and the second tube202,204may be uniform along their lengths, measured along the central axis294.

A first reinforcement ring262may be configured to support the first tube202coupling to the first portion244of the differential housing242. The first reinforcement ring262may include a bracket263configured to couple to a portion of the first portion244of the differential housing242. A plurality of fasteners265may physically couple the first reinforcement ring262to the first portion244of the differential housing242. In one example, first reinforcement ring262comprises a trumpet or a megaphone shape. The trumpet shape may include where a first end of the ring includes a first diameter and a second end of the ring includes a second diameter, different than the first. A transition from the first diameter to the second diameter may be linear, logarithmic, exponential, or the like. The first reinforcement ring262may include a first diameter distal to the first portion244of the differential housing242. The bracket263may be coupled to the first reinforcement ring262at its first diameter. The diameter of the first reinforcement ring262may increase from the first diameter to a second diameter, wherein the second diameter of the first reinforcement ring262may be equal to a diameter of the first portion244of the differential housing242. The first tube202may extend through an opening of the first reinforcement ring262such that the first reinforcement ring262and the first tube202are concentric about the central axis294.

A second reinforcement ring266may be configured to support the second tube202coupling to the second portion246of the differential housing242. The second reinforcement ring266may include a bracket267fixedly coupled to a smaller diameter of the second reinforcement ring266. A plurality of fasteners268may physically couple the second reinforcement ring266to the second portion246of the differential housing242. In one example, second reinforcement ring266comprises a trumpet or a megaphone shape, similar to the first reinforcement ring262. The smaller diameter of the second reinforcement ring266may be distal to the second portion246. The bracket267may be coupled to the second reinforcement ring266at its smaller diameter. The diameter of the second reinforcement ring266may increase from the smaller diameter to a largest diameter, wherein the largest diameter of the second reinforcement ring266may be equal to a diameter of the second portion246of the differential housing242. The second tube204may extend through an opening of the second reinforcement ring266such that the second reinforcement ring266and the second tube204are concentric about the central axis294. In one example, the smaller diameter of the second reinforcement ring266is equal to the first diameter of the first reinforcement ring262and the largest diameter of the second reinforcement ring266is equal to the second diameter of the first reinforcement ring262. Each of the first reinforcement ring262and the second reinforcement ring266may include respective dampeners264,269.

A first mount272may be arranged on the first tube202between the first reinforcement ring262and the first wheel hub assembly212. A second mount274may be arranged on the second tube204between the second reinforcement ring266and the second wheel hub assembly214. In one example, the first mount272is adjacent to the first reinforcement ring262and the second mount274is adjacent to the second reinforcement ring266. The first mount272and the second mount274may be configured to physically couple to mounts on an underside of a vehicle. In one example, a plurality of fasteners, which may include bolts, screws, lugs, or the like, may extend into through through-holes273and275of the first and second mounts272,274, respectively, and extend into through-holes arranged on the underside of the vehicle.

The first mount272and the second mount274may include a square shape, wherein through-holes thereof may be arranged proximally to corners of the square. The first mount272may interface to the first tube202via a C-shaped interface and the second mount274may interface to the second tube204via a C-shaped interface. The C-shape interfaces may extend around a portion of a circumference of the first tube202and the second tube204.

The first tube202may be further physically coupled to each of the first wheel hub assembly212and a first brake housing213. In one example, the first brake housing213may be a disc brake housing. Turning toFIG.3B, it shows a detailed view350of the first wheel hub assembly212and the second wheel hub assembly214. The first wheel hub assembly212and the second wheel hub assembly214may be substantially identical in size and configuration.

The first wheel hub assembly212may include a first plate backing330, a plurality of fasteners332, an O-ring334, a hub body336, a disc brake338, a washer340, a nut342, an adapter344, and a plurality of bolts and washers348.

The first plate backing330may be physically coupled to the first tube202via the plurality of fasteners332. The plurality of fasteners332may extend in a direction parallel to the central axis294and away from the electric motor250. In one example, the first tube202may include an interfacing plate302with a diameter substantially equal to a diameter of the first plate backing330, wherein the diameter of the interfacing plate302may be larger than the first diameter of the first tube202.

The O-ring334may be arranged interior to the hub body336and around a body of the first drive axle portion222. The disc brake338may be arranged radially outside of the hub body336, such that the first drive axle portion, the hub body336, and the disc brake338are concentric with one another relative to the central axis294. The washer340, the nut342, and the adapter344may be configured to physically couple a rotor328of the first wheel hub assembly212to the hub body336. In one example, the adapter344may be a hub stud.

The first drive axle portion222extending into the first wheel hub assembly212comprises a flanged portion322. The flanged portion322may extend radially outward from the first drive axle portion222in a direction normal to the central axis294. The flanged portion322may interface with an inner bearing or other rotatable feature of the first wheel hub assembly212. In one example, the flanged portion322is pressed against the rotor328via the plurality of bolts and washers348.

The second wheel hub assembly214may include a first plate backing360, a plurality of fasteners362, an O-ring364, a hub body366, a disc brake368, a washer370, a nut372, an adapter374, and a plurality of bolts and washers378. The second wheel hub assembly214may be arranged identically to the first wheel hub assembly212described above.

The second drive axle portion224extending into the first wheel hub assembly212comprises a flanged portion324. The flanged portion324may extend radially outward from the second drive axle portion224in a direction normal to the central axis294. The flanged portion324may interface with an inner bearing or other rotatable feature of the second wheel hub assembly214. In one example, the flanged portion324is pressed against the rotor328via the plurality of bolts and washers348.

In this way, first tube202may be fixedly coupled to each of the first mount272, the first wheel hub assembly212, the first brake housing213, and the first reinforcement ring262. Likewise, the second tube204may be further physically coupled to each of the second wheel hub assembly214and a second brake housing215. In this way, the second tube204may be fixedly coupled to each of the second mount274, the second wheel hub assembly214, the second brake housing215, and the second reinforcement ring266.

Turning toFIG.6, it shows an alternative embodiment600of the interfacing plates302,304. In the example ofFIG.6, the interfacing plate302comprises a circular body602with an arm604extending therefrom. The circular body602may be concentric with the first drive axle portion622. The arm604may extend radially outward away from the circular body602at a location distal to the first brake housing213. The arm604may comprise a curved, half-circle shape with a long side606and a short, curved side608. A through-hole610is arranged on the arm604, wherein a fastener or other coupling device may extend through the through-hole610to physically couple the interface plate302to a portion of the first wheel hub assembly.

By shaping the first tube202and the second tube204in this way, lengths of the tubes may vary to accommodate different vehicle axle lengths and configurations. The mounts physically coupled to the tubes may be arranged along different positions of the tubes to correspond with undermount locations of an underbody of a vehicle. The brakes of the vehicle may be modified without a new die casting mold, which may save time and reduce expenses.

The disclosure also provides support for a system including a tube pressed into a portion of a differential housing, wherein a mount, a reinforcement ring, a wheel hub assembly, and a brake housing are physically coupled to the tube. In a first example of the system, the tube and the differential housing are arranged on an electric drive axle comprising an electric motor. In a second example of the system, optionally including the first example, the portion of the differential housing is a first portion arranged on a first side of the electric motor, the differential housing further comprising a second portion arranged on a second side of the electric motor opposite the first side. In a third example of the system, optionally including one or both of the first and second examples, the tube is a first tube, and where the first tube is pressed into the first portion of the differential housing, further comprising a second tube pressed into the second portion of the differential housing. In a fourth example of the system, optionally including one or more or each of the first through third examples, the first tube and the second tube are different in length. In a fifth example of the system, optionally including one or more or each of the first through fourth examples, the electric drive axle is concentric with the first tube and the second tube about a central axis.

The disclosure also provides support for a system for an electric drive axle, comprising: a differential housing comprising a first portion arranged on a first side of an electric motor and a second portion arranged on a second side of the electric motor, a first planetary gear set arranged in the first portion and a second planetary gear set arranged in the second portion, a first tube pressed into the first portion of the differential housing, and a second tube pressed into the second portion of the differential housing, wherein the first tube and the second tube are concentric with the electric drive axle relative to a central axis. In a first example of the system, the first tube is physically coupled to a first mount, a first reinforcement ring, a first wheel hub assembly, and a first brake housing, and wherein the second tube is physically coupled to a second mount, a second reinforcement ring, a second wheel hub assembly, and a second brake housing. In a second example of the system, optionally including the first example, the system further comprises: a first motor axle portion extending from the first planetary gear set to a first wheel rotor, the first motor axle portion being concentric with the first tube about a central axis. In a third example of the system, optionally including one or both of the first and second examples, the system further comprises: a second motor axle portion extending from the second planetary gear set to a second wheel rotor, the second motor axle portion being concentric with the second tube about the central axis. In a fourth example of the system, optionally including one or more or each of the first through third examples, the first motor axle portion and the second motor axle portion are linked directly to the first and second planetary gear sets and extend through a concentric axle arranged in the electric motor. In a fifth example of the system, optionally including one or more or each of the first through fourth examples, the differential housing is die cast. In a sixth example of the system, optionally including one or more or each of the first through fifth examples, the first portion of the differential housing is larger than the second portion of the differential housing. In a seventh example of the system, optionally including one or more or each of the first through sixth examples, the first portion and the second portion of the differential housing are separated by the electric motor and do not touch. In a eighth example of the system, optionally including one or more or each of the first through seventh examples, the first tube and the second tube are fixed and do not rotate.

The disclosure also provides support for a system including a differential housing comprising a first portion arranged on a first side of an electric motor and a second portion arranged on a second side of the electric motor, a first planetary gear set arranged in the first portion and a second planetary gear set arranged in the second portion, a first tube pressed into the first portion of the differential housing and physically coupled to a first mount, a first reinforcement ring, a first wheel hub assembly, and a first brake housing, and a second tube pressed into the second portion of the differential housing and physically coupled to a second mount, a second reinforcement ring, a second wheel hub assembly, and a second brake housing, wherein the first tube and the second tube are concentric with the electric drive axle relative to a central axis and, and wherein the second tube is physically coupled to a second mount, a second reinforcement ring, a second wheel hub assembly, and a second brake housing. In a first example of the system, the system further comprises: a first motor axle portion extending from the first planetary gear set to a first wheel rotor, the first motor axle portion being concentric with the first tube about a central axis. In a second example of the system, optionally including the first example, the system further comprises: a second motor axle portion extending from the second planetary gear set to a second wheel rotor, the second motor axle portion being concentric with the second tube about the central axis. In a third example of the system, optionally including one or both of the first and second examples, the first motor axle portion and the second motor axle portion are linked directly to the first and second planetary gear sets and extend through a concentric axle arranged in the electric motor. In a fourth example of the system, optionally including one or more or each of the first through third examples, the first tube and the second tube are different in length.