Patent Description:
It would be advantageous to develop an electric portal axle architecture that reduces unsprung weight, increases cost efficiency, and improves drivetrain packaging.

The present invention is defined by the independent claims and provides an electric vehicle comprising a portal axle architecture. Specifically, the electric vehicle having a frame and an axle assembly including a De Dion tube. A first wheel hub and a second wheel hub rotatably coupled with the De Dion tube. A suspension system coupled with the vehicle frame, the suspension system having at least one pair of trailing arms pivotally coupled with the vehicle frame and at least one pair of air springs.

A first electric drive assembly in driving engagement with the first wheel hub, and a second electric drive assembly in driving engagement with the second wheel hub. Particular embodiments are specified in the dependent claims.

The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter, and are illustrative of selected principles and teaching of the present disclosure. However, the drawings do not illustrate all possible implementations of the presently disclosed subject matter, and are not intended to limit the scope of the present disclosure in any way.

It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific devices, assemblies, systems and processes illustrated in the attached drawings, and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise.

Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.

Embodiments of a portal axle architecture <NUM> are described herein. In certain embodiments described herein, the portal axle architecture <NUM> is utilized with an electric bus. In addition, the portal axle architecture <NUM> may have application in both light duty and heavy duty vehicles, mass transit vehicles, commercial vehicles, off-highway vehicles, and passenger vehicles. It would be understood by a person skilled in the art that the portal axle architecture <NUM> also has industrial, locomotive, military, agricultural, and aerospace applications.

As illustrated in <FIG>, the portal axle architecture <NUM> comprises a De Dion axle assembly <NUM>, a first electric drive assembly <NUM>, and a second electric drive assembly <NUM>. A pair of wheels <NUM> are rotatably coupled with the De Dion axle assembly <NUM>. The wheels <NUM> are drivingly engaged with the first electric drive assembly <NUM> and the second electric drive assembly <NUM>, respectively. The first electric drive assembly <NUM> and the second electric drive assembly <NUM> are in electrical communication with a control system (not depicted) and a power source (not depicted). The control system may be a drive control system for the portal axle architecture <NUM>, or for the vehicle in which the portal axle architecture <NUM> is incorporated. The power source may be a battery or another source of electrical power.

The De Dion axle assembly <NUM> comprises a De Dion tube <NUM> fitted with a suspension system <NUM> and a pair of wheel hubs <NUM>. Each of the wheel hubs <NUM> is rotatably mounted on an end of the De Dion tube <NUM> and provides a mounting location for each of the wheels <NUM>. The suspension system <NUM> is a trailing arm suspension system including a first pair of trailing arms <NUM>, a second pair of trailing arms <NUM>, air springs <NUM>, and a track rod <NUM>, for example.

In an embodiment, the first trailing arms <NUM> are coupled with the De Dion axle assembly <NUM> at opposite ends thereof. The first trailing arms <NUM> may have a first end pivotally coupled with a portion (not depicted) of the De Dion axle assembly <NUM>, and a second end pivotally coupled with a portion (not depicted) of the vehicle chassis. The second trailing arms <NUM> are also coupled with the De Dion axle assembly <NUM> at opposite ends thereof. The second trailing arms <NUM> may have a first end pivotally coupled with a portion (not depicted) of the De Dion axle assembly <NUM>, and a second end pivotally coupled with a portion (not depicted) of the vehicle chassis. The first and second pairs of trailing arms <NUM>, <NUM> are disposed generally parallel with a longitudinal axis of the vehicle. The second pair of trailing arms <NUM> is disposed below the first pair of trailing arms <NUM>.

In the embodiment illustrated in <FIG>, the trailing arms <NUM>, <NUM> are generally utilized to control movement of the De Dion axle assembly <NUM> in a longitudinal direction. The track rod <NUM> is disposed generally transverse the longitudinal axis of the vehicle. The track rod <NUM> is pivotally coupled at a first end with the De Dion axle assembly <NUM>. A second end of the track rod <NUM> is pivotally coupled with the vehicle chassis. The track rod <NUM> controls the lateral movement of the De Dion axle assembly <NUM>.

The first electric drive assembly <NUM> comprises a first motor generator <NUM>, a drive shaft <NUM>, a drive pinion <NUM>, and a drive gear <NUM>. The first motor generator <NUM> is chassis mounted and an output thereof is drivingly engaged with the driveshaft <NUM>, which is in turn drivingly engaged with the drive pinion <NUM>. The drive gear <NUM> is coupled with the wheel hub <NUM>. In addition, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM>. In an embodiment, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM> via helical gearing.

The first motor generator <NUM> is in driving engagement with the driveshaft <NUM>. The first motor generator <NUM> is in electrical communication with the control system and the power source. Depending on an electrical control of the first motor generator <NUM>, the first motor generator <NUM> may apply force to propel or retard the driveshaft <NUM> and any other drivetrain components drivingly engaged therewith. Force is applied by the first motor generator <NUM> by converting electrical energy stored in the power source into kinetic energy by rotating the driveshaft <NUM> and any components drivingly engaged therewith. When the driveshaft <NUM> is retarded in response to electrical control by the control system, the first motor generator <NUM> generates electrical energy, which may be stored in the power source. An axis of the first motor generator <NUM> is generally parallel to an axis of the portal axle architecture <NUM>.

The driveshaft <NUM> is a shaft assembly utilized to transmit power to and from the first motor generator <NUM> to the drive pinion <NUM>. The drive shaft <NUM> comprises a first joint <NUM>, a shaft section <NUM>, and a second joint <NUM>. The first joint <NUM> and the second joint <NUM> are respectively drivingly engaged with the first motor generator <NUM> and the drive pinion <NUM>. As non-limiting examples, the first joint <NUM> and the second joint <NUM> may be Cardan joints, constant velocity joints, or other kinetic joints capable of transferring power to and from the first motor generator <NUM> to the drive pinion <NUM>.

The drive pinion <NUM> is a gear mounted to the second joint <NUM> of the driveshaft <NUM>. In an embodiment, the drive pinion <NUM> may be a helical gear. The drive pinion <NUM> may be supported by a portion (not depicted) of the wheel hub <NUM>. A plurality of gear teeth formed on the drive pinion <NUM> are drivingly engaged with a plurality of gear teeth formed on the drive gear <NUM>.

The drive gear <NUM> is a gear mounted to the wheel hub <NUM>. In an embodiment, the drive gear <NUM> may be a helical gear. In response to a force applied by the drive pinion <NUM>, the drive gear <NUM> applies a rotational force to the wheel hub <NUM>, and thus to the wheel <NUM>. Similarly, force may be applied to the drive pinion <NUM> through the wheel <NUM>. A gear cover (not depicted) may be coupled to the wheel hub <NUM> to enclose the drive pinion <NUM> and the drive gear <NUM>. As a non-limiting example, a drive ratio of the drive pinion <NUM> to the drive gear <NUM> may be about <NUM> to <NUM>. Further, a person having skill in the art should understand that additional reduction gearing can be added to the wheel hub <NUM> if an increased overall ratio is needed between the first motor generator <NUM> and the wheel <NUM>.

The second electric drive assembly <NUM> comprises a second motor generator <NUM>, a drive shaft <NUM>, a drive pinion <NUM>, and a drive gear <NUM>. The second motor generator <NUM> is coupled with the chassis. An output of the second motor generator <NUM> is drivingly engaged with the driveshaft <NUM>, and the driveshaft <NUM> is drivingly engaged with the drive pinion <NUM>. The drive gear <NUM> is coupled with the wheel hub <NUM>. Additionally, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM>. In an embodiment, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM> via helical gearing.

The second motor generator <NUM> is in electrical communication with the control system and the power source. Depending on an electrical control of the second motor generator <NUM>, the second motor generator <NUM> may apply a force to propel or retard the driveshaft <NUM> and any other drivetrain components drivingly engaged therewith. Force is applied by the second motor generator <NUM> by converting electrical energy stored in the power source into kinetic energy by rotating the driveshaft <NUM> and any components drivingly engaged therewith. When the driveshaft <NUM> is retarded in response to electrical control by the control system, the second motor generator <NUM> generates electrical energy, which may be stored in the power source. An axis of the second motor generator <NUM> is substantially parallel to an axis of the portal axle architecture <NUM>.

The driveshaft <NUM> is a shaft assembly utilized to transmit power to and from the second motor generator <NUM> to the drive pinion <NUM>. The drive shaft <NUM> comprises a first joint <NUM>, a shaft section <NUM>, and a second joint <NUM>. The first joint <NUM> and the second joint <NUM> are respectively drivingly engaged with the second motor generator <NUM> and the drive pinion <NUM>. As non-limiting examples, the first joint <NUM> and the second joint <NUM> may be Cardan joints, constant velocity joints, or other kinetic joints capable of transferring power to and from the second motor generator <NUM> to the drive pinion <NUM>.

The drive pinion <NUM> is a gear mounted to the second joint <NUM> of the driveshaft <NUM>. In an embodiment, the drive pinion <NUM> may be a helical gear. The drive pinion <NUM> may be supported by a portion (not depicted) of the wheel hub <NUM>. A plurality of gear teeth formed on the drive pinion <NUM> are drivingly engaged with a plurality of teeth formed on the drive gear <NUM>.

The drive gear <NUM> is a gear mounted to the wheel hub <NUM>. In an embodiment, the drive gear <NUM> may be a helical gear. In response to a force applied by the drive pinion <NUM>, the drive gear <NUM> applies a rotational force to the wheel hub <NUM> and, via the wheel hub <NUM>, to the wheel <NUM>. Similarly, force may be applied to the drive pinion <NUM> through the wheel <NUM>. A gear cover (not depicted) may be coupled to the wheel hub <NUM> to enclose the drive pinion <NUM> and the drive gear <NUM>. As a non-limiting example, a drive ratio of the drive pinion <NUM> to the drive gear <NUM> may be about <NUM> to <NUM>. Further, a person having skill in the art should understand that additional reduction gearing can be added to the wheel hub <NUM> if an increased overall ratio is desired between the second motor generator <NUM> and the wheel <NUM>.

The chassis mounted motor generators <NUM>, <NUM> reduce an unsprung weight of the portal axle architecture <NUM> as compared to an axle mounted solution. In addition, mounting the motor generators <NUM>, <NUM> on the chassis reduces the environmental impact thereon as compared to an axle mounted solution. Further, locating the motor generators <NUM>, <NUM> on the chassis increases a distance between the outboard axle components. In an embodiment where the portal axle architecture is utilized with a bus, the increased distance between the outboard axle components allows for increased passenger space. Further, the suspension system <NUM> is a parallelogram trailing arm system, which creates installation commonality with current low floor buses.

As illustrated in <FIG>, a portal axle architecture <NUM>, according to another embodiment of the presently disclosed subject matter, comprises a De Dion axle assembly <NUM>. The portal axle architecture <NUM> also comprises a first electric drive assembly <NUM>, and a second electric drive assembly <NUM>. A pair of wheels <NUM> are rotatingly mounted on the De Dion axle assembly <NUM>. The wheels <NUM> are drivingly engaged with the first electric drive assembly <NUM> and the second electric drive assembly <NUM>, respectively. The first electric drive assembly <NUM> and the second electric drive assembly <NUM> are in electrical communication with a control system (not depicted) and a power source (not depicted). The control system may be a drive control system for the portal axle architecture <NUM> or for the vehicle in which the portal axle architecture <NUM> is incorporated. The power source may be a battery or another electrical source.

The De Dion axle assembly <NUM> comprises a De Dion tube <NUM> coupled with a suspension system <NUM>. A pair of wheel hubs <NUM> are also coupled with the De Dion tube <NUM>. Each of the wheel hubs <NUM> is rotatably mounted on an end of the De Dion tube <NUM> and provides a mounting location for each of the wheels <NUM>. In the embodiment illustrated in <FIG>, the suspension system <NUM> is a trailing arm suspension system including a first pair of trailing arms <NUM>, a second pair of trailing arms <NUM>, and air springs <NUM>.

In an embodiment, the first trailing arms <NUM> are coupled with opposing ends of the De Dion axle assembly <NUM>. The first trailing arms <NUM> may have a first end pivotally coupled with a portion (not depicted) of the De Dion axle assembly <NUM>, and a second end pivotally coupled with a portion (not depicted) of the vehicle chassis. The second trailing arms <NUM> are coupled with a generally central portion of the De Dion axle assembly <NUM>. The second trailing arms <NUM> may have a first end pivotally coupled with a center portion of the De Dion axle assembly <NUM>, and a second end pivotally coupled with a portion (not depicted) of the vehicle chassis. The second trailing arms <NUM> extend outwardly from a center portion of the De Dion axle assembly <NUM> at an acute angle to the longitudinal axis of the vehicle. In addition, the second pair of trailing arms <NUM> is disposed below the first pair of trailing arms <NUM>.

The first electric drive assembly <NUM> comprises a first motor generator <NUM>, a drive shaft <NUM>, a drive pinion <NUM>, and a drive gear <NUM>. The first motor generator <NUM> is coupled with the chassis. An output of the first motor generator <NUM> is drivingly engaged with the driveshaft <NUM>. The driveshaft <NUM> is drivingly engaged with the drive pinion <NUM>. The drive gear <NUM> is coupled with the wheel hub <NUM> and is drivingly engaged with the drive pinion <NUM>. In an embodiment, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM> via spiral bevel gearing.

The first motor generator <NUM> is in electrical communication with the control system and the power source. Depending on an electrical control of the first motor generator <NUM>, the first motor generator <NUM> may apply force to propel or retard the driveshaft <NUM> and any other drivetrain components drivingly engaged therewith. The first motor generator <NUM> applies force by converting electrical energy, stored in the power source, into kinetic energy by rotating the driveshaft <NUM> and any components drivingly engaged therewith. When the driveshaft <NUM> is retarded in response to electrical control by the control system, the first motor generator <NUM> generates electrical energy, which may be stored in the power source. An axis of the first motor generator <NUM> is substantially transverse to an axis of the portal axle architecture <NUM>.

The driveshaft <NUM> is a shaft assembly utilized to transmit power between the first motor generator <NUM> and the drive pinion <NUM>. The drive shaft <NUM> comprises a first joint <NUM>, a shaft section <NUM>, and a second joint <NUM>. The first joint <NUM> and the second joint <NUM> are drivingly engaged with the first motor generator <NUM> and the drive pinion <NUM>, respectively. As non-limiting examples, the first joint <NUM> and the second joint <NUM> may be Cardan joints, constant velocity joints, or other kinetic joints capable of transferring power to and from the first motor generator <NUM> to the drive pinion <NUM>.

The drive pinion <NUM> is a gear coupled with the second joint <NUM> of the driveshaft <NUM>. In an embodiment, the drive pinion <NUM> may be a spiral bevel gear. The drive pinion <NUM> may be supported by a portion (not depicted) of the wheel hub <NUM>. A plurality of gear teeth formed on the drive pinion <NUM> are drivingly engaged with a plurality of gear teeth formed on the drive gear <NUM>.

The drive gear <NUM> is a gear mounted to the wheel hub <NUM>. The drive gear <NUM> is a spiral bevel gear. In response to a force applied by the drive pinion <NUM>, the drive gear <NUM> applies a rotational force to the wheel hub <NUM>, and to the wheel <NUM> via the wheel hub <NUM>. Similarly, force may be applied to the drive pinion <NUM> through the wheel <NUM>. A gear cover (not depicted) may be coupled with the wheel hub <NUM> to enclose the drive pinion <NUM> and the drive gear <NUM>. As a non-limiting example, a drive ratio of the drive pinion <NUM> to the drive gear <NUM> may be about <NUM> to <NUM>. Further, it should be understood by a person having skill in the art that additional reduction gearing can be added to the wheel hub <NUM> if an increased overall ratio is desired between the first motor generator <NUM> and the wheel <NUM>.

The second electric drive assembly <NUM> comprises a second motor generator <NUM>, a drive shaft <NUM>, a drive pinion <NUM>, and a drive gear <NUM>. The second motor generator <NUM> is coupled with the chassis. An output of the second motor generator <NUM> is drivingly engaged with the driveshaft <NUM>. The driveshaft <NUM> is drivingly engaged with the drive pinion <NUM>. The drive gear <NUM> is coupled with the wheel hub <NUM>. The drive gear <NUM> is drivingly engaged with the drive pinion <NUM>. In an embodiment, the drive gear <NUM> is drivingly engaged with the drive pinion <NUM> through spiral bevel gearing.

The second motor generator <NUM> is in electrical communication with the control system and the power source. Depending on an electrical control of the second motor generator <NUM>, the second motor generator <NUM> may apply force to propel or retard the driveshaft <NUM> and any other drivetrain components drivingly engaged therewith. The second motor generator <NUM> applies force by converting electrical energy, stored in the power source, into kinetic energy by rotating the driveshaft <NUM> and any components drivingly engaged therewith. When the driveshaft <NUM> is retarded in response to electrical control by the control system, the second motor generator <NUM> generates electrical energy, which may be stored in the power source. An axis of the second motor generator <NUM> is substantially transverse to an axis of the portal axle architecture <NUM>.

The driveshaft <NUM> is shaft assembly for transmitting power to and from the second motor generator <NUM> to the drive pinion <NUM>. The drive shaft <NUM> comprises a first joint <NUM>, a shaft section <NUM>, and a second joint <NUM>. The first joint <NUM> and the second joint <NUM> are drivingly engaged with the second motor generator <NUM> and the drive pinion <NUM>, respectively. As non-limiting examples, the first joint <NUM> and the second joint <NUM> may be Cardan joints, constant velocity joints, or other kinetic joints capable of transferring power to and from the second motor generator <NUM> to the drive pinion <NUM>.

The drive pinion <NUM> is a gear mounted to the second joint <NUM> of the driveshaft <NUM>. In an embodiment, the drive pinion <NUM> may be a spiral bevel gear. The drive pinion <NUM> may be supported by a portion (not depicted) of the wheel hub <NUM>. A plurality of gear teeth formed on the drive pinion <NUM> are drivingly engaged with a plurality of gear teeth formed on the drive gear <NUM>.

The drive gear <NUM> is a gear mounted to the wheel hub <NUM>. In an embodiment, the drive gear <NUM> may be a spiral bevel gear. In response to a force applied by the drive pinion <NUM>, the drive gear <NUM> applies a rotational force to the wheel hub <NUM>, and via the wheel hub <NUM> to the wheel <NUM>. Similarly, force may be applied to the drive pinion <NUM> through the wheel <NUM>. A gear cover (not depicted) may be coupled to the wheel hub <NUM> to enclose the drive pinion <NUM> and the drive gear <NUM>. As a non-limiting example, a drive ratio of the drive pinion <NUM> to the drive gear <NUM> may be about <NUM> to <NUM>. Further, it should be understood by a person having skill in the art that additional reduction gearing can be added to the wheel hub <NUM> if an increased overall ratio is required between the second motor generator <NUM> and the wheel <NUM>.

The chassis mounted motor generators <NUM>, <NUM> reduce an unsprung weight of the portal axle architecture <NUM> and create a less harsh environment for the operation of the motor generators <NUM>, <NUM> as compared to an axle mounted solution. Disposing the motor generators <NUM>, <NUM> on the chassis increases a distance between the outboard axle components. In an embodiment where the portal axle architecture <NUM> is mounted on a bus, increased distance between the outboard axle components allows for increased passenger envelope space. Further, the suspension system <NUM> is a parallelogram trailing arm system, which creates installation commonality with current low floor buses.

As illustrated in <FIG>, a portal axle architecture <NUM> has features similar to the portal axle architecture <NUM>. Features of the portal axle architecture <NUM> similar to the portal axle architecture <NUM> are similarly identified by reference numbers in series. Different and additional features of the portal axle architecture <NUM> are described intra and can be appreciated by one skilled in the art in view of <FIG> and the other embodiments of the presently disclosed subject matter illustrated and described in this disclosure.

The portal axle architecture <NUM> comprises a De Dion beam axle assembly <NUM>, a first electric drive assembly <NUM>, and a second electric drive assembly <NUM>. A pair of wheels <NUM> are rotatably coupled with the De Dion beam axle assembly <NUM>. The wheels <NUM> are drivingly engaged with the first electric drive assembly <NUM> and the second electric drive assembly <NUM>, respectively. The first electric drive assembly <NUM> and the second electric drive assembly <NUM> are in electrical communication with a control system (not depicted) and a power source (not depicted). The control system may be a drive control system for the portal axle architecture <NUM> or for the vehicle in which the portal axle architecture <NUM> is incorporated. The power source may be a battery or another electrical source.

The De Dion beam axle assembly <NUM> comprises a straight beam axle <NUM> coupled with a suspension system <NUM> and a pair of wheel hubs <NUM>. Each of the wheel hubs <NUM> is rotatably coupled with an end of the straight beam axle <NUM> and provides a mounting location for each of the wheels <NUM>. In an embodiment, the suspension system <NUM> is a trailing arm suspension system coupled with a vehicle frame <NUM>. The suspension system <NUM> includes trailing arms <NUM>, air springs <NUM>, and a track rod <NUM>. A first end of the track rod <NUM> is pivotally coupled with the De Dion beam axle assembly <NUM>, and a second end of the track rod <NUM> is pivotally coupled with the vehicle frame <NUM>.

The first electric drive assembly <NUM> and the second electric drive assembly <NUM> are respectively mounted to the trailing arms <NUM> of the suspension system <NUM>. The trailing arms <NUM> are pivotally coupled with the vehicle frame <NUM> via pivots <NUM>. The trailing arms <NUM> are disposed generally parallel to a longitudinal axis of the vehicle and extend behind the De Dion beam axle assembly <NUM>. The air springs <NUM> are coupled an upper surface of the trailing arms <NUM>, respectively.

As illustrated in <FIG>, the first and second electric drive assembly shafts <NUM>, <NUM> may be disposed through apertures in the trailing arms <NUM>, respectively. In an embodiment, the shafts <NUM>, <NUM> may be rotatably supported in the trailing arm <NUM> apertures.

<FIG> illustrate a portal axle architecture <NUM> according to another embodiment of the presently disclosed subject matter. The portal axle architecture <NUM> is a variation of the portal axle architecture <NUM>, and has similar features thereto. The embodiment of the presently disclosed subject matter shown in <FIG> includes similar components to the electric drivetrain <NUM>. Similar features of the embodiment shown in <FIG> are numbered similarly in series. Different and additional features of the embodiment shown in <FIG> are described hereinbelow and can be appreciated by one skilled in the art.

In an embodiment, the portal axle architecture <NUM> comprises a straight beam axle assembly <NUM>, a first electric drive assembly <NUM>, and a second electric drive assembly <NUM>. A pair of wheels <NUM> are rotatably coupled with the straight beam axle assembly <NUM>. The wheels <NUM> are drivingly engaged with the first electric drive assembly <NUM> and the second electric drive assembly <NUM>, respectively. The first electric drive assembly <NUM> and the second electric drive assembly <NUM> are in electrical communication with a control system (not depicted) and a power source (not depicted). The control system may be a drive control system for the portal axle architecture <NUM> or for the vehicle in which the portal axle architecture <NUM> is incorporated. The power source may be a battery or another electrical source.

The straight beam axle assembly <NUM> comprises a straight beam axle <NUM> coupled with a suspension system <NUM> and a pair of wheel hubs <NUM>. Each of the wheel hubs <NUM> is rotatably mounted on an end of the straight beam axle <NUM> and provides a mounting location for each of the wheels <NUM>. In an embodiment, the suspension system <NUM> is a trailing arm suspension system mounted to a vehicle frame <NUM> including trailing arms <NUM>, air springs <NUM>, and an axle flex beam <NUM>.

The trailing arms <NUM> are pivotally coupled with the vehicle frame <NUM>. The trailing arms <NUM> extend behind straight beam axle assembly <NUM>. The axle flex beam <NUM> is coupled with the ends of the trailing arms <NUM> which extend behind the straight beam axle assembly <NUM>. The air springs <NUM> are coupled with the trailing arms <NUM> and the axle flex beam <NUM>.

In another embodiment (not depicted), the portal axle architecture <NUM> may not include the straight beam axle assembly <NUM>. In this embodiment, the wheel hubs <NUM> are rotatably coupled with the vehicle frame <NUM>. Lateral stabilization of the vehicle frame <NUM> is controlled, at least in part, by the axle flex beam <NUM>.

As illustrated in <FIG>, the first electric drive assembly <NUM> and the second electric drive assembly <NUM>, respectively, are mounted to the trailing arms <NUM> of the suspension system <NUM>. The suspension system <NUM> provides motor generators <NUM>, <NUM> packaged on the trailing arms <NUM> close to a pivot point. The portal axle architecture <NUM> reduces an overall cost of the axle and a weight is reduced compared to current portal axle products of similar capability. Mounting the motor generators <NUM>, <NUM> on the chassis mounted trailing arms <NUM> substantially eliminates flexing of the electrical cable used with the motor generators <NUM>, <NUM> during articulation of the suspension system <NUM>. Mounting the motor generators <NUM>, <NUM> on the trailing arms <NUM> also reduces a vertical acceleration shock loading on the motor generators <NUM>, <NUM> due to road irregularities. Torque vectoring and limited slip differential functionality are possible due to the use of the motor generators <NUM>, <NUM> for each wheel when the necessary control system is utilized. In an embodiment, the portal axle architecture <NUM> can be used with single drive 4x2 buses and tandem drive 6x4 buses, such as articulated bus designs.

Other benefits of the portal axle architecture <NUM>, <NUM>, <NUM>, <NUM> can be appreciated in view of the preceding disclosure. A traditional parallelogram arm suspension or trailing arm suspension is utilized with the portal axle architecture <NUM>, <NUM>, <NUM>, <NUM> to control axle movement. Traditional outboard air springs are utilized to allow an optimal ride frequency (stiffness) versus roll stiffness.

The solid beam axle <NUM>, <NUM> having a large drop dimension, and the straight beam axle <NUM>, <NUM> are utilized to support the wheel ends. Individual outboard gear drives are utilized for each wheel <NUM>, <NUM>, <NUM>, <NUM>. Two chassis mounted motor generators <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are utilized, each one individually driving the wheel ends through the shafts <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. The shaft <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> has a similar articulation with respect to the suspension control arms allowing equal drive shaft joint angles as the suspension travels in jounce and rebound. The chassis mounted motor generators <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are rubber isolated to eliminate noise transmitted to the vehicle incorporating the portal axle architecture <NUM>, <NUM>, <NUM>, <NUM>. The outboard gear drive, service brake, air springs and wheel equipment are placed in a position as far as possible outboard to improve the passenger space between the portal axle wheel wells. In an embodiment, wide based single tires are utilized to increase an effective track width. Single reduction gearing of about <NUM>:<NUM> ratio is used with larger motors (~<NUM> - <NUM> kW each) for city bus applications. Alternately, a double reduction with two speed capability and about <NUM>:<NUM> overall ratio can be utilized to downsize the motors (~<NUM> - <NUM> kW each). A single inverter can be used to supply both motor generators due to their close proximity.

Claim 1:
An electric vehicle, comprising:
a vehicle frame;
an axle assembly including a De Dion tube (<NUM>);
a first wheel hub (<NUM>) and a second wheel hub (<NUM>) rotatably coupled with said De Dion tube (<NUM>);
a suspension system (<NUM>) coupled with said vehicle frame, said suspension system (<NUM>) comprising:
at least one pair of trailing arms (<NUM>) pivotally coupled with said vehicle frame;
a first electric drive assembly (<NUM>) in driving engagement with said first wheel hub (<NUM>); and
a second electric drive assembly (<NUM>) in driving engagement with said second wheel hub (<NUM>),
wherein said first electric drive assembly (<NUM>) comprises:
a first motor generator (<NUM>) being disposed on and thus coupled with said vehicle frame (<NUM>);
a first joint (<NUM>) coupled with said first motor generator (<NUM>);
a shaft coupled with said first joint (<NUM>);
a second joint (<NUM>) coupled with said shaft;
a pinion gear coupled with said second joint (<NUM>); and
a drive gear (<NUM>) in driving engagement with said pinion gear and coupled with said first wheel hub (<NUM>),
characterized in that
said first electric drive assembly (<NUM>) is disposed substantially transverse said axle assembly,
wherein the suspension system (<NUM>) further comprises at least one pair of air springs (<NUM>);
wherein the drive gear (<NUM>) is drivingly engaged with the pinion gear (<NUM>) via spiral bevel gearing.