Patent Description:
Motors and associated gearboxes are typically designed for specific applications. For example, gearboxes are typically designed to be used in a single motor drive unit or a dual motor drive unit, but not both. As another example, a gearbox is typically designed to be used in a particular orientation and for driving a set number of wheels. Accordingly, it would be advantageous to provide drive units that can be used for more than one application, in more than one driving mode. It would also be advantageous to provide drive units which may be independent or coupled to adapt to changing driving conditions.

<CIT> discloses a drive train of a solely electrically driven motor vehicle having two electric motors.

<CIT> discloses a transaxle and powershift method for an electric vehicle.

<CIT> discloses a drive device for a vehicle axle, in particular a rear axle.

According to a first aspect of the invention, there is provided a drive system of a vehicle including two output gears, two clutch assemblies, and a center disconnecting differential. The first output gear driven by a first motor, and the second output gear driven by a second motor. The first clutch assembly is configured to couple and decouple the first output gear from a first halfshaft connectable to a first wheel. The second clutch assembly is configured to couple and decouple the second output gear from a second halfshaft connectable to a second wheel. The center disconnecting differential is configured to couple the first output gear to the first halfshaft and to the second halfshaft.

The drive system further includes control circuitry wherein, the first clutch assembly comprises a first actuator coupled to the control circuitry, the second clutch assembly comprises a second actuator coupled to the control circuitry, and the drive system comprises a third actuator coupled to the control circuitry and configured to engage and disengage the first output gear and a differential casing. The control circuitry is configured to actuate and de-actuate each of the first actuator, the second actuator, and the third actuator. The control circuitry is configured to achieve a first drive mode wherein the first clutch assembly is engaged, the second clutch assembly is engaged, and the center disconnecting differential is disengaged. The control circuitry is configured to achieve a second drive mode wherein the first clutch assembly is engaged, the second clutch assembly is engaged, and the center disconnecting differential is engaged and configured so that the first and second halfshafts are not free to rotate independently. The control circuitry is configured to achieve a third drive mode wherein the first clutch assembly is disengaged, the second clutch assembly is disengaged, and the center disconnecting differential is engaged.

In some embodiments, the first motor and the second motor are configured to be independently controlled. In some embodiments, the center disconnecting differential includes a spider gearset coupled to a differential casing, a first side gear coupled to the first halfshaft and engaged with the spider gearset, and a second side gear coupled to the second halfshaft and engaged with the spider gearset. In some such embodiments, the center disconnecting differential includes a first thrust washer arranged between the first side gear and the first output gear, and a second thrust washer arranged between the second side gear and a stationary section of a housing.

According to another aspect of the invention, there is provided a method for managing drive modes of a drive axis. The method includes controlling a first clutch coupling a first output gear and a first halfshaft of the drive axis, controlling a second clutch coupling a second output gear and a second halfshaft of drive axis, controlling a differential configured to couple the first output gear to the first halfshaft and to the second halfshaft, and controlling at least one of a first motor coupled to the first output gear or a second motor coupled to the second output gear. The method includes determining to achieve a fully locked drive mode at the drive axis. The fully locked drive mode is achieved by causing to be engaged the first clutch, causing to be engaged the second clutch, and causing to be engaged the differential so that the first and second halfshafts are not free to rotate independently.

In some embodiments, the method includes determining to achieve a torque vectoring mode at the drive axis. The torque vectoring mode is achieved by causing to be engaged a first clutch coupling a first output gear and a first halfshaft of the drive axis, causing to be engaged a second clutch coupling a second output gear and a second halfshaft of drive axis, causing to be disengaged a differential configured for coupling and decoupling the first halfshaft and the second halfshaft, and independently controlling rotation of the first motor and rotation of the second motor.

In some embodiments, the method includes determining to achieve a single motor drive mode. The single motor drive mode is achieved by causing to be disengaged the first clutch, causing to be disengaged the second clutch, causing to be engaged the differential, and controlling rotation of the first motor. In some embodiments, in neutral mode, the method includes allowing the second motor to freewheel without electric power input.

In some embodiments, the method includes determining to achieve a neutral drive mode at the drive axis. The neutral drive mode is achieved by causing to be disengaged the first clutch, causing to be disengaged the second clutch, causing to be disengaged the differential, and allowing both the first motor and the second motor to freewheel without electric power input.

In some embodiments, the method includes determining a drive mode based on at least one of a signal from speed sensor, an energy consumption metric, an input to a user interface, a torque value of the first motor, or a torque value of the second motor.

The present invention, in accordance with one or more various embodiments, is described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or example embodiments. These drawings are provided to facilitate an understanding of the invention disclosed herein and shall not be considered limiting of the breadth, scope, or applicability of the invention, which is limited only by the scope of the appended claims. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.

The present invention is directed to motor drive unit architectures having a controllable differential. In some embodiments, the motor drive unit architecture aligns two or more motors on different axes. In some embodiments, the present invention is directed to drive units allowing a plurality of configurations to be realized. To illustrate, referencing a four-motor, torque vectoring capable, electric vehicle architecture (or a two-motor drive unit with torque vectoring to a pair of wheels at an axle), there may exist a large discrepancy between the amount of power and/or torque available from all four motors at any time and the amount of torque and/or power required to maintain a constant vehicle speed. Further, in situations where constant speed cruising is desired, it may be advantageous for efficiency, range, or both to use as few motors and drivetrains as possible. Electrical and/or mechanical means may be used to "turn off" or otherwise disengage as many of the other drivetrain systems, and reduce associated losses, as possible.

In some circumstances, dual drive units provide various advantages, including the ability to provide torque vectoring. The dual drive units of the present invention may provide one or more advantages. In some embodiments, the dual drive units of the present disclosure may be configured to fit into vehicles that are otherwise too small to fit the necessary hardware. This enables torque vectoring drive units to be appropriately packaged in smaller passenger vehicles. In some embodiments, the dual drive units of the present invention enable the use of relatively larger motors to fit in high performance applications that already employ torque vectoring drive units. This results in even more power in high output torque vectoring cars. In some embodiments, the dual drive units of the present invention enable the use of longer half shafts, which means more suspension travel is possible without compromising vehicle speed. Therefore, off-road applications or modes that require more suspension travel overall can be used at relatively higher speeds.

In some embodiments, the present invention is directed to a selectable differentiation gearbox which provides control over an operating range while providing torque vectoring, neutral differentiation, open-differentiation, single motor driving, and differential locking. In some embodiments, an electric drivetrain may include one or more electric motors configured to achieve torque vectoring (e.g., a two- or four-motor architecture). For example, a Front Drive Unit (FDU) and a Rear Drive Unit (RDU) may be included, and each may include two inverter cores, two motors, and two independent gearsets integrated into a single package.

<FIG> shows a top view of illustrative components of electric vehicle <NUM>, in accordance with some embodiments of the present invention. In some embodiments, a vehicle may include two or more electric motors, arranged in one or more drive units. For example, some of the motor assemblies may be identical, while some may have different handedness or shaft rotation direction relative to the motor. As illustrated, front drive unit <NUM> and rear drive unit <NUM> are oriented differently. The components and orientation of front drive unit <NUM> and rear drive unit <NUM> may be the same or different to accommodate suitable shaft rotations and fitment within the vehicle. Also illustrated in <FIG> is an exploded view of motor assembly <NUM>, motor assembly <NUM>, motor assembly <NUM>, and motor assembly <NUM>. Motor assemblies <NUM> and <NUM> are included in front drive unit <NUM> (e.g., along with other components such as a differential, intermediate housing, bearings, etc.). Motor assemblies <NUM> and <NUM> are included in rear drive unit <NUM> (e.g., along with other components such as a differential, intermediate housing, bearings, etc.). Front drive unit <NUM> and rear drive unit <NUM> may each include a differential, output shaft clutches, or both, to control the number of motors used, the number of output shafts driven, the independence of output shafts, or a combination thereof. For example, the differential and clutch assemblies of the present invention may be applied at the front wheels, rear wheels, or both. To illustrate, at each drive axis (e.g., front and rear), either zero, one, or two motors may be used to provide torque to wheels of the drive axis. For example, in some circumstances, only the front drive axis may be powered (e.g., one or both motors), and the rear drive axis may be neutralized (e.g., non-powered and allowed to freewheel). In a further example, in some circumstances, both the front drive axis and the rear drive axis may be powered (e.g., one or both motors at each axis). Table <NUM> provides illustrative examples of configurations that may be achieved by electric vehicle <NUM> wherein each of front drive unit <NUM> and rear drive unit <NUM> have differential assemblies included, in accordance with some embodiments of the present invention. In some embodiments, only one of front drive unit <NUM> and rear drive unit <NUM> include a differential, and only some of the configurations of Table <NUM> may be achievable or otherwise applicable.

<FIG> shows three illustrative drive unit configurations, in accordance with some embodiments of the present invention. Configuration <NUM> includes two separate motor drives <NUM> and <NUM>, each including a motor, gearbox (e.g., a housing), and output (e.g., an output spline or output half-shaft). Differential assembly <NUM> is installed and configured to couple or decouple the output of motor drives <NUM> and <NUM>. The housings of motor drives <NUM> and <NUM> interface to each other to form a stationary housing.

Configuration <NUM> includes motor drives <NUM> and <NUM>, illustrated in an exploded view (e.g., unassembled). Motor drives <NUM> and <NUM> are configured to be coupled together by intermediate housing <NUM>. In some embodiments, each of motor drives <NUM> and <NUM>, while including a motor (e.g., motors <NUM> and <NUM>), full gearset (e.g., gearsets <NUM> and <NUM>), and output (e.g., half-shafts <NUM> and <NUM>), need not be configured for stand-alone operation. As illustrated, motor drives <NUM> and <NUM> include, respectively, B-shields <NUM> and <NUM>, which may be configured to house a bearing, manage electrical terminations, provide cooling, provide mounting, any other suitable functions, or any suitable combination thereof. In some embodiments, motor drives <NUM> and <NUM> need not be sealing. For example, intermediate housing <NUM> (e.g., I-shield) may be configured to seal against both motor drive <NUM> and motor drive <NUM>. Intermediate housing <NUM> may be configured to seal lubricant (e.g., bearing oil), seal coolant (e.g., water, mixtures, oil), provide noise reduction (e.g., attenuate gear-induced audible noise and vibration), align motor drives <NUM> and <NUM> to each other, mount motor drives <NUM> and <NUM> to a frame or other structural element, house one or more shaft bearings (e.g., one or more bearings for a motor shaft, intermediate shaft, output shaft, or a combination thereof), any other suitable functionality, or any suitable combination thereof. Differential <NUM> is installed and configured to couple or decouple the output of motor drives <NUM> and <NUM>.

Configuration <NUM> includes motor drives <NUM> and <NUM> in an assembled state. For example, motor drives <NUM> and <NUM> may be affixed to intermediate housing <NUM> using fasteners (e.g., bolts, threaded studs and nuts), clamps, latches, mechanical interlocks, any other suitable affixments, or any combination thereof. In some embodiments, intermediate housing <NUM>, motor drive <NUM>, motor drive <NUM>, or a combination thereof may include alignment features that spatially align two or more components, constrain relative motion, or both. For example, intermediate housing <NUM> may allow each of motor drives <NUM> and <NUM> to be shorter (e.g., along the left-right axis, as illustrated in <FIG>). In a further example, configuration <NUM> may be shorter than configuration <NUM> along the left-right axis, as illustrated, because motor drives <NUM> and <NUM> need not require fully sealed gearsets <NUM> and <NUM>. Motor drives <NUM> and <NUM>, which are stand-alone, include housings that completely seal against lubrication, coolant, or both, and also house all bearings of the respective gearsets.

<FIG> shows an illustrative arrangement <NUM> of gears within gearboxes, in accordance with some embodiments of the present invention. Gearbox housings are not illustrated in <FIG> for clarity. Power train mechanisms, such as gearboxes, can assume various configurations and arrangements based on, for example, design constraints. For example, as illustrated in <FIG>, the motors and intermediate gears are offset from each other for purposes of illustration and clarity. Accordingly, in some embodiments, the motors and output shafts are aligned on respective axes (e.g., as illustrated in <FIG>). The motors, output gears, or both, may be aligned on respective axes, in accordance with the present invention (e.g., first gears <NUM> and <NUM> may be centered about the same axis). To illustrate, the offset arrangement of <FIG> allows each power transfer mechanism to be illustrated (e.g., illustrated as a "V", however the minor angle of the "V" may be zero degrees to form a motor-aligned arrangement).

As illustrated in <FIG>, each gearset (e.g., gears <NUM>, <NUM>, <NUM>, and <NUM> are one gearset, and gears <NUM>, <NUM>, <NUM>, and <NUM> are another gearset) includes a double reduction gear. Each motor (e.g., motor <NUM> and motor <NUM>), includes a motor shaft having a first gear. For example, first gear <NUM> is affixed to the shaft of motor <NUM>, and first gear <NUM> is affixed to the shaft of motor <NUM>. Each first gear pairs with a larger of two intermediate gears that rotate about an intermediate axis. For example, first gear <NUM> engages with intermediate gear <NUM> affixed to an intermediate shaft. Intermediate gear <NUM>, coupled to the same intermediate shaft as intermediate gear <NUM> engages with respective output gear <NUM> (e.g., coupled to a respective output shaft <NUM>). Further, first gear <NUM> engages with intermediate gear <NUM> affixed to an intermediate shaft. Intermediate gear <NUM>, coupled to the same intermediate shaft as intermediate gear <NUM> engages with respective output gear <NUM> (e.g., coupled to a respective output shaft <NUM>, aligned with output shaft <NUM>). It will be understood that, as illustrated in <FIG>, output gears <NUM> and <NUM> are aligned, with output gear <NUM> being positioned behind output gear <NUM>, and only output shaft <NUM> visible. As described herein, the intermediate shafts may be offset (e.g., not aligned along a line) from the respective motor shaft and drive shaft. It will be understood that any suitable number of gears may be used with any suitable amount of reduction between a motor and corresponding output shaft. In some embodiments, the gearbox may include two or more gears in a gear train. The gear train may include an ordinary gear train or a compound ordinary gear train. For example, a compound gear train may include two gears configured to rotate about a single axis. Gears may include any suitable gear types such as, for example, spur gears, parallel helical gears, any other suitable gear type, or any suitable combination thereof. It will be understood that while the illustrative drive units of the present invention are illustrated as including gearboxes and gears, any suitable power transfer mechanisms may be used to transfer power from a motor to an output, in accordance with the present invention. For example, chain drives, belt drives may be used. In a further example, a belt tensioner, cog, sprocket, any other suitable hardware, or combination thereof, may be included to transfer power, maintain engagement, or both. In a further example, any suitable number of reductions may be included in a power transfer mechanism. As illustrated, two reduction stages are included using three total gears, however a gear set may include two gears, three gears, or more than three gears, for example. In some embodiments, a power transfer mechanism (e.g., either gearset of <FIG>) is configured to reduce a rotation rate of an output shaft (e.g., an output shaft) relative to a rotation rate of a motor shaft. As used herein, a power transfer mechanism may refer to one or more components for transmitting shaft work among shafts. For example, a power transfer mechanism may include a gearset (e.g., a plurality of gears, each engaged with at least one other gear), a single gear (e.g., engaged with other gears such as an input gear and an output gear), bearings, any other suitable components, or any combination thereof. For example, the set of a motor gear, an intermediate gear, and an output gear may be referred to as a power transfer mechanism, or the intermediate gear alone may be referred to as a power transfer mechanism.

<FIG> shows a cross-sectional view of illustrative arrangement <NUM> for nested drive gears, clutch assemblies, and a differential assembly, in accordance with some embodiments of the present invention. To illustrate, arrangement <NUM> may be, but need not be, similar to arrangement <NUM> of <FIG> with addition of clutch assemblies and a differential assembly. Arrangement <NUM>, as illustrated, represents a portion of a drivetrain and includes drive gear <NUM>, drive gear <NUM>, bearings <NUM>-<NUM>, clutch assemblies <NUM> and <NUM>, output elements <NUM> and <NUM>, and differential elements <NUM>-<NUM> with actuator <NUM> (e.g., to lock and unlock drive gear <NUM> from differential elements <NUM>). Drive gear <NUM> is driven by a first motor (e.g., in a similar arrangement as illustrated in <FIG>) and drive gear <NUM> is driven by a second motor (e.g., in a similar arrangement as illustrated in <FIG>). Bearings <NUM>-<NUM> maintain alignment of drive gears <NUM> and <NUM> along axis <NUM> during rotation and loading (e.g., axial loading, radial loading, and azimuthal loading). As illustrated, drive gear <NUM> nests radially within drive gear <NUM> along a section, with bearing <NUM> arranged radially in between. As illustrated, bearings <NUM>-<NUM> are arranged between rotating components and stationary elements of the gearbox housing (not shown in <FIG>). Clutch assembly <NUM> is configured to engage and disengage drive gear <NUM> from output element <NUM>. Similarly, clutch assembly <NUM> is configured to engage and disengage drive gear <NUM> from output element <NUM>. Each of clutch assemblies <NUM> and <NUM> may include an actuator that is mounted to the stationary elements of the housing (not shown in <FIG>). Actuator <NUM> is configured to engage and disengage drive gear <NUM> from differential elements <NUM>-<NUM>. In some embodiments, differential element <NUM> includes a differential casing that can be engaged with (e.g., rotate with) drive gear <NUM> or disengaged from (e.g., rotate differently from) drive gear <NUM>.

Bearings <NUM>-<NUM> may include, for example, roller bearings, needle bearings, ball bearings, taper bearings, thrust bearings, any other suitable type of bearing, or any combination thereof. In some embodiments, bearings <NUM> and <NUM> are configured to react against a stationary component (e.g., a housing or other component) to maintain alignment of drive gears <NUM> and <NUM> relative to the stationary component. In some embodiments, bearing <NUM> is configured to react against a stationary component (e.g., a housing or other component) to maintain alignment of drive gear <NUM> relative to the stationary component. Because of the axial overlap of drive gears <NUM> and <NUM>, bearing <NUM> may be configured to transmit forces in the radial direction, axial direction, or both, between drive gears <NUM> and <NUM>.

Drive gears <NUM> and <NUM> (also referred to as "output gears") are configured to engage with respective bearings <NUM> and <NUM>, which engage with a stationary component (e.g., a housing) to maintain alignment of drive gears <NUM> and <NUM>. As illustrated, drive gear <NUM> and output element <NUM> may be referred to as "left (L)" for "<NUM>" while drive gear <NUM> and output element <NUM> may be referred to as "right (R)" or "<NUM>" herein. In some embodiments, output elements <NUM> and <NUM> each include a side gear (e.g., engaged with differential elements <NUM> and <NUM>), a half shaft and a clutch element that is configured to be engaged and disengaged from respective drive gears <NUM> and <NUM> by respective clutch assemblies <NUM> and <NUM>. In some embodiments, output elements <NUM> and <NUM> are each configured to be outputs, and may include output interfaces. For example, output elements <NUM> and <NUM> each may include a recess configured to accommodate a half shaft. In a further example, output elements <NUM> and <NUM> each may include any suitable output interface such as, for example, a splined interface, a keyed interface, a flanged interface (e.g., with fasteners), a universal joint, a clutched interface, any other suitable interface, or any combination thereof. In an illustrative example, the differential assembly may be referred to as a center disconnecting differential that is coupled to output elements <NUM> and <NUM>, and is configured to connect and disconnect (e.g., via actuator <NUM>) drive gear <NUM> from differential element <NUM> (e.g., which includes a differential casing).

Clutch assemblies <NUM> and <NUM> of bearing arrangement <NUM> is configured to mechanically couple drive gears <NUM> and <NUM> with respective output elements <NUM> and <NUM>. Clutch assemblies <NUM> and <NUM> may include, for example, friction plates, pressure plates, actuators (e.g., hydraulic, electromechanical, mechanical), centrifugal elements, conical elements, a torque limiter, dampers, springs (e.g., to reduce chatter, to release engagement), dog clutch elements (e.g., for non-slip engagement), any other suitable elements, or any combination thereof. Clutch assemblies <NUM> and <NUM> may partially interface to a stationary component (e.g., a housing or extension thereof), which provides a structure to transmit force. For example, a linear actuator may be used to engage the clutch assembly, and a stator of the linear actuator may be affixed to the stationary component. In a further example, an engagement mechanism of the clutch assembly may be affixed to the stationary component to provide a structure against which the engagement mechanism reacts a force.

In an illustrative example, in torque vectoring mode, drive gears <NUM> and <NUM> may rotate about axis <NUM> as substantially the same speed when the vehicle is traveling straight on relatively consistent ground. During turning or under condition where one side may experience more traction or more slip, drive gears <NUM> and <NUM> may rotate at different speeds about axis <NUM> (e.g., drive gears <NUM> and <NUM> rotate relative to each other about axis <NUM>). In some such circumstances, for example, wherein one wheel experiences slip, the differential assembly may be engaged to transmit more power to the wheel with more traction.

<FIG> show cross-sectional views of illustrative arrangement <NUM> of <FIG> in different driving modes, in accordance with some embodiments of the present invention. <FIG> illustrates a torque vectoring mode, <FIG> illustrates a fully locked mode, and <FIG> illustrates a single motor mode. Additionally, a neutral mode may be achieved, wherein the differential assembly and clutch assemblies are disengaged, and thus the drive axis is not driven by either motor (e.g., rotates passively when the other drive axis is driven). Axis <NUM> of <FIG> is included in each of <FIG> for reference.

Referencing <FIG>, illustrating a torque vectoring mode, output <NUM> is driven by the first motor and output <NUM> is driven by the second motor. The differential assembly is unlocked (e.g., shown as dotted in <FIG>, with actuator <NUM> disengaged), while both clutch assemblies <NUM> and <NUM> are locked. For example, in torque vectoring mode, each motor drives the respective output (e.g., output elements <NUM> and <NUM>) independent from each other. In a further example, the first motor only drives output <NUM> and the second motor only drives output <NUM>, and each of outputs <NUM> and <NUM> may rotate at different speeds and exhibit a different amount of torque (e.g., outputs <NUM> and <NUM> are hashed differently in <FIG>).

Referencing <FIG>, illustrating a fully locked mode, the differential assembly is disengaged (e.g., via actuator <NUM>) and both clutch assemblies <NUM> and <NUM> are engaged such that output <NUM> (e.g., including both output shafts to both wheels) is driven by the first motor, the second motor, or both. Unlike the torque vectoring mode of <FIG>, the output shafts are not free to rotate independently (e.g., wheels of the drive axis rotate at the same speed), and either or both motors may be used to drive output <NUM>. To illustrate, if one wheel were to slip in fully locked mode, the torque provided by both the first motor and the second motor could be utilized by the non-slipping wheel in fully locked mode.

Referencing <FIG>, illustrating a single motor mode, both clutch assemblies <NUM> and <NUM> are disengaged and the differential assembly is engaged (e.g., via actuator <NUM>). As illustrated, only the first motor drives output <NUM>. The second motor may freewheel but is otherwise not engaged with output <NUM> and does not provide torque to output <NUM> (e.g., except perhaps negligible friction from relative moving surfaces and viscous drag). In single motor mode, for example, a single motor is used to drive the wheels on the drive axis, thus reducing the electrical power requirements for that drive axis.

<FIG> shows a cross-sectional view of drive system <NUM> having a differential, in accordance with some embodiments of the present invention. As illustrated, drive system <NUM> includes: housing <NUM> including housing elements <NUM> and <NUM>, and stationary elements <NUM>; output gears <NUM> and <NUM>; spider gears <NUM> and <NUM>; shaft <NUM> and frame <NUM>; side gears <NUM> and <NUM>; differential actuator <NUM>; halfshafts <NUM> and <NUM>, possibly also referred to as output shafts <NUM> and <NUM> and/or halfshafts to constant velocity joints <NUM> and <NUM>; clutch elements <NUM>, <NUM>, <NUM>, and <NUM>; clutch actuators <NUM> and <NUM>; bearings <NUM>, <NUM>, <NUM>, and <NUM>; and seals <NUM> and <NUM>.

Housing <NUM> is configured to be stationary relative to output gears <NUM> and <NUM>, and may be mounted to a frame of an electric vehicle, for example. Output gears <NUM> and <NUM> are engaged with respective gears (not shown) that may be either motor gears or intermediate gears engaged with motor gears. Further, although not illustrated in <FIG>, two electric motors are included and coupled to housing <NUM>, with respective motor shafts engaged via respective motor gears to drive gears <NUM> and <NUM>, either directly or via one or more respective intermediate gears. Output shafts <NUM> and <NUM> (e.g., referred to as "halfshafts" herein) may be coupled to respective wheels of the drive axis by a universal joint, half shaft, spindle, any other suitable linkage, or any combination thereof. Seals <NUM> and <NUM> are configured to seal output shafts <NUM> and <NUM> to housing <NUM> to allow azimuthal displacement (e.g., rotation about axis <NUM>) while preventing or limiting leakage of lubricant from the inner volume of housing <NUM>. To illustrate, drive system <NUM> may include an oil lubricating system wherein oil is pumped and/or splashed on components arranged within housing <NUM>, and seals <NUM> and <NUM> help contain the lubricant in the inner volume of housing <NUM>.

Output gear <NUM> interfaces to bearings <NUM> and <NUM> to constrain displacement off of axis <NUM> (e.g., output fear <NUM> is constrained to a single degree of freedom to rotate about axis <NUM>). To illustrate, output gear <NUM> may be a single piece or a rigid assembly of more than one piece. For example, as illustrated, output gear <NUM> includes a first piece that is driven and interfaces to clutch element <NUM> and a second piece that interfaces to bearing <NUM>. Output gear <NUM> interfaces to bearings <NUM>, <NUM>, and <NUM> to constrain displacement off of axis <NUM> (e.g., output gear <NUM> is constrained to a single degree of freedom to rotate about axis <NUM>). Output gears <NUM> and <NUM> may rotate about axis <NUM> relative to each other in some drive modes (e.g., torque vectoring mode, single motor mode, neutral mode), and may be constrained to rotate together (e.g., at the same speed) in some drive modes (fully locked mode).

Clutch element <NUM> (e.g., a clutch disk) is affixed to output shaft <NUM> (e.g., by splines, keys, or any other suitable affixment constraining relative azimuthal rotation). Clutch element <NUM> (e.g., a clutch disk) is affixed to drive gear <NUM> (e.g., by splines, keys, or any other suitable affixment constraining relative azimuthal rotation). Clutch actuator <NUM> is configured to engage and disengage clutch elements <NUM> and <NUM> from each other, thus engaging or disengaging output gear <NUM> and output shaft <NUM> from each other. To illustrate, when clutch actuator <NUM> causes clutch elements <NUM> and <NUM> to be engaged, output gear <NUM> and output shaft <NUM> rotate at the same angular rate and torque is transferred between output gear <NUM> and output shaft <NUM>. In some embodiments, some slip may occur between clutch elements <NUM> and <NUM> when engaged, although slip need not be exhibited in other embodiments.

Drive system <NUM> includes a differential assembly (e.g., a center disconnecting differential) that includes spider gears <NUM> and <NUM>, shaft <NUM>, frame <NUM>, side gears <NUM> and <NUM>, and differential actuator <NUM>. Frame <NUM> and shaft <NUM> may also be referred to as a differential casing, which may be engaged to rotate with output gear <NUM> or rotate different from output gear <NUM>. Side gear <NUM> is affixed to output shaft <NUM> (e.g., splined, keyed or bolted together) and is configured to rotate with output shaft <NUM>. Side gear <NUM> is affixed to output shaft <NUM> (e.g., splined, keyed or bolted together) and is configured to rotate with output shaft <NUM>. Spider gears <NUM> and <NUM> are configured to rotate about shaft <NUM>. In some embodiments, frame <NUM> is affixed to shaft <NUM>, while in other embodiments, frame <NUM> and shaft <NUM> may include a single component. Differential actuator <NUM> is configured to engage and disengage output gear <NUM> and frame <NUM>. As illustrated, differential actuator <NUM> is engaged, and thus frame <NUM>, shaft <NUM>, and spider gears <NUM> and <NUM> rotate with output gear <NUM> about axis <NUM>. Further as illustrated, output gear <NUM> includes splines <NUM>, which are configured to engage with differential actuator <NUM>. Although not visible in <FIG>, frame <NUM> includes corresponding splines such that, in the configuration illustrated in <FIG>, differential actuator <NUM> also engages splines of frame <NUM> such that frame <NUM> and output gear <NUM> rotate together. The assembly including spider gears <NUM> and <NUM>, shaft <NUM>, and frame <NUM> is referred to herein as a spider gearset, which may rotate about axis <NUM>. In an illustrative example, the differential assembly couples output shafts <NUM> and <NUM> together (e.g., and is configured to differentiate torque to output shafts <NUM> and <NUM>), and differential actuator <NUM> is configured to connect and disconnect output gear <NUM> from frame <NUM> (e.g., a differential casing).

Bearings <NUM> and <NUM>, as illustrated, are arranged between housing <NUM> (e.g., housing elements <NUM> and <NUM>, respectively) and respective output gears <NUM> and <NUM> (e.g., extensions thereof such as surfaces machined to accommodate bearing journals). Bearings <NUM> and <NUM> constrain radial and axial displacement relative to axis <NUM>, while allowing azimuthal displacement (i.e., rotation about axis <NUM>). Bearing <NUM> is arranged between output gear <NUM> and output gear <NUM>, thus constraining relative radial displacement, while allowing relative azimuthal displacement (e.g., relative rotation). Bearing <NUM> is arranged between output gear <NUM> and stationary component <NUM> of housing <NUM>, thus constraining radial displacement, at least, of output gear <NUM> while allowing azimuthal displacement (e.g., rotation about axis <NUM>).

<FIG> show cross-sectional views of illustrative drive system <NUM> of <FIG> in different driving modes, in accordance with some embodiments of the present invention. Not all of the labels of <FIG> are not included in <FIG> for purposes of clarity, and bearings, housings, clutch actuators, seals, and other features are omitted for purposes of clarity. Hatching is used in <FIG> to illustrate components constrained to rotate as rigid bodies, and components exhibiting potential relative rotation. In an illustrative example, the drive modes illustrated in <FIG> correspond to the drive modes of <FIG>, respectively.

Referencing <FIG>, illustrating a torque vectoring mode, output gear <NUM> is driven by the first motor and output gear <NUM> is driven by the second motor. The differential assembly is unlocked (e.g., frame <NUM> is disengaged from output gear <NUM>), while both clutch assemblies are locked at least some of the time (clutch elements <NUM> and <NUM> are engaged with each other, and clutch elements <NUM> and <NUM> are engaged with each other). Output <NUM> is driven by output gear <NUM>, when clutch elements <NUM> and <NUM> are engaged, while output <NUM> is driven by output gear <NUM>, when clutch elements <NUM> and <NUM> are engaged. For example, in torque vectoring mode, each motor (e.g., a first and second motor) drives the respective output (e.g., outputs <NUM> and <NUM>) independent from each other. To illustrate, the first motor only drives output gear <NUM> and the second motor only drives output gear <NUM>, and each of output gears <NUM> and <NUM> may rotate at different speeds and exhibit a different amount of torque. Frame <NUM>, shaft <NUM>, and spider gears <NUM> and <NUM> may rotate about axis <NUM> relative to both locked components <NUM> and <NUM> (e.g., the differential is disengaged). Accordingly, spider gears <NUM> and <NUM> rotate about the axis of shaft <NUM> if outputs <NUM> and <NUM> rotate at different angular rates.

Referencing <FIG>, illustrating a fully locked mode, the differential assembly and both clutch assemblies are engaged such that both output shafts <NUM> and <NUM> are driven as a rigid body by the first motor, the second motor, or both. Unlike the torque vectoring mode of <FIG>, output shafts <NUM> and <NUM> are not free to rotate independently (e.g., wheels of the drive axis rotate at the same speed), and either or both motors may be used to drive the wheels. To illustrate, if one wheel were to slip in fully locked mode, the torque provided by both the first motor and the second motor could be utilized by the non-slipping wheel in fully locked mode. To illustrate further, spider gears <NUM> and <NUM> do rotate about the axis of shaft <NUM> because both side gears <NUM> and <NUM> are constrained to rotate together (e.g., as part of the rigid body).

Referencing <FIG>, illustrating a single motor mode, both clutch assemblies are disengaged and the differential assembly is engaged. The single motor mode (also referred to as hyper-mile mode or eco mode) allows the front drive unit to be reduced from two motors and gearsets being active, to a single motor and gearset being used for powering a drive axis (e.g., both front wheels or both rear wheels). Only the first motor, which drives output gear <NUM>, drives output shafts <NUM> and <NUM> in single motor mode. The second motor, which drives output gear <NUM> in some other drive modes, may freewheel but is otherwise not engaged with, and does not provide torque to, output shafts <NUM> or <NUM>. In single motor mode, for example, a single motor is used to drive the wheels on the drive axis (e.g., along axis <NUM>), thus reducing the electrical power requirements for that drive axis (e.g., incurring less motor, power electronics, and/or power transmission loss). Differential actuator <NUM> is engaged, and thus frame <NUM> and shaft <NUM> rotate about axis <NUM> with output gear <NUM>. However clutch actuators <NUM> and <NUM> are not engaged (i.e., are disengaged) and thus side gears <NUM> and <NUM> are driven by spider gears <NUM> and <NUM>. Accordingly, output shafts <NUM> and <NUM> may, but need not, rotate at the same angular rate. For example, during driving along a straight path, output shafts <NUM> and <NUM> rotate at the same speed, and spider gears <NUM> and <NUM> do not rotate relative to the axis of shaft <NUM>. In a further example, during driving along a turn or surface with mismatched friction/grip, output shafts <NUM> and <NUM> may rotate at different speeds, in which case spider gears <NUM> and <NUM> rotate relative to the axis of shaft <NUM>. Output gear <NUM> is not engaged with output shaft <NUM> (or output shaft <NUM>), and may freewheel, for example (e.g., or may incidentally rotate from viscous drag as output shaft <NUM> rotates).

<FIG> shows a perspective partial cross-sectional view of illustrative drive system <NUM>, in accordance with some embodiments of the present invention. <FIG> illustrates the external surface of housing <NUM>, having housing elements <NUM> and <NUM> joined together. Further, <FIG> illustrates a cut-away view, wherein some of housing <NUM> is cut-away to expose output gears <NUM> and <NUM>. As illustrated, drive system <NUM> includes housing <NUM>, output gears <NUM> and <NUM> (e.g., driven by respective motors), differential actuator <NUM>, clutch actuators <NUM> and <NUM>, and output shafts <NUM> and <NUM>. In an illustrative example, drive system <NUM> may be the same as drive system <NUM> of <FIG>.

<FIG> shows a cross-sectional view of a portion of illustrative drive system <NUM> having an integrated differential, in accordance with some embodiments of the present invention. As illustrated, output gear <NUM> includes extensions <NUM> and <NUM>, although it will be understood that an output gear may be a single piece, or an assembly of pieces configured to rotate about axis <NUM> as a rigid body. For example, extensions <NUM> and <NUM> rotate as a rigid body with the rest of output gear <NUM>. As illustrated, drive system <NUM> includes a differential assembly that includes spider gears <NUM> and <NUM>, shaft <NUM>, frame <NUM>, side gears <NUM> and <NUM>, and differential actuator <NUM>. Side gear <NUM> is configured to be affixed to an output shaft (not shown) engaged with interface <NUM> (e.g., splined, keyed or bolted together) and is configured to rotate with the output shaft. Side gear <NUM> is configured to be affixed to an output shaft (not shown) engaged with interface <NUM> (e.g., splined, keyed or bolted together) and is configured to rotate with the output shaft. To illustrate, side gear <NUM> can rotate relative to output gear <NUM> (e.g., extension <NUM> thereof) driven by a first motor (not shown), and side gear <NUM> can rotate relative to output gear <NUM> (e.g., extension <NUM> thereof). Thrust washers <NUM> and <NUM> are arranged axially between extensions <NUM> and <NUM>, respectively. Thrust washers <NUM> and <NUM> allow relative azimuthal displacement (e.g., relative rotation) between side gears <NUM> and <NUM> and respective extensions <NUM> and <NUM>. Spider gears <NUM> and <NUM> are configured to rotate about the axis of shaft <NUM> (e.g., a vertical axis parallel to axis <NUM>, as illustrated). In some embodiments, frame <NUM> is affixed to shaft <NUM>, while in other embodiments, frame <NUM> and shaft <NUM> may include a single component.

Differential actuator <NUM> is configured to engage and disengage output gear <NUM> and frame <NUM>. As illustrated, differential actuator <NUM> is engaged, and thus frame <NUM>, shaft <NUM>, and spider gears <NUM> and <NUM> rotate with output gear <NUM> about axis <NUM>. Further as illustrated, output gear <NUM> includes splines (not visible in <FIG>) configured to engage with plunger <NUM> of differential actuator <NUM>. Although not visible in <FIG>, frame <NUM> includes corresponding splines such that, in the configuration illustrated in <FIG>, plunger <NUM> of differential actuator <NUM> also engages splines of frame <NUM> such that frame <NUM> and output gear <NUM> rotate together. Plunger <NUM> is configured to translate parallel to axis <NUM> ("axially"), to engage and disengage output gear <NUM> from the differential assembly (e.g., frame <NUM> thereof).

<FIG> shows a cross-sectional view of a portion of illustrative drive system <NUM> having a coupling, in accordance with some embodiments of the present invention. Drive system <NUM> includes output gears <NUM> and <NUM> (e.g., driven by respective motors, which are not shown in <FIG>), coupling <NUM>, and disconnects <NUM> and <NUM>. Output gears <NUM> and <NUM> are configured to be driven independently by respective electric motors. Disconnects <NUM> and <NUM>, which may include respective clutch assemblies, are configured to couple and decouple output gears <NUM> and <NUM> from respective wheels. Coupling <NUM>, which may include a differential assembly or a clutch assembly, is configured to couple and decouple output gears <NUM> and <NUM>. For example, when engaged, coupling <NUM> may allow a fully locked mode and/or single motor mode to be achieved (e.g., driven by either or more both motors). In a further example, when disengaged, coupling <NUM> may allow a torque vectoring mode to be achieved. In some embodiments, each of coupling <NUM> and disconnects <NUM> and <NUM> may include one or more actuators controlled by a control system to achieve one or more drive modes. In some embodiments, coupling <NUM> includes a differential assembly, with a spider gearset coupled to one of output gears <NUM> and <NUM>, with output shafts coupled to respective side gears engaged with the spider gearset.

<FIG> shows a cross-sectional view of a portion of drive system <NUM> having an intermediate differential assembly <NUM>, in accordance with some embodiments of the present invention. As illustrated, differential assembly <NUM> includes housing <NUM>, rather than being integrated within a drive system housing (e.g., as illustrated in <FIG>). Drive system <NUM> includes output gears <NUM> and <NUM>, bearings <NUM>-<NUM>, and differential assembly <NUM>. Differential assembly <NUM> may be bolted on or otherwise mounted to housings enclosing output gears <NUM> and <NUM>. To illustrate, in some embodiments, differential assembly <NUM> may be installed intermediate to existing housings corresponding to each of output gears <NUM> and <NUM>, as an add-on component rather than an integrated component.

Bearings <NUM> and <NUM> are configured to constrain radial and axial displacement of output gear <NUM> relative to axis <NUM>, while allowing azimuthal displacement (e.g., rotation) of output gear <NUM> about axis <NUM>. Bearings <NUM> and <NUM> are configured to constrain radial and axial displacement of output gear <NUM> relative to axis <NUM>, while allowing azimuthal displacement (e.g., rotation) of output gear <NUM> about axis <NUM>. Differential assembly <NUM> includes housing <NUM>, which is configured to be stationary, and side gears <NUM> and <NUM>, which are configured to engage a spider gearset (not shown in <FIG>). Each of side gears <NUM> and <NUM>, as illustrated, include splines for coupling to respective output shafts (similar to drive system <NUM> of <FIG>). Differential assembly <NUM> may also include an actuator for locking and unlocking the differential. For example, when locked, the drive axis is fully locked (e.g., output gears <NUM> and <NUM> rotate at the same rate) and, when unlocked, the drive axis may achieve a neutral or torque vectoring mode.

<FIG> shows a cross-sectional view of a portion of illustrative drive system <NUM> having an intermediate differential and intermediate clutches, in accordance with some embodiments of the present invention. As illustrated, drive system <NUM> includes output gears <NUM> and <NUM>, planetary differential <NUM>, output shafts <NUM> and <NUM>, and bearings <NUM>-<NUM>. Although not illustrated in <FIG>, drive system <NUM> also includes a housing having stationary components. Differential assembly <NUM> may be bolted on or otherwise mounted to housings enclosing output gears <NUM> and <NUM>. To illustrate, in some embodiments, differential assembly <NUM> may be installed intermediate to existing housings corresponding to each of output gears <NUM> and <NUM>, as an add-on component rather than an integrated component. Output gear <NUM> drives output shaft <NUM>, which rotates with gear <NUM>, all of which rotate with housing <NUM>. Output gear <NUM> drives output shaft <NUM>, which rotate with gear <NUM>.

Bearings <NUM> and <NUM> are configured to constrain radial and axial displacement of output gear <NUM> relative to axis <NUM>, while allowing azimuthal displacement (e.g., rotation) of output gear <NUM> about axis <NUM>. Bearings <NUM> and <NUM> are configured to constrain radial and axial displacement of output gear <NUM> relative to axis <NUM>, while allowing azimuthal displacement (e.g., rotation) of output gear <NUM> about axis <NUM>. Differential assembly <NUM> includes housing <NUM>, which is capable of rotation, planetary gears <NUM>, and gears <NUM> and <NUM>, which are configured to engage planetary gear <NUM>. Each of gears <NUM> and <NUM> may include splines or keys for coupling to respective output shafts <NUM> and <NUM>. Differential assembly <NUM> may also include an actuator for locking and unlocking the differential. For example, when locked, the drive axis is fully locked (e.g., output gears <NUM> and <NUM> rotate at the same rate) and, when unlocked, the drive axis may achieve a neutral or torque vectoring mode. To illustrate, when unlocked, planetary gear <NUM> may rotate about axis <NUM>, and gears <NUM> and <NUM> may rotate about axis <NUM> at different rates.

<FIG> shows a cross-sectional view of illustrative drive system <NUM>, in accordance with some embodiments of the present invention. As illustrated, drive system <NUM> includes housing <NUM>, motors <NUM> and <NUM>, intermediate gearsets <NUM> and <NUM>, output gears <NUM> and <NUM>, outputs <NUM> and <NUM>, mounts <NUM> and <NUM>. As illustrated, drive system <NUM> does not include a differential assembly, although a suitable differential assembly may be integrated or output gears <NUM> and <NUM> and outputs <NUM> and <NUM> may be replaced with output gears having an integrated differential assembly. Motors <NUM> and <NUM> include respective motor gears, which engage with respective intermediate gearsets <NUM> and <NUM>, which in turn engage with respective output gears <NUM> and <NUM>. Outputs <NUM> and <NUM> include disconnects, and are splined to interface to respective drive shafts. Mounts <NUM> and <NUM> affix housing <NUM> to the electric vehicle, and may include fasteners, bushings, any other suitable components, or any combination thereof. Clutch assemblies <NUM> and <NUM> allow coupling of output gear <NUM> and output <NUM>, and output gear <NUM> and output <NUM>, respectively. In an illustrative example, any of the illustrative arrangements and drive systems of <FIG> may retrofitted into, or combined with drive system <NUM> to provide differential functionality. To illustrate, output gears <NUM> and <NUM>, and any other suitable components, may be redesigned, replaced, or otherwise modified to accommodate a differential assembly.

<FIG> shows a block diagram of illustrative electric vehicle <NUM> having a control system for controlling one or more drive units, in accordance with some embodiments of the present invention. Electric vehicle <NUM> includes battery pack <NUM>, electric vehicle subsystems <NUM>, suspension, and wheels. Electrical vehicle subsystems <NUM> includes, for example, rear drive unit <NUM>, front drive unit <NUM>, control circuitry <NUM>, auxiliary systems <NUM>, input interface <NUM>, and any other suitable corresponding equipment. Electric vehicle <NUM> includes power transfer mechanism <NUM> (e.g., a gearbox, pulley system, or other mechanism for transferring shaft work) corresponding to one drive axis (e.g., rear drive axis) and power transfer mechanism <NUM> corresponding to another drive axis (e.g., front drive axis). Electric vehicle <NUM> may be the same as electric vehicle <NUM> of <FIG>, for example, wherein front drive unit <NUM> and rear drive unit <NUM> correspond to power transfer mechanisms <NUM> and <NUM>, respectively. In a further example, vehicle <NUM> may include any of the illustrative arrangements and drive systems of <FIG> as part of either or both of power transfer mechanisms <NUM> and <NUM>. Vehicle subsystems <NUM> may be used to, for example, monitor operation (e.g., sensor signals) of any of the illustrative arrangements and drive systems of <FIG>, control actuators (e.g., clutch actuators and/or differential actuators) of any of the illustrative arrangements and drive systems of <FIG>, or otherwise manage operation of any of the illustrative arrangements and drive systems of <FIG>. To illustrate, each of power transfer mechanisms <NUM> and <NUM> may include a left side gear train corresponding to a left halfshaft and a right side gear train corresponding to a right halfshaft.

In some embodiments, control circuitry <NUM> may include processing equipment, memory, power management components, any other suitable components for controlling one or more drive unit (e.g., front drive unit <NUM> and rear drive unit <NUM>), or any combination thereof. For example, control circuitry <NUM> may control current flow (e.g., amount of current and current direction) to phases of an electric motor of one or more drive units (e.g., using electric power as stored in battery pack <NUM>). In a further example, control circuitry <NUM> may control clutch operation (e.g., using an electromagnetically-actuated clutch) for one or more clutch assemblies. In a further example, control circuitry <NUM> may control differential operation (e.g., using an electromagnetically-actuated differential) in a dual drive unit. In some embodiments, control circuitry <NUM> is configured to actuate and de-actuate one or more clutch actuators (e.g., a first and second clutch actuator), a differential actuator, or a combination thereof. For example, control circuitry may provide control signals (e.g., communications, electric power, or both) to (i) one or more clutch actuators of power transfer mechanism <NUM>, <NUM>, or both, (ii) one or more differential actuators of power transfer mechanism <NUM>, <NUM>, or both, or (iii) a combination thereof. In a further example, the control signals may be binary (e.g., on/off application of a DC voltage), analog (e.g., the control signal may be proportional based on a voltage range, pulse-width modulation, or pulse-density modulation), oscillatory (e.g., and AC signal or other oscillating signal), any other suitable waveform or shape (e.g., square wave, sawtooth wave, triangular wave, rectified sinusoidal wave), or any combination thereof. In some embodiments, actuators are spring-loaded or otherwise biased in an engaged or disengaged state, and application of electrical power, hydraulic power, or pneumatic power from vehicle subsystem <NUM> causes a change in state (e.g., engaged to disengaged, or disengaged to engaged).

In some embodiments, control circuitry <NUM> may include one or more sensors, one or more sensor interfaces (e.g., for sensors that are included as part of a drive unit), corresponding wiring, corresponding signal conditioning components, any other suitable components for sensing a state of a drive unit, or any combination thereof. For example, control circuitry <NUM> may include a speed sensor (e.g., a rotary encoder), a current sensor, a voltage sensor, a temperature sensor, any other suitable sensor, or any combination thereof. In some embodiments, control circuitry <NUM> may be implemented by a central controller, a plurality of distributed control systems, an embedded system, or any combination thereof. For example, control circuitry <NUM> may be at least partially implemented by an electronic control unit (ECU). In a further example, the electric vehicle may include a power electronics system that is controlled by the ECU and is configured to manage current to one or more electric motors of one or more drive units. Rear drive unit <NUM> may be coupled to wheels of the electric vehicle by a half shaft, a constant-velocity joint, one or more suspension/steering components, any other suitable coupling, or any suitable combination thereof. Front drive unit <NUM> may be coupled to wheels of the electric vehicle by a half shaft, a constant-velocity joint, one or more suspension/steering components, any other suitable coupling, or any suitable combination thereof. For example, a wheel may be mounted to a hub that is includes a bearing for a half-shaft, wherein the hub is coupled to suspension/steering components that are mounted to the vehicle frame (e.g., wherein the drive units are also mounted to the vehicle frame).

In some embodiments, a drive system may include a first drive unit and optionally a second drive unit, each including one or more clutch assemblies, and a differential assembly. In some embodiments, a system, in addition to including a drive unit (e.g., single or dual), may include processing equipment configured to activate and deactivate the clutch assembly to transfer torque, manage motor operation, manage regeneration (e.g., using the motor as a generator), perform any other control function, or any combination thereof. Activating and deactivating a clutch assembly may refer to completely, or partially, increasing or decreasing the engagement of elements of the clutch assembly (e.g., using control circuitry). For example, activating a clutch assembly may include completely locking the clutch, allowing some slip of the clutch, or otherwise transferring an amount of torque between the output shafts. In some embodiments, the drive unit may include at least one sensor (e.g., coupled to a sensor interface of control circuitry) configured to sense wheel slippage and the control circuitry may be further configured to receive a signal from the at least one sensor, detect that wheel slippage is occurring, and activate a clutch assembly, a differential assembly, or a combination thereof in response to detecting that wheel slippage is occurring. For example, a sensor may detect shaft speed (e.g., an output shaft speed, as measured by an encoder) or output torque (e.g., an output shaft torque, or a motor torque). In some embodiments, the drive system may include an accelerator pedal configured to indicate a desired speed (e.g., by being depressed by a user), and the processing equipment may receive a signal from the accelerator pedal, determine a speed parameter based on the signal, and activate one or more clutch assemblies, one or more differential assemblies, one or more motors, or a combination thereof, if the speed parameter is above a threshold. For example, if a user "floors" the accelerator pedal (e.g., more than <NUM>% demand), the control circuitry may activate the clutch assemblies and differential assembly to lock the output shafts of a drive axis together. In some embodiments, the control circuitry may activate and deactivate a clutch assembly or differential assembly based on road conditions (e.g., icy roads, puddles, high winds), a drive mode (e.g., an off-road mode, a sport mode, or a traction mode), any other suitable criterion, or any combination thereof.

In some embodiments, one or more brackets, affixed at one or more locations, may be used to rigidly connect the two motors of the dual drive unit, two power transfer mechanism housings of the dual drive unit, or both, to ensure that all the components of the dual drive unit act as a single rigid body under normal operating conditions. In some embodiments, a boss, a tab, or other suitable feature may be included on a housing to aid in mounting.

In some embodiments, one or more drive units may be included in a vehicle. For example, Tables 2a and 2b includes some illustrative drive modes in accordance with the present invention. The four illustrative drive modes included in Table <NUM> correspond to a single drive axis, and may applied to each drive axis (e.g., independent of each other or dependent on each other). To illustrate, torque vectoring mode may allow fully independent wheel authority, hyper-mile mode may allow for a single motor to drive the drive axis (e.g., single motor propulsion differentiated to two wheels), locked mode allows for twice peak torque of either motor to be.

provided to a single wheel (e.g., a wheel with traction), and neutral mode allows for flat towing (e.g., no active torque is provided to the output shafts by the motors). In some embodiments, a center disconnecting differential is engaged to motor one (e.g., the left motor is as illustrated in <FIG>, and <FIG>), and motor two (e.g., the other motor) is quickly engaged to provide differential torque left-to-right. For example, this may be used to quickly provide a transition to torque vectoring from hyper-mile mode (e.g., single motor mode to a two-motor mode). As illustrated in Tables 2a and 2b, the output gear (e.g., and corresponding halfshaft) interfaced to the casing of the center disconnecting differential may be referred to herein as "left (L)" for "<NUM>" while the other output gear (e.g., and corresponding halfshaft) may be referred to herein as "right (R)" or "<NUM>.

<FIG> is a flowchart of an illustrative process <NUM> for managing an electric vehicle drivetrain, in accordance with some embodiments of the present invention. Process <NUM> may be implemented by electric vehicle <NUM> of <FIG>, which may include any suitable drive system such as those illustrated in <FIG>. For example, control circuity <NUM> may execute computer instructions to control one or more clutch actuators (e.g., for one or more drive axes), one or more differential actuators (e.g., for one or more drive axes), receive sensor signals from one or more sensors, retrieve reference information, any other suitable function, or any combination thereof to implement process <NUM>. In some embodiments, for example, the system implements an application that includes computer-executable instructions stored on non-transitory computer-readable media.

At step <NUM>, the system determines a drive mode for each of one or more drive axes. In some embodiments, the system selects a drive mode from among a plurality of drive modes (e.g., such as the drive modes illustrated in Tables 2a and 2b). The system may determine the drive mode based on a torque command, a current command, a speed (e.g., a wheel speed, a shaft speed, a gear speed, or a relative speed thereof), an energy consumption metric, an energy storage metric (e.g., a state of charge of battery system <NUM> of <FIG>), a user input received at input interface <NUM>, reference information (e.g., stored in a database or otherwise in memory), any other suitable information, or any combination thereof. The system may implement, or take as input, sensor input, user input, reference information, executable instructions, logic commands, any other suitable information or instruction, or any combination thereof.

In some embodiments, at step <NUM>, the system takes as input one or more sensor signals such as current signals (e.g., current in a DC bus, current in one or more motor phases), voltage signals (e.g., voltage across a DC bus, voltage across one or more motor phases), rotational position information (e.g., angular position, speed, or acceleration of a wheel, shaft, or gear), battery pack information (e.g., state of charge, estimated remaining battery life, fault information, usage information, energy consumption rate), pedal position information (e.g., from a driver controlled foot pedal for acceleration or braking), reference settings stored in memory, any other suitable information, or any combination thereof. In some embodiments, the system receives an input selection from input interface <NUM> indicating the user has selected a particular drive mode (e.g., using a turnable knob, touchscreen, push button, voice command, or any other suitable input type). In some embodiments, at step <NUM>, the system may identify a drive mode. For example, the system may identify fully locked mode (e.g., and proceed to step <NUM>) when selected by the user, when the vehicle is traveling along a straight path, when the vehicle has consistent grip at both wheels of a drive axis, when maximum or an otherwise large amount of acceleration is desired, or based on any other suitable criterion or combination thereof. In a further example, the system may identify a single motor mode (e.g., and proceed to step <NUM>) when selected by the user, when the vehicle is traveling a long distance, when the vehicle has consistent grip at both wheels of a drive axis, when maximum or an otherwise large amount of acceleration is not required, or based on any other suitable criterion or combination thereof. In a further example, the system may identify a torque vectoring mode (e.g., and proceed to step <NUM>) when selected by the user, when the vehicle is traveling off-road, when the vehicle has inconsistent grip at both wheels of a drive axis, when road conditions are dynamic or slippery, when maximum or an otherwise large amount of acceleration is intermittently required, when a tank turn is desired, or based on any other suitable criterion or combination thereof. In a further example, the system may identify a neutral mode (e.g., and proceed to step <NUM>) when selected by the user, when the vehicle is traveling a long distance, when road conditions are consistent and non-slippery, when maximum or an otherwise large amount of acceleration is not required, or based on any other suitable criterion or combination thereof.

At step <NUM>, the system achieves a fully locked mode. For example, the drive axis in the fully locked mode is driven by both motors (e.g., the vehicle may be either front wheel drive, rear wheel drive, or both). In some embodiments, at step <NUM>, the system engages or causes to be engaged the first clutch, engages or causes to be engaged the second clutch, engages or causes to be engaged the differential, and controls rotation of the first motor, the second motor, or both. For example, the system may apply current to phases of either or both the first motor and the second motor to generate torque at the fully locked output, which drives both wheels at the same angular rotation (e.g., although not necessarily the same torque). To illustrate, any of the first clutch, the second clutch, and the differential may be configured to be engaged without input (e.g., normally engaged), disengaged without input (e.g., normally disengaged), or require input to be affirmatively either engaged or disengaged. In some embodiments, step <NUM> includes generating and transmitting a signal to an actuator of the first clutch assembly, the second clutch assembly, the differential assembly, or a combination thereof. In an illustrative example, a fully locked mode is illustrated in <FIG> and <FIG>.

At step <NUM>, the system achieves a single motor mode. For example, the drive axis in the single motor mode is driven by a single motor (e.g., the vehicle may be either front wheel drive, rear wheel drive, or both). In some embodiments, at step <NUM>, the system disengages or causes to be disengaged the first clutch, disengages or causes to be disengaged the second clutch, engages or causes to be engaged the differential, and controls rotation of the first motor. For example, the system may allow the second motor to freewheel without electric power input, mechanically lock the motor in place, or otherwise not provide phase current to the second motor. To illustrate, any of the first clutch, the second clutch, and the differential may be configured to be engaged without input (e.g., normally engaged), disengaged without input (e.g., normally disengaged), or require input to be affirmatively either engaged or disengaged. In some embodiments, step <NUM> includes generating and transmitting a signal to an actuator of the first clutch assembly, the second clutch assembly, the differential assembly, or a combination thereof. In an illustrative example, a single motor mode is illustrated in <FIG> and <FIG>.

At step <NUM>, the system achieves a torque vectoring mode. For example, the drive axis in the torque vectoring mode allows both wheels to be controlled independently (e.g., the vehicle may be front wheel drive, rear wheel drive, or both). In some embodiments, at step <NUM>, the system engages or causes to be engaged the first clutch, engages or causes to be engaged the second clutch, disengages or causes to be disengaged the differential, and controls rotation of both the first motor and the second motor. For example, the system may provide the same torque, or different torque to each wheel of the drive axis by providing currents to the phases of the first and second motor. To illustrate, any of the first clutch, the second clutch, and the differential may be configured to be engaged without input (e.g., normally engaged), disengaged without input (e.g., normally disengaged), or require input to be affirmatively either engaged or disengaged. In some embodiments, step <NUM> includes generating and transmitting a signal to an actuator of the first clutch assembly, the second clutch assembly, the differential assembly, or a combination thereof. In an illustrative example, a torque vectoring mode is illustrated in <FIG> and <FIG>.

At step <NUM>, the system achieves a neutral mode. For example, the drive axis in the neutral mode is towed by the other drive axis (e.g., the vehicle is either front wheel drive or rear wheel drive but not both). In some embodiments, at step <NUM>, the system disengages or causes to be disengaged the first clutch, disengages or causes to be disengaged the second clutch, disengages or causes to be disengaged the differential. In some embodiments, at step <NUM>, the system allows both the first motor and the second motor to freewheel (e.g., without electric power input). For example, the system may provide the same torque, or different torque to each wheel of the drive axis by providing currents to the phases of the first and second motor. To illustrate, any of the first clutch, the second clutch, and the differential may be configured to be engaged without input (e.g., normally engaged), disengaged without input (e.g., normally disengaged), or require input to be affirmatively either engaged or disengaged. In some embodiments, step <NUM> includes generating and transmitting a signal to an actuator of the first clutch assembly, the second clutch assembly, the differential assembly, or a combination thereof.

At step <NUM>, the system updates the drive mode for the one or more drive axes. For example, in some embodiments, the system updates the drive mode for each drive axis. In a further example, in some embodiments, the system updates the drive mode for each drive axis having a differential assembly. In a further example, in some embodiments, the system updates the drive mode for a particular drive axis. The system may update the drive mode at a predetermined frequency, a frequency dependent on operating parameters (e.g., vehicle speed, shaft speed, gear speed), in response to an event (e.g., a change in operating parameter, an input received at an input interface),.

In an illustrative example, referencing a vehicle having two drive axes (e.g., front and rear drive units), several vehicle modes are achievable. For example, Table <NUM> shows several configurations, which may be generated by combining Tables <NUM> and <NUM>. Some of the configurations Table <NUM> may be inaccessible for drive axes without dual clutches to decouple output shafts from output gears. For example, the drive units of the present invention may be included at a front drive axis, a rear drive axis, or both, with the particular arrangement governing which configurations are accessible.

By implementing a differential between the output gears of a front or rear drive unit, and having selective clutches to vary torque paths, the system is able to achieve powering both wheels of a drive axis with a single motor and/or gearset. For example, the system may achieve <NUM>% improvement or more in overall range of the vehicle in single motor mode. In a further example, locked mode may allow an additional <NUM>% range improvement through the ability to lower the torque output of the motor and gearbox while maintaining high peak torque per wheel by locking the differential. In a further example, the neutral is achieved by disconnecting both wheels, which may be advantageous for service or flat towing a vehicle (e.g., behind a truck or recreational vehicle). The configurations of the present invention may allow for flexibility in drive mode as well as significant range improvement over other two or three motor vehicle architectures.

Claim 1:
A drive system (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) of a vehicle (<NUM>) comprising,
a first output gear (<NUM>) driven by a first motor;
a first clutch assembly (<NUM>, <NUM>) configured to couple and decouple the first output gear from a first halfshaft (<NUM>) connectable to a first wheel;
a second output gear (<NUM>) driven by a second motor;
a second clutch assembly (<NUM>, <NUM>) configured to couple and decouple the second output gear from a second halfshaft (<NUM>) connectable to a second wheel; and
a center disconnecting differential configured to couple the first output gear to the first halfshaft and to the second halfshaft;
the drive system further comprising control circuitry (<NUM>), wherein:
the first clutch assembly comprises a first actuator (<NUM>) coupled to the control circuitry;
the second clutch assembly comprises a second actuator (<NUM>) coupled to the control circuitry;
the drive system comprises a third actuator (<NUM>) coupled to the control circuitry and configured to engage and disengage the first output gear and a differential casing (<NUM>); and
the control circuitry is configured to actuate and de-actuate each of the first actuator, the second actuator, and the third actuator; wherein the control circuitry is configured to:
achieve a first drive mode wherein the first clutch assembly is engaged, the second clutch assembly is engaged, and the center disconnecting differential is disengaged;
achieve a second drive mode wherein the first clutch assembly is engaged, the second clutch assembly is engaged, and the center disconnecting differential is engaged and configured so that the first and second halfshafts are not free to rotate independently; and
achieve a third drive mode wherein the first clutch assembly is disengaged, the second clutch assembly is disengaged, and the center disconnecting differential is engaged.