WO2016014156A2

WO2016014156A2 - Vehicle dual differential assembly with disconnect capabilities

Info

Publication number: WO2016014156A2
Application number: PCT/US2015/034693
Authority: WO
Inventors: Jason J. WOZNIAK; Rory M. JOHNSON
Original assignee: Gkn Driveline North America, Inc.
Priority date: 2014-06-06
Filing date: 2015-06-08
Publication date: 2016-01-28
Also published as: WO2016014156A3

Abstract

A vehicle dual differential assembly can be equipped in an all-wheel drive (AWD) automotive driveline for performing differential functionalities between front and rear axles, and between a pair of axle sideshafts. The vehicle dual differential assembly includes a housing, a first differential assembly, a second differential assembly, and a disconnect device. The first differential assembly is located in the housing and has a first differential gear set. The second differential assembly is located in the housing and has a second differential gear set. The disconnect device is actuated between a connected state and a disconnected state.

Description

VEHICLE DUAL DIFFERENTIAL ASSEMBLY WITH

DISCONNECT CAPABILITIES

REFERENCE TO COPENDING APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application Serial No. 62/008,537 filed June 6, 2014, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates generally to differential assemblies used in vehicles, and more particularly to dual differential assemblies with disconnect capabilities.

BACKGROUND

In general, vehicle drivelines transmit torque from a vehicle's engine to its wheels. Automotive drivelines conventionally include a differential assembly equipped between sideshafts of a front axle, between sideshafts of a rear axle, or between sideshafts of both axles. Each axle typically includes a left sideshaft and a right sideshaft. The differential assembly allows wheels on one sideshaft to spin faster or slower than wheels on the other sideshaft. This occurs, for instance, when an automobile is turning a corner. The differential assembly also apportions driven torque between the sideshafts. All-wheel drive (A WD) drivelines conventionally include an additional differential assembly between its front and rear axles to perform similar functions— this is frequently referred to as a center differential. Furthermore, some automotive drivelines are equipped with disconnect capabilities in which disconnected components are no longer driven to transmit torque between them. The capabilities can preclude driven torque in regions of the automotive drivelines not needing torque transmission at a particular time. For instance, on-demand AWD drivelines do not always transmit torque among all of its shafts. And the non-torque-transmitting shafts are disconnected and do not spin like they would when the shafts are connected. Disconnect capabilities have been shown to increase fuel mileage, reduce emissions, and provide yet other performance improvements.

SUMMARY

In one implementation, a vehicle dual differential assembly may include a housing, a first differential assembly, a second differential assembly, and a disconnect device. The housing may be engaged by an input. The first differential assembly may be located in the housing, and may have a first differential gear set that includes an output gear. The second differential assembly may be located in the housing, and may have a second differential gear set. The disconnect device may be coupled to the output gear of the first differential gear set. The disconnect device may have a connected state in which the output gear engages an input of a vehicle power transfer unit. And the disconnect device may have a disconnected state in which the output gear is disengaged from the input of the vehicle power transfer unit.

In another implementation, a vehicle dual differential assembly may include a housing, a first differential assembly, a second differential assembly, and a disconnect device. The first differential assembly may be located in the housing and may have a first differential gear set. The second differential assembly may be located in the housing and may have a second differential gear set. The disconnect device may include a collar. The collar may have a first set of splines that mates with a second set of splines of the first differential assembly in order to couple the disconnect device and the vehicle dual differential assembly together. In a connected state, the first differential assembly may engage an input of a vehicle driveline component via the collar. In a disconnected state, the first differential assembly may engage the housing via the collar. Between the connected and disconnected states, the collar may slide about the coupling at the first and second sets of splines.

In yet another implementation, a vehicle dual differential assembly may include a housing, a first differential assembly, a second differential assembly, and a disconnect device. The housing may have a first set of teeth. The first differential assembly may be located in the housing and may include an output gear. The output gear may have a first set of splines. The second differential assembly may be located in the housing. The disconnect device may include a collar. The collar may have a second set of splines, a second set of teeth, and a third set of teeth. The first set of splines of the output gear and the second set of splines of the collar may mate with each other in order to couple the output gear and the collar together. In a connected state, the third set of teeth of the collar and the fourth set of teeth of an input of a vehicle driveline component may mesh with each other. In a disconnected state, the second set of teeth of the collar and the first set of teeth of the housing may mesh with each other. And between the connected and disconnected states, the collar slides about the coupling at the first and second sets of splines. BRIEF DESCRIPTION OF THE DRAWINGS The following detailed description of an embodiment and best mode will be set forth with reference to the accompanying drawings, in which:

Figure 1 is a schematic view of an embodiment of a vehicle driveline;

Figure 2 is a sectional view of an embodiment of a dual differential assembly that can be equipped in the vehicle driveline of figure 1 , the dual differential assembly having a disconnect device set in a connected state;

Figure 3 is a sectional view of the dual differential assembly of figure 2, with the disconnect device set in a disconnected state;

Figure 4 is a segmented view of another embodiment of a disconnect device, with the disconnect device set in a third state;

Figure 5 is a segmented view of another embodiment of a disconnect device, with the disconnect device set in a fourth state;

Figure 6 is a segmented view of another embodiment of a disconnect device, with the disconnect device set in a connected state;

Figure 7 is a segmented view of the disconnect device of figure 6, with the disconnect device set in a disconnected state;

Figure 8 is a segmented view of another embodiment of a disconnect device, with the disconnect device set in a connected state;

Figure 9 is a segmented view of the disconnect device of figure 8, with the disconnect device set in a disconnected state;

Figure 10 is a segmented view of another embodiment of a disconnect device, with the disconnect device having a synchronizer;

Figure 11 is a segmented view of the disconnect device of figure 10, with the synchronizer in a different state of operation; and Figure 12 is a segmented view of the disconnect device of figure 10, with the synchronizer in yet another state of operation.

DETAILED DESCRIPTION

Referring in more detail to the drawings, a dual differential assembly 10 can be equipped in an all-wheel drive (A WD) automotive driveline for performing differential functionalities between front and rear axles, and between a pair of axle sideshafts. The dual differential assembly 10 includes a disconnect device 12 for disengaging an output of the assembly from an input 14 of a power transfer unit (PTU, also known as a power take-off unit) also provided in the AWD automotive driveline. In some AWD automotive drivelines, the dual differential assembly 10 with the disconnect device 12 eliminates the need for disconnect capabilities in the PTU. It can also facilitate the use of non-friction-based disconnect capabilities downstream of the PTU, such as in rear drive modules or rear drive units (RDUs) in the AWD automotive driveline. Dog clutches and spline clutches are examples of non-friction-based disconnects. Friction-based disconnects have been shown to exhibit limited performance in some circumstances due to their thermal capacities, and hence are not always desirable in some applications.

Figure 1 depicts one example of an AWD automotive driveline 11 that can be equipped with the dual differential assembly 10. Although figure 1 does not precisely depict the dual differential assembly 10, in installation the dual differential assembly could be situated in the region generally denoted by the arrowed line D and could be located within a transaxle; still, in other examples the dual differential assembly could be installed at other regions of the AWD automotive driveline 11. In other embodiments, the AWD automotive driveline 11 could have different architectures and components than illustrated in the figure. In the embodiment presented by figure 1, the AWD automotive driveline 11 includes an engine 13, a transmission 15, a power transfer unit (PTU) 17, a propshaft 19, a rear drive unit (RDU) 21, four sideshafts 23, and four wheels 25. Skilled artisans will generally appreciate how these components operate in use.

In general, the dual differential assembly 10 can have different designs and constructions depending upon, among other possible influences, the architecture of the larger AWD automotive driveline, upstream and downstream driveline components, packaging requirements, and torque output demands. In the embodiment of figures 2 and 3, the dual differential assembly 10 includes a housing 16, a first differential assembly 18, a second differential assembly 20, and the disconnect device 12.

The housing 16 supports the first and second differential assemblies 18, 20 inside of its structure. Oil can also be held inside of the housing 16 for lubricating components of the first and second differential assemblies 18, 20; the oil can flow in and out of the housing in some examples. In the embodiment presented here, the housing 16 includes a first piece 22 and a second piece 24 that can be attached together by bolting or by another attachment technique. The first piece 22 has a generally cylindrical construction with a flange 26 at one end and a sleeve or journal 28 at its other end. The journal 28 has a set of teeth 30 (also referred to as first set of teeth) projecting axially outwardly with respect to the cylindrical shape of the journal. The teeth 30 constitute a terminal end of the journal 28 and constitute a face spline of the journal. The teeth 30 span continuously around the circumference of the journal 28 at the terminal end. The teeth 30 interact with the disconnect device 12, as subsequently described. The second piece 24 has more of a disk-like or annular construction compared to the first piece 22. Like the first piece 22, the second piece 24 has a sleeve or journal 32 at one of its ends. The journal 32 receives insertion of one of the sideshafts 23 such as a front axle sideshaft, and is received in a bearing (not shown) that helps support the dual differential assembly 10. Further, the housing 16 can carry an input gear like a ring gear at the flange 26 and at the radially-outermost region of the second piece 24 via bolting through bolt holes 34 or via another attachment technique. In operation, the ring gear can be engaged and driven by an upstream geartrain input that is itself driven by the engine 13 of the AWD automotive driveline 11. The upstream geartrain input can be a part of the transmission 15. When driven, the housing 16 rotates about an axis A.

The first differential assembly 18 performs differential functionalities between the front and rear axles of the AWD automotive driveline. Torque is apportioned between the front and rear axles via the first differential assembly 18, and the axles can rotate at different speeds relative to each other. In this sense, the first differential assembly 18 serves as a center differential in the AWD automotive driveline. The first differential assembly 18 has a set of gears that interact with one another to carry out the assembly's functionalities. The set of gears can vary. In the embodiment presented in the figures, the first differential assembly 18 has a first differential gear set 36 that includes multiple differential gears in the form of pinion gears 38, a first output gear 40, a second output gear 42, and a carrier 44.

The pinion gears 38 rotate about pinion shafts 46 carried by the housing 16. There can be four individual pinion gears 38, three of them, one pinion gear, or another quantity. In this embodiment, the pinion gears 38 are provided as spur gears with spur teeth, but could be provided as another type of gear. The pinion gears 38 engage the first and second output gears 40, 42. The first output gear 40 transmits torque to a first axle such as the front axle of the AWD automotive driveline 11 , and rotates about the axis A. Here, the first output gear 40 is provided as a crown gear with crown teeth, but could be provided as another type of gear. The first output gear 40 also serves to support components of the second differential assembly 20, as described more below.

The second output gear 42 transmits torque to a second axle such as the rear axle of the AWD automotive driveline 11 , and rotates about the axis A. Like the first output gear 40, the second output gear 42 is provided as a crown gear with crown teeth, but could be provided as another type of gear. The second output gear 42 has a sleeve 48 that receives insertion of an axle sideshaft such as a front axle sideshaft, and is overlapped across part of its axial extent by the journal 28 of the housing 16. At its outer surface, the sleeve 48 has a set of splines 50 (also referred to as first set of splines) projecting radially outwardly relative to the axis A. The splines 50 span continuously around the circumference of the sleeve 48. The carrier 44 seats and supports the pinion gears 38, and could be a unitary part of the housing 16 or could be a discrete part.

The second differential assembly 20 performs differential functionalities between the sideshafts 23, such as the pair of front axle sideshafts, of the AWD automotive driveline 11. Torque is apportioned between the front axle sideshafts via the second differential assembly 20, and the front axle sideshafts can rotate at different speeds relative to each other. The second differential assembly 20 has a set of gears that interact with one another to carry out the assembly's functionalities. The set of gears can vary. In the embodiment presented in the figures, the second differential assembly 20 has a second differential gear set 52 that includes a pair of differential gears in the form of pinion gears 54, a pin 56, and a first sideshaft gear 58 and a second sideshaft gear 60.

The pinion gears 54 rotate about an axis of the pin 56 which can lie orthogonal relative to the axis A. Because the pin 56 is carried by the first output gear 40, the pinion gears 54 also rotate about the axis A as the first output gear rotates. As illustrated in the sectional profiles of figures 2 and 3, on one side the pinion gears 54 are seated against the first output gear 40. In operation, the pinion gears 54 engage the first and second sideshaft gears 58, 60. The first sideshaft gear 58 receives insertion of one of the sideshafts 23 such as a first front axle sideshaft, and is mated with the first front axle sideshaft via a sp lined coupling. In this embodiment, the first sideshaft gear 58 is provided as a crown gear with crown teeth, but could be provided as another type of gear. Likewise, the second sideshaft gear 60 receives insertion of one of the sideshafts 23 such as a second front axle sideshaft, is mated therewith via a splined coupling, and is provided as a crown gear in this embodiment but could be provided as another type of gear.

In general, the disconnect device 12 connects and disconnects the first differential assembly 18 to and from the input 14 of the PTU 17, or to and from an input of another AWD automotive driveline component. The disconnect device 12 can have different designs and constructions for performing this function, and can have additional functionalities as described below. In the embodiment presented in the figures, the disconnect device 12 includes a collar 62. The collar 62 has a generally cylindrical shape, and on its inner surface the collar has a set of splines 64 (also referred to as second set of splines) that mate with the splines 50 of the second output gear 42 for a splined coupling therebetween. In other embodiments not depicted in the figures, the splines 50 could project radially inwardly from an inner surface of the second output gear 42, and the splines 64 could project radially outwardly from an outer surface of the collar 62; still, the splined coupling between the second output gear 42 and collar 62 could be effected by other constructions. The splined coupling provides co-rotation between the collar 62 and second output gear 42, while permitting axial sliding of the collar relative to the sleeve 48 of the second output gear. The splines 64 span continuously around the circumference of the collar 62 at the inner surface.

At one axial end, the collar 62 has a set of teeth 66 (also referred to as second set of teeth) projecting axially outwardly to constitute an axial terminal end of the collar. The teeth 66 constitute a first face spline of the collar 62. And at its other axial end, the collar 62 has another set of teeth 68 (also referred to as third set of teeth) projecting axially outwardly to constitute the other axial terminal end of the collar. The teeth 68 constitute a second face spline of the collar 62. Both teeth 66, 68 span continuously around the circumference of the collar 62 at their respective axial terminal ends. In operation, the teeth 66 mesh with the teeth 30 of the housing 16 upon command, and the teeth 68 mesh with a set of teeth 70 (also referred to as fourth set of teeth) of the PTU's input 14 upon command. The teeth 70 constitute a face spline of the PTU's input 14. The teeth 70 can be complementary to the teeth 68 so they can mesh. In the embodiment here, the teeth respectively mesh and unmesh to furnish a dog clutch engagement and disengagement.

In operation in one embodiment, the disconnect device 12 moves between a connected state as depicted in figure 2 and a disconnected state as depicted in figure 3. Movement between the states can be carried out by different actuation approaches. These include electric actuation, hydraulic actuation, electromagnetic actuation, and pneumatic actuation; still, other actuation types and techniques are possible. And depending on the approach, the actuation can include different components such as a shift fork, a ball cam mechanism, a piston, or other items and mechanisms.

Referring particularly to figure 2, in the connected state the teeth 68, 70 are meshed together and the second output gear 42 is engaged with the PTU's input 14 by way of the collar 62. Torque is therefore transmitted from the second output gear 42 of the first differential assembly 18, through the disconnect device 12, and to the PTU 17 where the torque is further transmitted downstream the PTU to the propshaft 19 and ultimately to an axle of the AWD automotive driveline 11 such as the rear axle sideshafts 23. Torque transmission is apportioned between the front and rear axles according to the selected geartrain of the first differential assembly 18, and the AWD automotive driveline 11 is in its all-wheel drive mode. Furthermore, in the connected state, the teeth 30, 66 are unmeshed and the second output gear 42 is hence disengaged from the housing 16 at that location.

Referring now to figure 3, when the disconnect device 12 is commanded to its disconnect state and actuated, the collar 62 slides axially and linearly along the splines 50 of the sleeve 48 (from figure 2 to figure 3, the collar 62 slides right to left). The teeth 66, 30 are meshed together and the disconnect device 12 is brought to the disconnected state. In this state, the second output gear 42 is engaged with the housing 16 by way of the collar 62. The teeth 68, 70, on the other hand, are unmeshed and the second output gear 42 is disengaged from the PTU's input 14. Torque transmission is now apportioned one-hundred percent (100%) to the second differential assembly 20 and zero percent (0%) to the first differential assembly 18, and the AWD automotive driveline 11 is in its two-wheel drive mode.

In other embodiments, the disconnect device 12 can move to yet additional states. Referring to figure 4, in a third state, for instance, the collar 62 is moved approximately midway between the journal 28 and the PTU's input 14. Here, the teeth 66, 68 of the collar 62 are elongated in their respective axial directions compared to their length in the embodiment of figures 2 and 3. As illustrated in figure 4, at the same time the teeth 66 mesh with the teeth 30, and the teeth 68 mesh with the teeth 70. In the third state, the second output gear 42 is engaged with both the PTU's input 14 and the housing 16, and the front and rear axles are in a so-called locked condition. In the locked condition, the front axle is spline-locked to the rear axle. The locked condition may be desirable when the accompanying automobile is driven off-road. The third state may also be employed for low speed on-the-fly shifting. In some instances, the third state facilitates the use of friction-based engagement capabilities in a rear drive module like the RDU 21, since the friction- based engagement capabilities can slip at varying rates and thereby apportion front and rear torque bias in real-time.

Referring now to figure 5, in a fourth state the collar 62 is moved approximately midway between the journal 28 and the PTU's input 14. Here, all of the teeth are unmeshed and the components are consequently disengaged— that is, the teeth 30, 66 are unmeshed and the second output gear 42 is disengaged from the housing 16, and the teeth 68, 70 are unmeshed and the second output gear 42 is disengaged from the PTU's input 14. The fourth state constitutes a so-called neutral condition. In the neutral condition, the dual differential assembly 10 and the PTU 17 are disconnected and no torque is transmitted therebetween. The sideshafts 23 are able to spin, while disconnected components like the PTU 17 and its internal shafts and gears can remain substantially static. The disconnect device 12 can be set in the fourth state when the accompanying automobile is experiencing a so-called flat tow in which all of the wheels 25 are rolling over the ground as the automobile is being hauled by another vehicle.

In other embodiments, the teeth involved in the connected and disconnected actions can be designed and constructed in different ways. For example, in the embodiment of figures 6 and 7, the different sets of teeth project radially with respect to the axis A, instead of axially as in previous embodiments. Figure 6 depicts the connected state, and figure 7 depicts the disconnected state; and although not depicted, in some embodiments the disconnect device 12 of figures 6 and 7 could also move to the third and fourth states as previously described. In the embodiment of figures 6 and 7, the journal 28 has a first set of teeth 72 projecting radially outwardly relative to the cylindrical shape of the journal. The teeth 72 are situated at the terminal end of the journal 28 and span continuously around the circumference of the journal. The collar 62 of the disconnect device 12 has a second set of teeth 74 projecting radially inwardly. The teeth 74 are situated at an overhanging portion of the collar 62 and span continuously around the collar. The collar 62 has a third set of teeth 76 projecting radially inwardly, situated at an opposite overhanging portion of the collar, and spanning continuously around the collar. And the PTU's input 14 has a fourth set of teeth 78 projecting radially outwardly and situated at the terminal end of the input and spanning continuously around the circumference of the input. In operation, the teeth 72 mesh with the teeth 74 as shown in figure 7, and the teeth 76 mesh with the teeth 78 as shown in figure 6.

Still, in other embodiments, teeth need not be involved in the connected and disconnected actions. For example, in the embodiments of figures 8 and 9, the components lack teeth, and instead the connected and disconnected states are effected via frictional engagement. In the connected state of figure 8, a first face 84 (figure 9) of the collar 62 abuts and comes into direct surface-to-surface contact with a second face 86 (figure 9) of the PTU's input 14. The friction generated between the first and second faces 84, 86 can serve to synchronize the rotations of the disconnect device 12 and the PTU's input 14, and ultimately serves to transmit torque from the second output gear 42 of the first differential assembly 18, through the disconnect device 12, and to the PTU 17. The first and/or second faces 84, 86 can carry a friction material such as a carbon fiber material, can have a friction coating applied thereto, or the frictional engagement can simply involve metal-to-metal engagement without friction materials or coatings. In the disconnected state of figure 9, a third face 82 (figure 8) of the collar 62 abuts and comes into direct surface-to-surface contact with a fourth face 80 (figure 8) of the journal 28. As before, the friction generated between the third and fourth faces 82, 80 can serve to synchronize the rotations of the disconnect device 12 and the housing 16, and ultimately serves to transmit torque from the second output gear 42, through the disconnect device, and to the housing. The third and/or fourth faces 82, 80 can carry a friction material such as a carbon fiber material, can have a friction coating applied thereto, or the frictional engagement can simply involve metal-to-metal engagement without friction materials or coatings. The frictional engagement between the faces 80, 82, 84, 86 can be carried out under wet conditions or dry conditions and with or without lubrication; for example, when the dual differential assembly 10 is located within a transaxle having a sump containing lubrication, the frictional engagement may occur under wet conditions.

In yet other embodiments, including the embodiments detailed elsewhere in this description, the dual differential assembly 10 can include one or more synchronizers the work to synchronize the rotational speeds of the components as they engage while being brought to the connected and disconnected states. Synchronization can facilitate on-the-fly shifting to the connected and disconnected states. In the embodiment of figures 10, 11, and 12, a first synchronizer 88 is equipped between the disconnect device 12 and the journal 28, and a second synchronizer 90 is equipped between the disconnect device 12 and the PTU's input 14. The first synchronizer 88 synchronizes rotational speeds between the second output gear 42 and the journal 28 as the disconnect device 12 is brought to the disconnected state. Skilled artisans will appreciate the exact components and functionality involved in these types of synchronization events. In the example presented here, the first synchronizer 88 includes a first extension 92, a first cone 94, and a first spring 96. The first extension 92 spans from the journal 28 and constitutes the terminal end of the journal. A working face of the first extension 92 can carry a friction material, can have a friction coating, or can have neither. The first cone 94 can have a splined coupling, a keyed coupling, or another type of coupling with the collar 62, and can slide thereat relative to the collar. A working face of the first cone 94 can carry a friction material, can have a friction coating, or can have neither. The first spring 96 serves to bias the first cone 94 away from the collar 62, and can be a coil spring, a wave spring, or another type of spring. Still, the first synchronizer 88 could have other and/or different components than those depicted and described here.

The second synchronizer 90 includes a second extension 98, a second cone 100, and a second spring 102. The second extension 98 spans from the PTU's input 14 and constitutes the terminal end of the input. A working face of the second extension 98 can carry a friction material, can have a friction coating, or can have neither. The second cone 100 can have a splined coupling, a keyed coupling, or another type of coupling with the collar 62, and can slide thereat relative to the collar. A working face of the second cone 100 can carry a friction material, can have a friction coating, or can have neither. The second spring 102 serves to bias the second cone 100 away from the collar 62, and can be a coil spring, a wave spring, or another type of spring. Still, the second synchronizer 90 could have other and/or different components than those depicted and described here.

The first and second synchronizers 88, 90 function similarly in operation, and hence only the operation of the second synchronizer is described here with reference to figures 11 and 12. As the collar 62 is moving toward the PTU's input 14, the working surfaces of the second extension 98 and the second cone 100 come into surface-to-surface contact before the teeth 76 and teeth 78 mesh with each other— this is perhaps depicted best by figure 11. The surface-to-surface contact brings the rotational speeds of the second output gear 42 and the PTU's input 14 in correspondence with each other. Upon farther movement, the second spring 102 yields and the teeth 76 and teeth 78 mesh together— this is perhaps depicted best by figure 12.

As noted above, the dual differential assembly 10 with the disconnect device

12 can eliminate the need for disconnect capabilities in the PTU 17. This means that the PTU 17 in the AWD automotive driveline 11 may have a simpler construction with less components. And since disconnect capabilities in PTUs have sometimes involved friction-based clutching which in some circumstances have been shown to exhibit limited heat endurance, the splined coupling and meshing teeth embodiments of the disconnect device 12 can improve disconnect performance in the AWD automotive driveline 11. The simpler construction and less components of the PTU 17 also means that the PTU can be designed and constructed to more readily satisfy packaging demands in the AWD automotive driveline 11— such packaging demands are oftentimes inflexible as set by the original equipment manufacturer. Without friction-based clutching in the PTU 17, the PTU may have a lower overall operating temperature since friction-based clutches typically generate a not insubstantial amount of heat. The lower temperatures can therefore extend the useful life of the PTU 17, and may enhance its performance capabilities. Furthermore, in the disconnected state, torque is not transmitted to components of the PTU 17 from the first differential assembly 18. The components of the PTU 17 hence do not endure torque transmission in the disconnected state. The components can therefore have an extended useful life, compared to PTU components that endure torque transmission even when accompanying disconnect capabilities are disconnected.

Moreover, the dual differential assembly 10 with the disconnect device 12 can also facilitate the use of non-friction-based disconnect capabilities in a rear drive module or RDU 21 in the AWD automotive drive line 11. Instead, dog clutches and spline clutches could be employed in the rear drive modules and the RDU 21. Dog and spline clutches have been shown to exhibit greater heat endurance than friction- based clutches in some automotive driveline applications. Previously, friction-based capabilities were needed in rear drive modules in order to accommodate axles that rotate at different speeds. But since the different speeds can be accommodated via the dual differential assembly 10 and its first and second differential assemblies 18, 20, the friction-based capabilities may not be needed at the rear drive modules. Nevertheless, friction-based clutches could still be used in rear drive modules or the RDU 21 in certain AWD automotive drivelines.

Lastly, when installed in the AWD automotive driveline 11, the dual differential 10 with disconnect device 12 could be used with, and could cooperate with, a rear drive module or unit that also has disconnect capabilities. For instance, the RDU 21 could be equipped with a sideshaft disconnect device that has a dog clutch or a spline clutch, or that otherwise uses non-friction-based clutching. Still, friction clutches are possible in the RDU 21 in some applications. Disconnect devices in the RDU 21 could yet also be situated at its pinion or ring gear. And the RDU 21 could have a synchronizer device.

It is to be understood that the foregoing description is of one or more embodiments of the invention. The invention is not limited to the particular embodiment(s) disclosed herein, but rather is defined solely by the claims below. Furthermore, the statements contained in the foregoing description relate to the disclosed embodiment(s) and are not to be construed as limitations on the scope of the invention or on the definition of terms used in the claims, except where a term or phrase is expressly defined above. Various other embodiments and various changes and modifications to the disclosed embodiment(s) will become apparent to those skilled in the art.

As used in this specification and claims, the terms "e.g.," "for example," "for instance," "such as," and "like," and the verbs "comprising," "having," "including," and their other verb forms, when used in conjunction with a listing of one or more components or other items, are each to be construed as open-ended, meaning that the listing is not to be considered as excluding other, additional components or items. Other terms are to be construed using their broadest reasonable meaning unless they are used in a context that requires a different interpretation. Furthermore, all stated values (e.g., percentages, angles, ranges, etc.) are provided for illustrative purposes only and are not meant to be limiting in nature. Those skilled in the art will appreciate that in some implementations that remain within the spirit and scope of the present invention, values other than those set forth herein may be used.

Claims

CLAIMS:

1. A vehicle dual differential assembly, comprising:

a housing engaged by an input;

a first differential assembly located in said housing and having a first differential gear set that includes an output gear;

a second differential assembly located in said housing and having a second differential gear set; and

a disconnect device coupled to said output gear of said first differential gear set, said disconnect device having a connected state in which said output gear engages an input of a vehicle power transfer unit, and said disconnect device having a disconnected state in which said output gear is disengaged from the input of the vehicle power transfer unit.

2. A vehicle dual differential assembly as set forth in claim 1, wherein, in the connected state, said output gear of said first differential gear set is disengaged from said housing.

3. A vehicle dual differential assembly as set forth in claim 1, wherein, in the disconnected state, said output gear of said first differential gear set engages said housing via said disconnect device.

4. A vehicle dual differential assembly as set forth in claim 1, wherein said disconnect device moves axially relative to an axis of rotation of said housing between the connected and disconnected states.

5. A vehicle dual differential assembly as set forth in claim 1, wherein said housing has a first set of teeth and said disconnect device has a second set of teeth, said first and second sets of teeth meshing with each other when said disconnect device is in the disconnected state.

6. A vehicle dual differential assembly as set forth in claim 5, wherein said disconnect device has a third set of teeth meshing with a fourth set of teeth of the input of the vehicle power transfer unit when said disconnect device is in the connected state.

7. A vehicle dual differential assembly as set forth in claim 6, wherein at least one of said first set of teeth, said second set of teeth, said third set of teeth, or said fourth set of teeth extends generally in an axial direction relative to an axis of rotation of said housing.

8. A vehicle dual differential assembly as set forth in claim 6, wherein at least one of said first set of teeth, said second set of teeth, said third set of teeth, or said fourth set of teeth extends generally in a radial direction relative to an axis of rotation of said housing.

9. A vehicle dual differential assembly as set forth in claim 6, wherein, when said disconnect device is in a third state, said first and second sets of teeth mesh with each other and said third and the fourth sets of teeth mesh with each other.

10. A vehicle dual differential assembly as set forth in claim 6, wherein, when said disconnect device is in a fourth state, said first and second sets of teeth are unmeshed with each other and said third and the fourth sets of teeth are unmeshed with each other.

11. A vehicle dual differential assembly as set forth in claim 1 , wherein said output gear of said first differential gear set has a first set of splines, and said disconnect device includes a collar having a second set of splines, said first and second sets of splines mating with each other to couple said output gear and said disconnect device together.

12. A vehicle dual differential assembly as set forth in claim 1, wherein, in the connected state, said disconnect device and the input of the vehicle power transfer unit engage each other via a first frictional engagement, and wherein, in the disconnected state, said disconnect device and said housing engage each other via a second frictional engagement.

13. A vehicle dual differential assembly as set forth in claim 1, further comprising at least one synchronizer located at said disconnect device for synchronizing rotations in the connected state, in the disconnected state, or in both the connected and disconnected states.

14. An all-wheel drive automotive driveline comprising the vehicle dual differential assembly of claim 1 , and further comprising a rear drive unit having non- friction-based disconnect device capabilities.

15. An all-wheel drive automotive driveline comprising the vehicle dual differential assembly of claim 1 , and further comprising a power transfer unit (PTU) that lacks a disconnect device.

16. A vehicle dual differential assembly, comprising:

a housing;

a first differential assembly located in said housing and having a first differential gear set;

a disconnect device including a collar, said collar having a first set of splines that mates with a second set of splines of said first differential assembly in order to couple said disconnect device and the vehicle dual differential assembly together, wherein, in a connected state, said first differential assembly engages an input of a vehicle driveline component via said collar, wherein, in a disconnected state, said first differential assembly engages said housing via said collar, and wherein, between the connected and disconnected states, said collar slides about the coupling at said first and second sets of splines.

17. A vehicle dual differential assembly as set forth in claim 16, wherein, when said disconnect device is in a third state, said first differential assembly engages the input of the vehicle driveline component via said collar, and, in the third state, said first differential assembly engages said housing via said collar.

18. A vehicle dual differential assembly as set forth in claim 16, wherein, when said disconnect device is in a fourth state, said first differential assembly is disengaged from the input of the vehicle driveline component, and, in the fourth state, said first differential assembly is disengaged from said housing.

19. A vehicle dual differential assembly as set forth in claim 16, further comprising at least one synchronizer located at said collar for synchronizing rotations in the connected state, in the disconnected state, or in both the connected and disconnected states.

20. A vehicle dual differential assembly, comprising:

a housing having a first set of teeth;

a first differential assembly located in said housing and including an output gear, said output gear having a first set of splines;

a second differential assembly located in said housing; and

a disconnect device including a collar, said collar having a second set of splines, a second set of teeth, and a third set of teeth, said first set of splines of said output gear and said second set of splines of said collar mating with each other to couple said output gear and said collar together, wherein, in a connected state, said third set of teeth of said collar and a fourth set of teeth of an input of a vehicle driveline component meshing with each other, wherein, in a disconnected state, said second set of teeth of said collar and said first set of teeth of said housing meshing with each other, and wherein, between the connected and disconnected states, said collar slides about the coupling at said first and second sets of splines.