Driveline disconnect with modular rear driveline module (RDM) with integrated coupling and differential control

1. A motor vehicle powertrain ( 10 ) including a secondary drive split axle for driving a pair of wheels ( 14 a , 14 b ), the improvement of the motor vehicle powertrain ( 10 ) comprising:

a rear driveline module (RDM) ( 20 , 320 ) including:

a planetary gear assembly having a ring gear ( 112 ) defining a differential axis;

a common planetary gear carrier supporting a first set and a second set of planetary gears ( 118 a , 118 b ) for rotation about the differential axis, the first and second sets of planetary gears ( 118 a , 118 b ) rotatable independently of one another;

first and second sun gears ( 126 a , 126 b ) connected to the pair of wheels ( 14 a , 14 b ), respectively, the first sun gear ( 126 a ) meshing with the first set of planetary gears ( 118 a ) for driving one of the pair of wheels ( 14 a ) and the second sun gear ( 126 b ) meshing with the second set of planetary gears ( 118 b ) for driving another of the pair of wheels ( 14 b );

a hydraulically actuated coupling clutch ( 28 ) mounted on the differential axis interposed between the pair of wheels ( 14 a , 14 b );

a single fluid pump ( 66 ) providing a source of pressurized fluid ( 62 );

a hydraulic control system ( 16 ) for selectively providing fluid communication from the single fluid pump ( 66 ) with the coupling clutch ( 28 ) for actuating the coupling clutch ( 28 ) and with a lubrication delivery system ( 50 ) for lubricating the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) on-demand from a fluid sump ( 60 ) separate from the RDM ( 20 , 320 ), thereby eliminating shearing of fluid by the ring gear ( 112 ); and

a lubrication control valve ( 80 ) for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) for lubrication when in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and at least one clutch control valve ( 70 a , 70 b , 70 c ) when in a second position.

2. The improvement of claim 1 further comprising:

a power take-off unit (PTU) ( 36 ) including a hydraulically actuated PTU coupling clutch ( 42 ) for selectively transmitting rotary power between a front driveline module and the rear driveline module ( 20 , 320 ); and

wherein the hydraulic control system ( 16 ) selectively provides fluid communication with the PTU coupling clutch ( 42 ) for actuation with pressurized fluid from the single fluid pump ( 66 ).

3. The improvement of claim 2 , wherein the at least one clutch control valve ( 70 a , 70 b , 70 c ) is a PTU clutch control valve ( 70 c ) for selectively providing fluid communication between the PTU coupling clutch ( 42 ) and the fluid sump ( 60 ) for actuation of the PTU coupling clutch ( 42 ) to a disengaged position when the PTU clutch control valve ( 70 c ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the PTU coupling clutch ( 42 ) for actuation of the PTU coupling clutch ( 42 ) to an engaged position when the PTU clutch control valve ( 70 c ) is in a second position.

4. The improvement of claim 1 , wherein the at least one clutch control valve ( 70 a , 70 b , 70 c ) is a RDM clutch control valve ( 70 a ) for selectively providing fluid communication between the coupling clutch ( 28 ) and the fluid sump ( 60 ) for actuation of the coupling clutch ( 28 ) to a disengaged position when the RDM clutch control valve ( 70 a ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the coupling clutch ( 28 ) for actuation of the coupling clutch ( 28 ) to an engaged position when the RDM clutch control valve ( 70 a ) is in a second position.

5. The improvement of claim 1 , wherein the lubrication delivery system further comprises:

a scavenging apparatus ( 56 ) scavenging fluid from the source of pressurized fluid ( 62 ) for redirecting the fluid to lube distribution passages in fluid communication with predetermined locations in the RDM ( 20 , 320 ).

6. The improvement of claim 1 , wherein the at least one clutch control valve ( 70 a , 70 b , 70 c ) selectively provides fluid communication between the at least one clutch ( 28 , 34 , 42 ) and the fluid sump ( 60 ) for actuation of the at least one clutch ( 28 , 34 , 42 ) to a disengaged position when the least one clutch control valve ( 70 a , 70 b , 70 c ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the at least one clutch ( 28 , 34 , 42 ) for actuation of the at least one clutch ( 28 , 34 , 42 ) to an engaged position when the at least one clutch control valve ( 70 a , 70 b , 70 c ) is in a second position; and

an accumulator ( 92 ) in fluid communication with the at least one clutch control valve ( 70 a , 70 b , 70 c ) for maintaining fluid pressure and volume to be supplied to the at least one clutch control valve ( 70 a , 70 b , 70 c ) of the hydraulic control system ( 16 ) when the lubrication control valve ( 80 ) is in the first position.

7. A motor vehicle powertrain ( 10 ) including a secondary drive split axle for driving a pair of wheels ( 14 a , 14 b ), the improvement of the motor vehicle powertrain ( 10 ) comprising:

a rear driveline module (RDM) ( 20 , 320 ) including:

a planetary gear assembly having a ring gear ( 112 ) defining a differential axis;

a common planetary gear carrier supporting a first set and a second set of planetary gears ( 118 a , 118 b ) for rotation about the differential axis, the first set and second set of planetary gears ( 118 a , 118 b ) rotatable independently of one another;

first and second sun gears ( 126 a , 126 b ) connected to the pair of wheels ( 14 a , 14 b ), respectively, the first sun gear ( 126 a ) meshing with the first set of planetary gears ( 118 a ) for driving one of the pair of wheels ( 14 a ) and the second sun gear ( 126 b ) meshing with the second set of planetary gears ( 118 b ) for driving another of the pair of wheels ( 14 b );

a hydraulically actuated coupling clutch ( 28 ) mounted on the differential axis interposed between the pair of wheels ( 14 a , 14 b );

a single fluid pump ( 66 ) providing a source of pressurized fluid ( 62 );

a hydraulic control system ( 16 ) for selectively providing fluid communication from the single fluid pump ( 66 ) with the coupling clutch ( 28 ) for actuating the coupling clutch ( 28 ) and with a lubrication delivery system ( 50 ) for lubricating the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ); and

a hydraulically actuated differential control clutch ( 34 ) mounted on the differential axis coaxial with and adjacent to the coupling clutch ( 28 ) for speed differentiation between the pair of wheels ( 14 a , 14 b ),

wherein the hydraulic control system ( 16 ) selectively provides fluid communication with the differential control clutch ( 34 ) for actuation with pressurized fluid from the single fluid pump ( 66 ).

8. The improvement of claim 7 , wherein the hydraulic control system ( 16 ) further comprises:

a differential clutch control valve ( 70 b ) for selectively providing fluid communication between the differential clutch ( 34 ) and a fluid sump ( 60 ) for actuation of the differential clutch ( 34 ) to a disengaged position when the differential clutch control valve ( 70 b ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the differential clutch ( 34 ) for actuation of the differential clutch ( 34 ) to an engaged position when the differential clutch control valve ( 70 b ) is in a second position; and

a lubrication control valve ( 80 ) for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) for lubrication when in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the differential clutch control valve ( 70 b ) when in a second position.

9. The improvement of claim 7 further comprising:

a power take-off unit (PTU) ( 36 ) including a hydraulically actuated PTU coupling clutch ( 42 ) for selectively transmitting rotary power between a front driveline module and the rear driveline module ( 20 , 320 ); and

wherein the hydraulic control system ( 16 ) selectively provides fluid communication with the PTU coupling clutch ( 42 ) for actuation with pressurized fluid from the single fluid pump ( 66 ).

10. The improvement of claim 9 , wherein the hydraulic control system ( 16 ) further comprises:

a differential clutch control valve ( 70 b ) for selectively providing fluid communication between the differential clutch ( 34 ) and a fluid sump ( 60 ) for actuation of the differential clutch ( 34 ) to a disengaged position when the differential clutch control valve ( 70 b ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the differential clutch ( 34 ) for actuation of the differential clutch ( 34 ) to an engaged position when the differential clutch control valve ( 70 b ) is in a second position;

a PTU clutch control valve ( 70 c ) for selectively providing fluid communication between the PTU coupling clutch ( 42 ) and the fluid sump ( 60 ) for actuation of the PTU coupling clutch ( 42 ) to a disengaged position when the PTU clutch control valve ( 70 c ) is in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the PTU coupling clutch ( 42 ) for actuation of the PTU coupling clutch ( 42 ) to an engaged position when the PTU clutch control valve ( 70 c ) is in a second position; and

a lubrication control valve ( 80 ) for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) for lubrication when in a first position and for selectively providing fluid communication between the source of pressurized fluid ( 62 ) and the differential clutch control valve ( 70 b ) and the PTU clutch control valve ( 70 c ) when in a second position.

11. A method of assembly for a motor vehicle powertrain ( 10 ) including a secondary drive split axle for driving a pair of wheels ( 14 a , 14 b ), the improvement of the motor vehicle powertrain ( 10 ) comprising:

assembling a rear driveline module (RDM) ( 20 , 320 ) including:

mounting a planetary gear assembly having a ring gear ( 112 ) defining a differential axis;

supporting a first set and a second set of planetary gears ( 118 a , 118 b ) with a common planetary gear carrier for rotation about the differential axis, the first and second sets of planetary gears ( 118 a , 118 b ) rotatable independently of one another;

connecting first and second sun gears ( 126 a , 126 b ) to the pair of wheels ( 14 a , 14 b ), respectively, the first sun gear ( 126 a ) meshing with the first set of planetary gears ( 118 a ) for driving one of the pair of wheels ( 14 a ) and the second sun gear ( 126 b ) meshing with the second set of planetary gears ( 118 b ) for driving another of the pair of wheels ( 14 b );

mounting a hydraulically actuated coupling clutch ( 28 ) on the differential axis interposed between the pair of wheels ( 14 a , 14 b );

connecting a single fluid pump ( 66 ) with a source of pressurized fluid ( 62 ) for actuation of the coupling clutch ( 28 ) and on-demand lubrication of the RDM ( 20 , 320 );

controlling fluid communication of the source of pressurized fluid ( 62 ) with a hydraulic control system ( 16 ) having clutch control valves ( 70 a , 70 b , 70 c ) selectively operated by a control system ( 88 ) for selectively providing fluid communication from the single fluid pump ( 66 ) with the coupling clutch ( 28 ) for actuating the coupling clutch ( 28 ) and with a lubrication delivery system ( 50 ) for lubricating the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) from a fluid sump ( 60 ) separate from the RDM ( 20 , 320 ), thereby eliminating shearing of fluid by the ring gear ( 112 );

selectively controlling fluid communication between the source of pressurized fluid ( 62 ) and the ring gear ( 112 ), the first and second sets of planetary gears ( 118 a , 118 b ), and the first and second sun gears ( 126 a , 126 b ) with a lubrication control valve ( 80 ) for lubrication when in a first position; and

selectively controlling fluid communication between the source of pressurized fluid ( 62 ) and at least one of the clutch control valves ( 70 a , 70 b , 70 c ) with the lubrication control valve ( 80 ) when in a second position.

12. The method of claim 11 further comprising:

mounting a hydraulically actuated differential control clutch ( 34 ) on the differential axis coaxial with and adjacent to the coupling clutch ( 28 ) for speed differentiation between the pair of wheels ( 14 a , 14 b ); and

selectively controlling fluid communication with the differential control clutch ( 34 ) for actuation with pressurized fluid from the single fluid pump with the hydraulic control system ( 16 ).

13. The method of claim 12 further comprising:

selectively transmitting rotary power between a front driveline module and the rear driveline module ( 20 , 320 ) with a power take-off unit (PTU) ( 36 ) including a hydraulically actuated PTU coupling clutch ( 42 ); and

selectively controlling fluid communication with the PTU coupling clutch ( 42 ) for actuation with pressurized fluid from the single fluid pump ( 66 ) with the hydraulic control system ( 16 ).

14. The method of claim 11 further comprising:

selectively transmitting rotary power between a front driveline module and the rear driveline module ( 20 , 320 ) with a power take-off unit (PTU) ( 36 ) including a hydraulically actuated PTU coupling clutch ( 42 ); and

selectively controlling fluid communication with the PTU coupling clutch ( 42 ) for actuation with pressurized fluid from the single fluid pump ( 66 ) with the hydraulic control system ( 16 ).

15. The method of claim 11 further comprising:

selectively controlling fluid communication between the at least one clutch ( 28 , 34 , 42 ) and the fluid sump ( 60 ) with the at least one of the clutch control valves ( 70 a , 70 b , 70 c ) for actuation of the at least one clutch ( 28 , 34 , 42 ) to a disengaged position when the at least one of the control valves ( 70 a , 70 b , 70 c ) is in a first position;

selectively controlling fluid communication between the source of pressurized fluid ( 62 ) and the at least one clutch ( 28 , 34 , 42 ) with the at least one of the clutch control valves ( 70 a , 70 b , 70 c ) for actuation of the at least one clutch ( 28 , 34 , 42 ) to an engaged position when the at least one of the clutch control valves ( 70 a , 70 b , 70 c ) is in a second position; and

maintaining fluid pressure and volume to be supplied to the at least one of the clutch control valves ( 70 a , 70 b , 70 c ) of the hydraulic control system ( 16 ) with an accumulator ( 92 ) in fluid communication with the at least one of the clutch control valves ( 70 a , 70 b , 70 c ) when the lubrication control valve ( 80 ) is in the first position.