Abstract: A work vehicle locking differential energy management system includes axle speed sensors for monitoring the rotational speeds of axle half-shafts. The axle half-shafts are coupled through a locking differential, which contains a differential clutch mechanism. A processing subsystem is configured to: (i) when the locking differential is placed in a locked state, calculate a differential lock force applied to the clutch mechanism, and calculate a differential slip speed from a disparity in the rotational speeds of the axle half-shafts; (ii) estimate an internal temperature of the clutch mechanism based, at least in part, on the differential lock force and the differential slip speed; (iii) detect differential overtemperature events during which the internal temperature of the clutch mechanism exceeds a first critical temperature threshold; and (iv) perform at least one differential overtemperature action in response to detection of a differential overtemperature event.

Abstract: Systems and methods for an interaxle differential (IAD) are provided. In one example, the IAD comprises a locking assembly that includes a friction clutch, the friction clutch includes a clutch pack that comprises plurality of plates configured to engage and disengage to inhibit and permit speed differentiation between a first axle differential and a second axle differential. The IAD further includes a supply lubrication passage that comprises an inlet that receives a lubricant from an enclosure surrounding an input gear of an axle differential and a first outlet flowing the lubricant to a gear coupled to the clutch pack.

Abstract: An electric drive axle including an electric motor, a gear arrangement, a differential, and a disconnect device at least partially disposed within a differential case. The gear arrangement is configured to produce a certain gear ratio between the electric motor and the differential.

Abstract: A vehicle differential device comprises: a differential casing rotatably disposed around a rotational axis; and a pair of side gears rotatably supported by the differential casing and supported in a thrust direction via an annular bearing surface formed in the differential casing to mesh with a pair of pinion gears. The differential casing is provided with a first lubricating oil passage formed in a circumferential direction on an outer circumferential side of the bearing surface in the differential casing, and a first guidance projection projected toward the rotational axis in the first lubricating oil passage and guiding a lubricating oil flowing in a circumferential direction in the first lubricating oil passage due to rotation of the differential casing around the rotational axis, toward a first meshing portion between a first side gear of the pair of side gears and the pinion gears.

Abstract: A differential gear device including: a differential casing; and a pair of side gears which are disposed within the differential casing such that the side gears are rotatable about the above-indicated axis and are axially opposed to each other, and such that a rotary motion of the differential casing about the above-indicated axis is transmitted to the side gears through at least one pinion gear, the differential casing having a pair of bearing portions which extend from its respective inner surfaces toward back surfaces of the respective side gears, which are coaxial with said axis and which have respective annular seating surfaces which receive axial loads from the side gears, and wherein each of the pair of bearing portions has a protrusion extending from an outer circumference of corresponding one of the annular seating surfaces in a radially outward direction of the annular seating surface.

Abstract: A disconnecting axle includes a housing assembly including a first end cap coupled to a first side of a housing member to define a clutch cavity, and a second end cap coupled to a second side of the housing member to define a differential cavity. The housing member can define a central bore, a sump, and a plurality of passages. The central bore extends axially between the clutch and differential cavities. The sump can be spaced apart from the clutch and differential cavities, and the central bore. A clutch passage couples the clutch cavity to the sump. A differential passage couples the differential cavity to the sump. A first output member of the differential extends axially within the central bore. A piston is configured to compress friction plates to selectively transmit torque. A pump can pump fluid from the sump to the cylinder to move the piston.

Abstract: A continuously variable differential gear comprising: a pair of rotating bevel gears engaged with one another via a pinion gear, each of the bevel gears including a first operating surface; an actuator, opposing ends thereof having a pair of interconnected fluid reservoirs, the actuator comprising a pair of secondary operating surfaces; the pair of rotating gears and the pinion gear being housed within the actuator such that the first operating surfaces of the bevel gears and the secondary operating surfaces of the actuator are cooperatively engaged, wherein relative rotation between the pair of bevel gears imparts a linear motion to the actuator thereby varying the pressure between the pair of interconnected fluid reservoirs to resist the linear motion of the actuator and thereby variably dampen relative motion of the bevel gears to each other.

Abstract: A transfer case for transferring a driving torque of a driving unit of a motor vehicle to a first axle and a second axle of the motor vehicle. The transfer case includes a housing, an input shaft allocated to the driving unit, a first driven shaft allocated to the first axle, and a second driven shaft allocated to the second axle and offset parallel to the input shaft. The transfer case further includes an offset drive for transmitting driving torque from the input shaft to the second driven shaft. The offset drive comprises a gear wheel coaxial to the input shaft or to the driven shaft. The gear wheel is rotatably mounted on a section of the housing.

Abstract: A disconnecting driveline component can include a shaft coupled to one of a pair of output members of a differential. A clutch input can be coupled for rotation with one of a ring gear and the one of the output members. A clutch output can be coupled for rotation with one of a differential case and the shaft. A collar can be axially-slidable between a first position, where the collar couples the clutch input and the clutch output to transmit rotational power therebetween, and a second position where the collar is rotatably decoupled from one of the clutch input and the clutch output. A pilot input can be non-rotatably coupled to the clutch input. A pilot output can be fixed to the clutch output. An electromagnet can draw the pilot input into frictional engagement with the pilot output when the collar is in the second position.

Abstract: The present disclosure relates to a limited-slip driveline apparatus including a first driveline component that is rotatable relative to a second driveline component. The driveline apparatus also includes a clutch configured to resist relative rotation between the first driveline component and the second driveline component at least when the clutch is actuated. The driveline apparatus further includes an actuation arrangement for actuating the clutch. The actuation arrangement includes a hydraulic pump that pumps hydraulic fluid through a hydraulic circuit when relative rotation exists between the first and second driveline components. The hydraulic pressure generated by the hydraulic pump within the hydraulic circuit is used to actuate the clutch. The actuation arrangement also includes a flow regulating valve for regulating a hydraulic fluid flow rate through the hydraulic circuit.

Abstract: A differential gear mechanism can include a differential casing, a piston and an externally mounted plenum assembly. The differential casing can have a differential gear set configured to selectively rotate a first axle shaft and a second axle shaft. The piston can be slidably disposed in the differential casing and configured to actuate a clutch assembly. The externally mounted plenum assembly can include a plenum assembly housing, a hydraulic coupling and a motor mounted on the plenum assembly housing. The plenum assembly housing can define an axle opening configured to receive one of the first and second axle shafts therethrough. The hydraulic coupling can be arranged on the plenum assembly housing at the axle opening. The motor can be configured to pump hydraulic fluid from the externally mounted plenum assembly, through the hydraulic coupling and into the differential casing to act onto the piston.

Abstract: A control system or method for a vehicle references a camera and sensors to determine when an offset of a yaw rate sensor may be updated. The sensors may include a longitudinal accelerometer, a transmission sensor, a vehicle speed sensor, and a steering angle sensor. The offset of the yaw rate sensor may be updated when the vehicle is determined to be stationary by referencing at least a derivative of an acceleration from the longitudinal accelerometer. The offset of the yaw rate sensor may be updated when the vehicle is determined to be moving straight by referencing at least image data captured by the camera. Lane delimiters may be detected in the captured image data and evaluated to determine a level of confidence in the straight movement. When the offset of the yaw rate sensor is to be updated, a ratio of new offset to old offset may be used.

Abstract: A hydraulic coupling for use in a vehicle drivetrain to couple a pair of rotary members and includes a coupling mechanism supported in a casing and that is operable to couple the pair of rotary members together. A piston is responsive to pressurized fluid generated by a pump to move between first and second positions, thereby engaging the coupling mechanism. The pump has an outlet located in a direction away from the piston. An internal passage provides fluid communication between the outlet of the pump and an expandable chamber formed adjacent the piston. A control valve controls the flow of pressurized fluid from the pump between the sump and the expandable chamber.

Abstract: A traction control system and methodology that utilize a phase-out and phase-in of maximum drive torque and/or a regenerative brake torque based on vehicle speed and road slope.

Abstract: A method for controlling an automated clutch, which comprises a hydraulic clutch actuating system having a hydrostatic actuator, the pressure of which is detected. The method includes using the pressure of the hydrostatic actuator to adapt the characteristic curve of the clutch.

Abstract: A method for ascertaining a rotational speed parameter for determining a setpoint torque for driving a drivetrain. The drivetrain comprises a first and at least one second drive assembly for driving a hybrid vehicle. The first drive assembly can be coupled to the drivetrain by means of a clutch. The second drive assembly is mechanically coupled to the drivetrain. When the hybrid vehicle is being driven by means of at least the first drive assembly, the rotational speed parameter corresponds to the value of a shaft rotational speed. When the hybrid vehicle is being driven only by means of the second drive assembly, the rotational speed parameter corresponds to the value of a determined rotational speed.

Abstract: An engine-propelled monowheel vehicle comprises two wheels, close together, that circumscribe the remainder of the vehicle. When the vehicle is moving forward, the closely spaced wheels act as a single wheel, and the vehicle turns by leaning the wheels. A single propulsion system provides a drive torque that is shared by the two wheels. A separate steering torque, provided by a steering motor, is added to one wheel while being subtracted from the other wheel, enabling the wheels to rotate in opposite directions for turning the vehicle at zero forward velocity. The vehicle employs attitude sensors, for sensing roll, pitch, and yaw, and an automatic balancing system. A flywheel in the vehicle spins at a high rate around a spin axis, wherein the spin axis is rotatable with respect to the vehicle's frame. The axis angle and flywheel spin speed are continually adjustable to generate torques for automatic balancing.

Abstract: A vehicle differential assembly is provided that includes a differential adapted to allow differing rotational speed between a pair of outputs. The differential includes a gear assembly connected to the outputs and one or more hydraulically-actuated clutches for selectively and variably coupling the outputs. A hydraulic pump is adapted to generate hydraulic fluid pressure for engagement of the hydraulically-actuated clutches. A variable-engagement clutch is operatively connected to the input and the hydraulic pump such that the input selectively drives the hydraulic pump during engagement of the clutch to provide hydraulic fluid pressure to the hydraulically-actuated clutches. A valve operatively connected to the hydraulic pump and the hydraulically-actuated clutches to selectively and variably provides fluid pressure from the hydraulic pump to the hydraulically-actuated clutches. A method of controlling vehicle stability is also provided.

Abstract: A power transfer assembly for use in a motor vehicle and having a hydraulic coupling operable to transfer drive torque to a driveline in response to slip. The hydraulic coupling includes a transfer clutch, a clutch operator for engaging the transfer clutch, a fluid actuation system including a fluid pump for controlling movement of the clutch operator, and a magnetorheological pump clutch capable of selectively shifting the fluid pump between operative and inoperative states.

Abstract: A transaxle unit comprises a differential assembly having a differential mechanism, a power take-off unit and a torque-coupling device for selectively restricting differential rotation of a differential mechanism. The torque-coupling device includes a friction clutch assembly for selectively frictionally engaging and disengaging a differential case and one of output axle shafts and a hydraulic clutch actuator. The hydraulic clutch actuator includes a hydraulic pump and a variable pressure relief valve assembly fluidly communicating with the hydraulic pump to selectively control a hydraulic pressure generated by the hydraulic pump.

Abstract: A transmission has a lubricant pump which is arranged in the interior of a transmission housing and which includes a rotor rotationally fixedly connected to a transmission shaft in a pump housing, with the pump housing being rotationally fixedly connected to the transmission housing and being sealed with respect to a cylindrical sealing surface of the transmission housing, and with the lubricant pump pumping into a pressure chamber which surrounds the transmission shaft and which is sealed with respect to the transmission shaft. To achieve a good seal and centration of the pump housing, the pump housing is sealed by means of a resilient ring with respect to the cylindrical sealing surface of the transmission housing, with the ring being received by an outer peripheral groove of the pump housing with radial clearance so that the pump housing can adjust itself in the radial direction.

Abstract: A vehicle differential assembly is provided that includes a differential adapted to allow differing rotational speed between a pair of outputs. The differential includes a gear assembly connected to the outputs and one or more hydraulically-actuated clutches for selectively and variably coupling the outputs. A hydraulic pump is adapted to generate hydraulic fluid pressure for engagement of the hydraulically-actuated clutches. A variable-engagement clutch is operatively connected to the input and the hydraulic pump such that the input selectively drives the hydraulic pump during engagement of the clutch to provide hydraulic fluid pressure to the hydraulically-actuated clutches. A valve operatively connected to the hydraulic pump and the hydraulically-actuated clutches to selectively and variably provides fluid pressure from the hydraulic pump to the hydraulically-actuated clutches. A method of controlling vehicle stability is also provided.

Abstract: A differential carrier is disclosed containing sideshaft gears supported in the carrier so as to be coaxially rotatable around a longitudinal axis (A). Differential gears are supported in the carrier on axes of rotation (R) positioned radially relative to the longitudinal axis (A) and have teeth engaging those of the sideshaft gears, and a multi-plate coupling in the carrier to extend coaxially relative to the axis. The carrier includes a flange to which a ring gear can be bolted, and is formed of a dish-shaped part with a base and an integrally formed-on flange and a cover which is axially fixed by an annular securing element. The multi-plate coupling and the cover are positioned in the carrier on the side located opposite the flange and the base.

Abstract: A torque limiting coupling including: (a) an input gear (7) and an output (8) gear interconnected by a torque limiting device; (b) gear chain (9) interconnecting the input and output gears; and (c) a torque limiting device which retains the gear train (7, 8, 9) to prevent relative rotation of the gear train (7, 8, 9) and the input (7) and output gears (8) to provide a 1:1 input output ratio below a predetermined level of input torque and releases the gear train to allow relative rotation between the input (7) and output gears (8) at or above the predetermined level whereby excess torque is dissipated.

Abstract: An axle assembly for a vehicle. The axle assembly includes an input shaft, a first and second output shaft, and a differential assembly. The axle assembly also includes a clutch assembly with an input member coupled to the differential assembly, an output member coupled to one of the first output shaft and the second output shaft, and a clutch member that selectively couples the input and output members. The axle assembly also includes a pump that supplies pressurized fluid to the clutch to control coupling of the input and output members. The axle assembly further includes a motor that drives the pump. The speed of the motor is controllable in order to change a fluid pressure supplied by the pump. The change in fluid pressure from the pump actuates the clutch member to thereby vary the torque between the first output shaft and the second output shaft.

Abstract: A clutch arrangement responsive to a speed difference including an input element and an output element that are rotatable relevant to one another, a friction clutch, and a pump. The friction clutch couples the input element with the output element in dependence on a hydraulic pressure prevails in a pressure space of the clutch arrangement. The pump has a first pump part that is rotationally fixedly connected to the input element and a second pump part that is rotationally fixedly connected to the output element. The pump may be driven by a rotary movement of the input element and the output element relative to one another, with a pressure side of the pump being connected to the pressure space. An orifice having a substantially temperature independent leakage characteristic is arranged at a leakage line that leads from the pressure space to a low pressure space and extends parallel to the pump.

Abstract: A torque-coupling assembly comprises a rotatable torque-coupling case, a friction clutch assembly for selectively engaging the torque-coupling case and an output shaft, a hydraulic pump for generating a hydraulic fluid pressure and a variable pressure-relief valve assembly to selectively control the clutch assembly. The variable pressure-relief valve assembly includes a valve closure member, a valve seat and an electro-magnetic actuator for engaging the valve closure member and generating a variable axial electro-magnetic force acting to the valve closure member so as to selectively vary a release pressure of the pressure-relief valve assembly. The electro-magnetic actuator includes an inverted electro-magnetic coil assembly and an armature disposed inside the electro-magnetic coil assembly and axially movable relative thereto.

Abstract: A coupling device (11) and method of assembly, the device being of the type including a plenum member (17) disposed at one axial end of the coupling housing (13,15), the method comprising configuring the plenum member (17) such that each of the required features (55,57,61,66) is disposed circumferentially between an adjacent pair of fastener holes (18H). Next, the input ring gear (R) is installed about the housing (13,15) of the coupling device (11), from an axial end opposite said plenum member (17), into assembly position adjacent said flange portion (18). Each of a plurality (N) of fasteners (89) is inserted through one of the fastener holes (18H) and into initial threaded engagement with the input ring gear (R). Finally, by means of a fastener driver, all of the plurality (N) of fasteners (89) are driven into full threaded engagement, substantially simultaneously, with the input ring gear (R).

Abstract: A rear axle assembly for a motor vehicle which includes two clutch packs to deliver torque to the right and left hand driven axle shafts of a motor vehicle. The axle assembly clutch packs are efficiently packaged within the axle housing within the inside the diameter of the axle ring gear. A single hydraulic actuator is used to apply hydraulic pressure through a closed circuit to pistons associated with each of the clutch packs to apply compressive force to the clutch packs to energize them. In this manner, the single actuator allows the axle to transfer torque between the ring gear to both the left and right hand axles.

Abstract: An all-wheel drive system for a vehicle having an engine and a drive shaft is arranged between the drive shaft and front and rear propellable shafts. These shafts are interconnected by first and second clutches respectively, and the propellable shafts are coupled to front and rear wheels, for transferring torque from the drive shaft to the front and/or rear wheels. The all-wheel drive system further includes at least first and second actuators that are coupled to at least first and second clutches, where at least the first clutch is engaged by a spring and at least the first actuator is coupled for disengaging the first clutch when the first actuator is operated. The second actuator is coupled for engaging the second clutch when the second actuator is operated.

Abstract: A vehicle differential assembly is provided that includes a differential driven by an input and adapted to allow differing rotational speed between a pair of outputs. The differential includes a gear assembly connected to the outputs and a hydraulically-actuated clutch for selectively and variably coupling the outputs. A hydraulic pump is adapted to generate hydraulic fluid pressure for engagement of the hydraulically-actuated clutch. A variable-engagement clutch is operatively connected to the input and the hydraulic pump such that the input selectively drives the hydraulic pump during engagement of the clutch to provide hydraulic fluid pressure to the hydraulically-actuated clutch. A torque coupling including a variable-engagement clutch is also provided.

Abstract: A hydraulically actuated torque coupling assembly that has an actuator plate mechanism integrated within the pressure relief valve assembly. The actuator plate includes a valve closure member and two alignment pins. The valve closure member is disposed adjacent to a valve seat on the face of the torque coupling assembly. The actuator plate and an associated electro-magnetic solenoid assembly are partially enclosed in a stationary housing that is positioned outside the coupling case. A variable amount of electrical current is applied to the solenoid assembly so that the actuator plate valve closure member engages the associated valve seat. The release pressure of the pressure relief valve assembly is selectively based on the magnitude of an electric current supplied to the solenoid assembly.

Abstract: A torque-coupling assembly comprises a hydraulic fluid reservoir provided for storing a supply of a hydraulic fluid, a hollow coupling casing rotatable by an outside drive torque, a hydraulic pump located within the coupling casing to generate a hydraulic pressure, a supply passage fluidly connecting the hydraulic fluid reservoir to a suction passage of said hydraulic pump and a venting passage. The venting passage is provided for operatively fluidly connecting the supply passage to an ambient atmosphere for selectively enabling or disabling the hydraulic pump.

Abstract: A torque-coupling assembly comprises a rotatable torque-coupling case, a friction clutch assembly for selectively engaging the torque-coupling case and an output shaft, a hydraulic pump for generating a hydraulic fluid pressure, a fluid control passage through which a hydraulic fluid is discharged from the torque-coupling case, and a variable pressure-control valve assembly to selectively control the clutch assembly. The variable pressure-control valve assembly includes a spool valve disposed in the fluid control passage and an electro-magnetic actuator. The electro-magnetic actuator is provided for producing a variable axial electro-magnetic force acting to the spool valve so as to selectively adjust a position of the spool valve in the fluid control passage in order to selectively control a flow rate of the hydraulic fluid in the fluid control passage.

Abstract: A hydraulic fluid plenum plate assembly in a torque-coupling assembly, non-rotatably mounted to a rotatable coupling case thereof so as to form a plenum chamber between the plenum plate assembly and the coupling case. The coupling case has an inlet port fluidly connecting the plenum chamber with a hydraulic pump disposed within the coupling case. The plenum plate assembly comprises a pickup tube for supplying a hydraulic fluid from a fluid reservoir to the plenum chamber. The pickup tube has inlet and outlet ends. The inlet end has an inlet opening submerged in the hydraulic fluid in the fluid reservoir. The outlet end has an outlet opening fluidly connecting the pickup tube with the plenum chamber. The outlet opening is disposed above the inlet port in the coupling case at any angular position of the coupling case relative to the plenum plate assembly.

Abstract: A coupling device (11;111) including a rotatable housing (13,15;113) defining a clutch cavity and a clutch assembly (29;129) disposed therein. The housing defines an apply chamber (37;137) and a clutch apply member (39) disposed therein to bias the clutch assembly into engagement. A source of pressurized fluid for the clutch apply member comprises a pumping element (59,61;159,161) operable to pump pressurized fluid in response to rotation of a rotor (61;161). There is a stationary plenum assembly (51;153) defining a pumping chamber, and the pumping element is operably disposed within the pumping chamber, and a drive means (63;163) is operable to transmit rotational movement of the rotatable housing (13,15;113) to said rotor (61;161) of the pumping element, such that clutch engagement is not dependent upon coupling input-to-output speed differential.

Abstract: Pump pressure output can be controlled as temperature changes by a temperature compensation element. The present invention provides a shear channel constructed out of two or more materials enabling a pump to have a pressure profile as a function of temperature for a viscous fluid. The channel height varies as a function of temperature when the channel walls and temperature compensation element are constructed from materials having different coefficients of thermal expansion. By selecting a combination of materials, the channel height can increase, decrease, or remain constant as the temperature is changed. Ignoring the effects of viscosity, channel length, and relative speed the effect of channel height on pump output pressure is assessed: by increasing channel height as temperature increases, the pressure will decrease; by keeping the channel height constant as temperature increases, the pressure will remain constant; and by decreasing channel height as temperature increases, the pressure will increase.

Abstract: A coupling device (11) and method of assembly, the device being of the type including a plenum member (17) disposed at one axial end of the coupling housing (13,15), the method comprising configuring the plenum member (17) such that each of the required features (55,57,61,66) is disposed circumferentially between an adjacent pair of fastener holes (18H). Next, the input ring gear (R) is installed about the housing (13,15) of the coupling device (11), from an axial end opposite said plenum member (17), into assembly position adjacent said flange portion (18). Each of a plurality (N) of fasteners (89) is inserted through one of the fastener holes (18H) and into initial threaded engagement with the input ring gear (R). Finally, by means of a fastener driver, all of the plurality (N) of fasteners (89) are driven into full threaded engagement, substantially simultaneously, with the input ring gear (R).

Abstract: A differential gear mechanism (11) and improved axle shaft (53) retention arrangement for the axle shaft. The mechanism includes a side gear (27) defining first internal splines, a coupling (35) defining second internal splines (35S), and a rotor (49) of a gerotor pump defining third internal splines (49S). The axle shaft includes external splines (55), an annular groove (57), and a collapsible and expandable retention ring (59) within the groove. The assembly operator aligns the external splines with the third internal splines (49S), then with the second internal splines (35S), and finally, with the first internal splines (27S), before exerting force (“F” in FIG. 3) on the axle shaft to collapse the retention ring by passing it through the third internal splines (49S) until the ring can expand (FIG. 4). The axle shaft is retained as the retention ring engages an inboard end (69) of the third internal splines.

Abstract: A starter/generator system for a gas turbine engine used in aeronautical applications that couples a single dynamoelectric machine to the gas turbine engine through a torque converter in a starting mode, and then disengages the torque converter and engages the engine to the dynamoelectric machine through an adjustable speed transmission in a generating mode after the engine reaches self-sustaining speed, wherein the speed of the adjustable speed transmission is set to match the frequency of AC generated by the dynamoelectric machine with on-board electrical equipment requirements to suit flight conditions.

Abstract: A coupling device (11) of the type including a clutch assembly (29) actuation of which is responsive to fluid pressure in a clutch piston apply chamber (43), and a series of fluid passages (53,55,57,59) communicating the chamber to a control valve assembly (69). A housing (15) defines a hub portion (61) surrounded by a plenum member (17) carrying two high pressure seals (63;163). The housing is formed such that the outer surface (60) of the hub portion is free of graphite porosity, to improve the life of the seals. Preferably, each of the seals (63;163) has a height/width ratio selected to provide the desired radially inward sealing force, but wherein the seals are still able to be assembled within the respective seal cavities (73,75;173,175).

Abstract: A hydraulic control apparatus for a vehicle including an electric oil pump, a pump control portion which controls the electric oil pump, a hydraulic circuit portion which supplies a hydraulic pressure from the electric oil pump to an actuator of a transaxle of the vehicle, a hydraulic circuit control portion which outputs a control signal to the hydraulic circuit portion, and an oil pump rotation control portion which is provided in the pump control portion and which controls a rotational state of the electric oil pump according to a change in a control status of the hydraulic circuit control portion.

Abstract: A drive axle assembly for use in an all-wheel drive vehicle having a first hydraulic coupling operable to automatically transfer drive torque to a secondary driveline in response to slip of the primary driveline and a second hydraulic coupling operable to bias torque and limit slip between the wheels of the secondary driveline. The first hydraulic coupling is electronically-controlled.

Abstract: An apparatus and method for controlling a limited slip differential uses a solenoid operated valve having an armature attached a differential case of the differential for rotation therewith, and an actuating coil operatively attached to a non-rotating differential housing, for modulating pressure in a hydraulically actuated limited slip device of the limited slip differential. The actuating coil is mounted on a non-rotating plenum, sealed to the differential case with low pressure dynamic seals.

Abstract: A pressure control valve assembly is disposed in the hydraulic flow path of a differential assembly and is connected to a passageway leading to a limited slip device within the differential case to establish fluid communication there between. The invention includes a machined or formed blind hole, a groove which partially intersects the blind hole, a ball member seated in the blind hole, and a spring resiliently acting on the ball to apply a force biasing the ball into the blind hole. At the intersection of the blind hole and groove, an area, which is not sealed by the ball, is formed that provides a controlled leakage path for the hydraulic fluid. As the hydraulic fluid flow increases, the hydraulic pressure of the fluid on the pressure side increases which increases the force on the ball acting against the spring. As the pressure increases further, the resultant forces on the ball deflect the spring to increase the bleed area and increase the fluid bled proportionally to the fluid pressure.

Abstract: A differential assembly for a motor vehicle comprises a differential case rotatably supported in an axle housing, opposite output shafts drivingly connected to the differential case, a friction clutch assembly for selectively engaging and disengaging the differential case and the output shaft, and a hydraulic clutch actuator for selectively frictionally loading the clutch assembly. The hydraulic clutch actuator includes a variable pressure relief valve controlled by a solenoid actuator for selectively engaging the friction clutch assembly. In order to provide the solenoid actuator with an electrical power and/or control signals in a contactless manner, the differential assembly is further provided with a transformer assembly including a primary transformer unit non-rotatably mounted to the axle housing and connected to a source of electrical energy, and a rotatable secondary transformer unit secured to an outer peripheral surface of the differential case.

Abstract: A hydraulic coupling assembly is provided for an auxiliary drive axle of an all wheel drive motor vehicle. The hydraulic coupling assembly comprises a rotatable casing, first and second output shafts axially outwardly extending from said casing, at least one hydraulically operated, selectively engageable friction clutch assembly for operatively coupling the casing to at least one of the output shafts, and at least one hydraulic clutch actuator. The hydraulic actuator includes a hydraulic pump located within the casing and adapted to generate a hydraulic pressure to frictionally load the friction clutch assembly, and a variable pressure relief valve assembly fluidly communicating with the hydraulic pump to selectively control the hydraulic pressure generated by the pump. The variable pressure relief valve assembly includes an electro-magnetic actuator selectively for varying a release pressure of the pressure relief valve assembly based on a magnitude of an electric current applied thereto.

Abstract: A differential assembly for a motor vehicle comprises a differential case rotatably supported in an axle housing, opposite output shafts drivingly connected to the differential case, a friction clutch pack for controlling the differential action, and a hydraulic clutch actuator for selectively fictionally loading the clutch pack. The hydraulic clutch actuator includes a variable pressure relief valve assembly to selectively control the friction clutch pack. The variable pressure relief valve assembly includes a valve closure member, a valve seat complementary to the valve closure member, and an electro-magnetic actuator for engaging the valve closure member and urging thereof against the valve seat with an axial force determined by a magnitude of an electric current supplied to the electro-magnetic actuator so as to selectively vary a release pressure of the pressure relief valve assembly based on the magnitude of the electric current.

Abstract: A hydraulically actuated friction coupling comprises a hollow case, an output shaft drivingly connected to the case, a friction clutch pack for selectively engaging and disengaging the case and the output shaft, and a hydraulic clutch actuator. The hydraulic actuator includes a hydraulic pump for generating a hydraulic pressure to frictionally load the clutch pack, and a piston assembly disposed within the case between the pump and the clutch pack. The piston assembly includes an annular pressure plate adjacent to the pump, an annular thrust plate axially spaced from the pressure plate and adjacent to the clutch pack, and a pair of concentric radially spaced resilient annular seal members bonded to the pressure and thrust plates so as to define an annular cavity within the piston assembly. The annular cavity in the piston assembly is in fluid communication with an output port of the hydraulic pump.

Abstract: A differential device for transferring torque and rotation from an input shaft to a first output shaft and a second output shaft of a vehicle is provided. The differential device includes a carrier coupled to an input shaft, a first pump/motor coupled to the carrier and to the first output shaft, and a second pump/motor coupled to the carrier and to the second output shaft. The first pump/motor preferably functions to pump a hydraulic fluid upon a rotation of the first output shaft at a different speed than the carrier, and to rotate the first output shaft at a different speed than the carrier upon a sufficient pressurization of the hydraulic fluid. Similarly, the second pump/motor preferably functions to pump a hydraulic fluid upon a rotation of the second output shaft at a different speed than the carrier, and to rotate the second output shaft at a different speed than the carrier upon a sufficient pressurization of the hydraulic fluid.