Abstract: An over-running clutch includes an outer race and an inner race defining a gap therebetween. A plurality of rolling elements are positioned between the inner and outer races. A retainer interconnects the rolling elements. A first biasing element biases the retainer to hold the rolling elements such that the inner and outer races are free to rotate relative to one another. An actuator selectively forces the rolling elements to a position where the rolling elements engage and wedge between the inner and outer races, thereby locking the clutch. A sensor is adapted to detect the engagement of the clutch and to send a corresponding signal.

Abstract: A drive power transmission device is disclosed having a drive mechanism for transmitting a drive power between first and second rotary members rotatable relative to each other, by the operation of an electromagnetic type clutch mechanism which brings a friction clutch into connection. A magnetic path generated around an electromagnet of the electromagnetic type clutch mechanism includes a clutch magnetic path in which a magnetic flux passes to reciprocate plural times across th friction clutch, and diamond-like carbon surface treatment is given on a part or all of the friction contact surfaces of the friction clutch to form a hard amorphous carbon film thereon. Thus, the transmission device can be constructed using a smaller number of the outer and inner plates for the electromagnetic type clutch mechanism, so that it can take a small construction with a longer durability life.

Abstract: An electromagnetic clutch 1 is disclosed having a magnetic flux loop 31 formed, in magnetic flux loop forming members 5, 7, 9, 11, 13 involving an electromagnet 5 and an armature 13, by the electromagnet 5 to allow the armature 13 to be operatively shifted to couple and uncouple a clutch 11, and a proximate member, close proximate to the members 5, 7, 9, 11, 13, includes magnetic flux leakage minimizing sections 15, 17, 19, 21, 23, 25 that minimize magnetic fluxes leaked from the armature 13 to the proximate member.

Abstract: A torque transfer mechanism having a multi-plate friction clutch connecting a pair of rotary members and a electrohydraulic clutch actuator for controlling engagement of the friction clutch. The clutch actuator includes a hydraulic pump, a hydraulically actuated rotary operator, and a thrust mechanism. The hydraulic pump draws low pressure fluid from a sump and selectively delivers high pressure fluid to a series of actuation chambers and return chambers defined between coaxially aligned first and second components of the rotary operator. The magnitude of the fluid pressure delivered to the actuation chamber controls angular movement of the second component relative to the first component for energizing the thrust mechanism. The thrust mechanism applies a clutch engagement force on the friction clutch, thereby transferring drive torque from the first rotary member to the second rotary member. An electrohydraulic control system regulates the fluid pressure delivered to the actuation and return chambers.

Abstract: A torque transfer mechanism having a transfer clutch connecting a pair of rotary members and a electrohydraulic clutch actuator for controlling engagement of the transfer clutch. The clutch actuator includes a hydraulic pump and a hydraulically-actuated rotary operator. The hydraulic pump draws low pressure fluid from a sump and delivers high pressure fluid to a series of actuation chambers defined between coaxially aligned first and second components of the rotary operator. The magnitude of the fluid pressure delivered to the actuation chamber controls angular movement of the second component relative to the first component for energizing a pilot ball ramp unit. The pilot ball ramp mechanism applies a clutch actuation force on a pilot friction clutch which energized a main ball ramp unit for applying a clutch engagement force to a main friction clutch. A hydraulic control system adaptively regulates the fluid pressure delivered to the actuation chamber.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes an actuator having a first cam fixed for rotation with the first rotary member and a second cam having a rotor which is rotatably disposed within a chamber filled with magnetorheological fluid. An electromagnetic coil is disposed in proximity to the chamber and is selectively energized for varying the viscosity of the magnetorheological fluid so as to induce axial movement of the first cam for engaging the multi-plate clutch assembly.

Abstract: A torque transfer mechanism having a transfer clutch connecting a pair of rotary members and a electrohydraulic clutch actuator for controlling engagement of the transfer clutch. The clutch actuator includes a hydraulic pump and a hydraulically-actuated rotary operator. The hydraulic pump draws low pressure fluid from a sump and delivers high pressure fluid to a series of actuation chambers defined between coaxially aligned first and second components of the rotary operator. The magnitude of the fluid pressure delivered to the actuation chamber controls angular movement of the second component relative to the first component for energizing a pilot ball ramp unit. The pilot ball ramp mechanism applies a clutch actuation force on a pilot friction clutch which energized a main ball ramp unit for applying a clutch engagement force to a main friction clutch. A hydraulic control system adaptively regulates the fluid pressure delivered to the actuation chamber.

Abstract: A torque transfer mechanism having a multi-plate friction clutch connecting a pair of rotary members and a electrohydraulic clutch actuator for controlling engagement of the friction clutch. The clutch actuator includes a hydraulic pump, a hydraulically-actuated rotary operator, and a thrust mechanism. The hydraulic pump draws low pressure fluid from a sump and selectively delivers high pressure fluid to a series of actuation chambers and return chambers defined between coaxially aligned first and second components of the rotary operator. The magnitude of the fluid pressure delivered to the actuation chamber controls angular movement of the second component relative to the first component for energizing the thrust mechanism. The thrust mechanism applies a clutch engagement force on the friction clutch, thereby transferring drive torque from the first rotary member to the second rotary member. An electrohydraulic control system regulates the fluid pressure delivered to the actuation and return chambers.

Abstract: A drive system control method and a drive power transmission control system for a four-wheel drive vehicle are provided for enabling the vehicle to operate selectively in an ordinary mode and an anti-vibration mode. In the ordinary mode, the connection force of a coupling device which is provided between front and rear wheel torque transmission axles is kept relatively high, and the front and rear wheel torque transmission axles are brought to connect prime drive wheels with secondary drive wheels, so that four-wheel drive traveling of the vehicle can be realized. The operation mode of the vehicle is switched from the ordinary mode to the anti-vibration mode where the secondary drive wheels slip when the vehicle begins to start in the ordinary mode. In the anti-vibration mode, the connection force of the coupling device is relatively weakened to substantially separate the front and rear wheel torque transmission axles from each other.

Abstract: An electromagnetic clutch for motor vehicle drive line applications includes a friction clutch pack, a ball ramp actuator and an electromagnetic coil. The ball ramp actuator includes a pair of circular members having opposed pairs of arcuate recesses receiving load transferring members and a torsion spring which provides a restoring force to return the circular members to their center, disengaged positions. Improved clutch control, particularly during disengagment, is achieved by this ball ramp actuator configuration.

Abstract: A clutch having a multiple pole electromagnetic actuator is useful in motor vehicle powertrain components such as transaxles, transfer cases, transmissions, differentials and the like. The electromagnetic actuator includes a stationary coil, a rotating, multiple pole stator and a rotating, multiple pole armature which is linked to the stator. Both the stator and the armature include multiple coils which are electrically connected in pairs. A cam or ball ramp assembly is disposed between the armature and a friction clutch pack. Energization of the stationary coil induces current in the coils of the stator and the respective coils of the armature. The magnetic flux and force generated rotates the armature relative to the stator, thereby actuating the cam or ball ramp assembly, which in turn, compresses the friction clutch pack.

Abstract: A friction clutch has a plurality of iron inner clutch plates and a plurality of iron outer clutch plates. Both the clutch plates have sliding surfaces which are friction-engaged each other. A thin carbon film in a diamond form, which functions as a solid lubricant, is formed on each of the sliding surfaces of the outer clutch plates by a known method such as the Chemical Vapor Deposition method. A known nitride treatment or quenching and tempering treatment is applied to the sliding surfaces of the inner clutch plates. A coupling device has a pilot clutch mechanism with the friction clutch and an electromagnetic actuator. As a result, the friction clutch is resistant to wear and the coupling device is excellent in durability.

Abstract: An electromagnetic clutch assembly having a solenoid activated ball ramp operator provides reduced power consumption and improved control. The electromagnetic clutch assembly includes a primary or pilot friction clutch pack and a secondary or main friction clutch pack. An annular solenoid coil cooperates with an annular operator or plunger. When the coil is energized, the annular plunger translates and compresses the primary or pilot friction clutch pack. Activation of the pilot clutch pack retards motion of one of the members of the ball ramp operator which, in turn, compresses a secondary or main friction clutch pack disposed across the input and output members.

Abstract: In a power transfer device composed of a bottomed cylindrical housing 20a rotatably mounted on an inner shaft 20b and a main friction clutch 20c and a pilot friction clutch 30a coaxially assembled within a cylindrical space between the housing 20a and inner shaft 20b through a cam mechanism 30b, the thickness of a shim plate 39b for adjustment of a clearance between an inner clutch plate or outer clutch plate located at one side of an electromagnetic clutch 30a used as the pilot friction clutch and an inner end surface of an end wall block 21b threaded into an opening end portion of the housing 20a is determined on a basis of a clearance L1 between one side surface of a thrust bearing 39a assembled with an input cam member 35 of the cam mechanism 30b and an inner clutch plate or outer clutch plate located at one side of the electromagnetic clutch 30a.

Abstract: In a shift mechanism for an outboard motor mounted on a stern of a boat and having an internal combustion engine and a propeller connected by a propeller shaft to the engine to propel the boat, a vertical shaft connected to the engine and transmitting an output of the engine to the propeller shaft is divided into two shaft halves and an electromagnetic clutch is provided to connect/disconnect the shaft halves. An electronic controller is provided to operate the electromagnetic clutch to disconnect the vertical shaft halves until one of the forward and reverse gears corresponding to the instruction to shift has been engaged with the propeller shaft, and then operate it to connect the shaft halves after the one of the forward gear and the reverse gear has been engaged with the propeller shaft.

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members (2, 4) has a number of alternate clutch discs (5, 6), connected to the two shaft members and engageable to counteract differential rotational speed between the shaft members. The rotational movement may be braked by braking means (26-28), whose rotational velocity is proportional to the rotational speed differential. Means for transmitting the rotational speed differential to the braking means comprises a roller arrangement (20-25).

Abstract: To provide a vehicular two-wheel drive and four-wheel drive switching system the configuration of which is simple and which can be built with minor changes to the existing configuration. The switching system hardly generates any noise and can be individually lubricated in a state separated from the other actuating parts. A vehicular two-wheel drive and four-wheel drive switching system according to the present invention is provided with an outer ring connected to a driving shaft and an inner ring connected to a driven shaft. A plurality of engaging/disengaging members are provided for connecting or disconnecting the shafts by being connected or disconnected to/from the respective opposite surfaces. A switching mechanism is provided for selectively positioning the drive shaft and the driven shaft in a position in which they are connected and in a position in which they are disconnected.

Abstract: A driving force transmitting apparatus includes a clutch mechanism for bringing a pilot clutch to a frictionally engaged condition, and a cam mechanism for bringing a main clutch for transmitting driving force to a frictionally engaged condition during operation of the clutch mechanism. The cam mechanism includes a pilot cam member, a main cam member, a stopper member, and a biasing means for biasing the stopper member in a rotational direction for respectively engaging the pilot cam member and the main cam member to the stopper member. A position of the pilot cam member, the main cam member, and the stopper member is determined depending on a relationship between a biasing force to the stopper member by the biasing means and a torque to the pilot cam member.

Abstract: A tuning method for the exciting current-transmission torque characteristic of a power transmission apparatus is provided. A yoke (36), which supports an electromagnet (33), is accommodated in a groove (53) and is apart from the groove by a first distance (L2) and a second distance (L4). The exciting current-transmission torque characteristic is tuned by varying the first distance while keeping the second distance fixed. When the first distance is varied, the variation of the magnetoresistance of a magnetic path is relatively small. Therefore, the exciting current-transmission torque characteristic is more accurately tuned.

Abstract: An axial setting device comprising two plates (24, 29) which are relatively rotatable and coaxially supported relative to one another and between which balls are guided in pairs of ball grooves (34, 39) in the plates (24, 29), with the depth of said pairs of ball grooves (34, 39) being circumferentially variable; of the plates (24, 29), one is axially supported and one is axially displaceable against the elastic returning forces of spring means; at least one of the plates (24, 29) is drivable via a driveline by a driving motor (11). Within the driveline, between the driving motor (11) and the drivable plates (24, 29), there is inserted a switching coupling (83).

Abstract: A power transfer system is provided and equipped with a torque transfer coupling which includes a stage 2 clutch and a clutch actuator. The clutch actuator includes stage 1 and stage 2 ball ramp actuators as well as a stage 1 clutch operably positioned between the ball ramp actuators to operatively engage the stage 2 clutch and vary the frictional engagement thereof.

Abstract: The differential includes a differential casing configured to be rotatably driven by a motor under a driving force. The differential includes a differential mechanism which includes a pair of first and second side-gears for distributing a torque of the differential casing to first and second output shafts. The differential includes a frictional clutch for interconnecting the first and second output shafts. The frictional clutch includes first and second power-transmitting members connected to first and second output shafts respectively and first and second clutch plates. The first and second clutch plates are connected to the first and second power-transmitting members respectively. The differential includes an actuator for operating the frictional clutch. One output shaft of the first and second output shafts is axially displacable by the actuator under an engagement force to engage the frictional clutch.

Abstract: An electromagnetic clutch assembly having a ball ramp operator provides enhanced torque throughput capability. The electromagnetic clutch assembly includes a primary or pilot friction clutch pack and a secondary or main friction clutch pack. A ball ramp operator which is actuated by the primary or pilot friction clutch pack includes a plastic washer or annulus adjacent one of the operator members. The plastic washer provides feedback which enhances the operation of the primary friction clutch pack, augments the compressive force applied to the secondary or main clutch pack and thus increases the torque throughput capability of the electromagnetic clutch assembly.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes an actuator having a first segment fixed for rotation with the first rotary member and a second segment having a screw thread formed thereon which is rotatably and slidably disposed within a chamber filled with magnetorheological fluid. An electromagnetic coil is disposed in proximity to the chamber and is selectively energized for varying the viscosity of the magnetorheological fluid so as to induce axial movement of the actuator for engaging the multi-plate clutch assembly.

Abstract: A device for transmitting torque between two rotatable, coaxial shaft members has a number of alternate clutch discs, connected to the two shaft members and engageable to counteract differential rotational speed between the shaft members. The rotational movement may be braked by braking means, whose rotational velocity is proportional to the rotational speed differential. Means for transmitting the rotational speed differential to the braking means comprises a number of balls arranged between on one hand a rotatable, first thrust ring and a second thrust ring attached to one of the shaft members and on the other hand an outer ring fixed to a housing of the device and a gear ring engaging a rotatable brake shaft of the braking means.

Abstract: The magnetic attraction force of an electromagnetic coil in an electromagnetic clutch is increased in a limited installation space, thereby improving reliability of operation. The dimensions of a field core housing the electromagnetic coil and a rotor are optimized to increase the magnetic attraction force. The thicknesses of cylindrical portions on the inner-diameter side of the field core and the rotor have larger thicknesses than those of cylindrical portions on its outer-diameter side so that the sectional areas of both cylindrical portions will be equal to each other. Also, a rotation transmission device provided with an electromagnetic clutch is proposed which can avoid deterioration of its sealing property and damage to its bearing and avoid cost increase.

Abstract: In a power transfer device composed of a bottomed cylindrical housing 20a rotatably mounted on an inner shaft 20b and a main friction clutch 20c and a pilot friction clutch 30a coaxially assembled within a cylindrical space between the housing 20a and inner shaft 20b through a cam mechanism 30b, the thickness of a shim plate 39b for adjustment of a clearance between an inner clutch plate or outer clutch plate located at one side of an electromagnetic clutch 30a used as the pilot friction clutch and an inner end surface of an end wall block 21b threaded into an opening end portion of the housing 20a is determined on a basis of a clearance L1 between one side surface of a thrust bearing 39a assembled with an input cam member 35 of the cam mechanism 30b and an inner clutch plate or outer clutch plate located at one side of the electromagnetic clutch 30a.

Abstract: A transfer mechanism is provided for controlling a magnitude of clutch engagement force exerted on a multi-plate clutch assembly operably disposed between input and output members. The transfer clutch includes an actuator fixed for rotation with the input member, a piston slidably disposed within a piston chamber of the actuator and selectively engaging the multi-plate clutch assembly, a pump in fluid communication with the piston chamber, and operably engaged with the input member and the output member. A rotational speed differential between the input member and the output member induces pumping action for pumping a magnetorheological fluid through the piston chamber. An electromagnetic coil is operably disposed between the piston chamber and the pump. The electromagnetic coil is selectively energized for manipulating a viscosity of the magnetorheological fluid to induce a back pressure within the piston chamber, thereby inducing axial movement of the piston for engaging the clutch pack.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a clutch actuator assembly for generating and applying a clutch engagement force on the clutch assembly. The clutch actuator assembly includes an electric motor/brake unit and a torque/force conversion mechanism. The motor/brake unit can be operated in either of a motor mode or a brake mode to cause bi-directional linear movement of an output member of the torque/force conversion mechanism. The thrust force generated by the torque/force conversion mechanism is applied to the clutch assembly. The dual mode feature of the electric motor/brake unit significantly reduces the power requirements.

Abstract: An electromagnetic clutch for motor vehicle drive line applications includes a friction clutch pack, a ball ramp actuator and an electromagnetic coil. The ball ramp actuator includes a pair of circular members having opposed pairs of arcuate recesses receiving load transferring members and a torsion spring which provides a restoring force to return the circular members to their center, disengaged positions. Improved clutch control, particularly during disengagment, is achieved by this ball ramp actuator configuration.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a clutch actuator for generating and applying a clutch engagement force on the clutch assembly. The clutch actuator includes a wedge fork having a gear rack segment and a tapered tang segment and a reaction block defining a tapered edge in sliding engagement with the tapered tang segment. An electric motor drives a pinion that is meshed with the gear rack to cause bi-directional linear movement of the wedge fork which causes corresponding sliding movement of the reaction block relative to the clutch assembly.

Abstract: Differential apparatus which includes input and output members rotatable relative to each other, a clutch mechanism for interconnecting them, an actuator and a cam mechanism. The clutch mechanism includes first and second clutch members rotating with the input and output members, respectively. The actuator limits rotation of the second clutch member relative to the input member to angularly displace the second clutch member relative to the output member. The cam mechanism is provided between the second clutch member and the output member, and includes first and second cam faces rotating with the second clutch member and the output member, respectively. When the actuator operates, these cam faces cooperate to axially displace the second clutch member away from the output member, whereby the second clutch member is axially displaced to engage with the first clutch member.

Abstract: A torque cam mechanism comprises first and second cam members disposed relatively rotatably around a common axis and cam balls adapted to fit in first and second cam grooves formed, respectively, in confronting surfaces of the first and second cam members. The depth of the first cam grooves is made larger than the radius of the cam balls, whereas the depth of the second cam grooves is made smaller than the radius of the cam balls, whereby even though a centrifugal force is applied to the cam balls which rotate together with the first and second cam members, the generation of thrust forces for separating the confronting surfaces of the first and second cam members can be suppressed by receiving the centrifugal force so applied to the cam balls by the first cam grooves which are deeper.

Abstract: A transfer mechanism is provided for controlling a magnitude of clutch engagement force exerted on a multi-plate clutch assembly operably disposed between input and output members. The transfer clutch includes an actuator fixed for rotation with the input member, a piston slidably disposed within a piston chamber of the actuator and selectively engaging the multi-plate clutch assembly, a pump in fluid communication with the piston chamber, and operably engaged with the input member and the output member. A rotational speed differential between the input member and the output member induces pumping action for pumping a magnetorheological fluid through the piston chamber. An electromagnetic coil is operably disposed between the piston chamber and the pump. The electromagnetic coil is selectively energized for manipulating a viscosity of the magnetorheological fluid to induce a back pressure within the piston chamber, thereby inducing axial movement of the piston for engaging the clutch pack.

Abstract: The present invention is directed to a power transfer system for a four-wheel drive vehicle equipped with a torque transfer coupling which includes a clutch pack and a ball-screw actuator. The ball-screw actuator functions to axially translates an apply plate to operatively engage the clutch pack and vary the frictional engagement. This arrangement yields numerous operational advantages over the prior art including, but not limited to, establishing a direct drive between the motor output shaft and the apply plate, concentric mounting of the actuator elements with the motor output shaft, and a simplified mechanical arrangement that reduces the number of frictional elements increasing operational efficiency and decreasing motor.

Abstract: The present invention is directed to a power transfer system for a four-wheel drive vehicle equipped with a torque transfer coupling which includes a clutch pack and a ball-screw actuator. The ball-screw actuator functions to axially translates an apply plate to operatively engage the clutch pack and vary the frictional engagement. This arrangement yields numerous operational advantages over the prior art including, but not limited to, establishing a direct drive between the motor output shaft and the apply plate, concentric mounting of the actuator elements with the motor output shaft, and a simplified mechanical arrangement that reduces the number of frictional elements increasing operational efficiency and decreasing motor requirements.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes an actuator having a first segment fixed for rotation with the first rotary member and a second segment having a screw thread formed thereon which is rotatably and slidably disposed within a chamber filled with magnetorheological fluid. An electromagnetic coil is disposed in proximity to the chamber and is selectively energized for varying the viscosity of the magnetorheological fluid so as to induce axial movement of the actuator for engaging the multi-plate clutch assembly.

Abstract: The magnetic attraction force of an electromagnetic coil in an electromagnetic clutch is increased in a limited installation space, thereby improving reliability of operation. The dimensions of a field core housing the electromagnetic coil and a rotor are optimized to increase the magnetic attraction force. The thicknesses of cylindrical portions on the inner-diameter side of the field core and the rotor have larger thicknesses than those of cylindrical portions on its outer-diameter side so that the sectional areas of both cylindrical portions will be equal to each other. Also, a rotation transmission device provided with an electromagnetic clutch is proposed which can avoid deterioration of its sealing property and damage to its bearing and avoid cost increase.

Abstract: A rotation transmission device is provided which is used to selectively transmit power. The aim is to stabilize the frictional torque when the rotor of an electromagnet absorbs an armature. A retainer is mounted between an inner member and an outer member, and is formed with a plurality of pockets, and engaging elements are mounted in the pockets. An armature is mounted so as to be nonrotatable but axially movable relative to the retainer, and a rotor is mounted to the inner member or the outer member so as to axially oppose the armature. An electromagnet attracts the armature to the rotor, thereby changing the phase of the retainer to bring the engaging elements into engagement with the outer periphery of the inner member and the inner periphery of the outer member, and thereby transmitting a turning torque between the inner member and the outer member. When the armature is attracted to the rotor, the large-diameter portion of the armature is attracted to the rotor.

Abstract: A torque transfer mechanism is provided for controlling the magnitude of a clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between a first rotary and a second rotary member. The torque transfer mechanism includes a clutch actuator for generating and applying a clutch engagement force on the clutch assembly. The clutch actuator includes a wedge fork having a gear rack segment and a tapered tang segment and a reaction block defining a tapered edge in sliding engagement with the tapered tang segment. An electric motor drives a pinion that is meshed with the gear rack to cause bi-directional linear movement of the wedge fork which causes corresponding sliding movement of the reaction block relative to the clutch assembly.

Abstract: A drive power transmission device is disclosed having a drive mechanism for transmitting a drive power between first and second rotary members rotatable relatlve to each other, by the operation of an electromagnetic type dutch mechanism which brings a friction clutch into connection. A magnetic path generated around an electromagnet of the electromagnetic type clutch mechanism includes a clutch magnetic path in which a magnetic flux passes to reciprocate plural times across th friction clutch, and diamond-like carbon surface treatment is given on a part or all of the friction contact surfaces of the friction clutch to form a hard amorphous carbon film thereon. Thus, the transmission device can be constructed using a smaller number of the outer and inner plates for the electromagnetic type clutch mechanism, so that it can take a small construction with a longer durability life.

Abstract: A vehicle driveline assembly for an automotive vehicle includes a differential assembly adapted to transfer torque proportionally between first and second axle half-shafts. An over-running clutch is adapted to selectively lock the differential assembly thereby effectively rotationally locking the axle half shafts to one another. The differential has three modes of operation; an open mode, wherein the differential is kept un-locked; a locked mode, wherein the differential is kept locked; and an automatic mode, wherein the differential is locked or un-locked based upon predetermined operating parameters. A selector switch allows an operator to selectively place the differential in one of the three modes. An electronic control unit receives inputs from the vehicle, compares the inputs to pre-determined operating parameters, and selectively engages or disengages the over-running clutch when the differential is in the automatic mode.

Abstract: A wet-type friction clutch plate which keeps lubricant on a frictional slide face, stabilizes frictional torque transmission and suppresses shuddering noise. The wet-type friction clutch plate has the frictional slide face on which a grid of grooves is formed. The frictional slide face frictionally engages with an opposite clutch plate. At least one of the sectional shape and plan shape of each of the grooves is configured to provide the frictional slide face with a &mgr;-v characteristic such that &mgr; increases with an increase in v to prevent self-excited vibration during frictional engagement of the wet-type friction clutch plate with the opposite clutch plate, wherein &mgr; is a coefficient of friction on the frictional slide face and v is a relative rotational speed of the wet-type friction clutch plate relative to the opposite clutch plate.

Abstract: An electromagnetic clutch 1 is disclosed having a magnetic flux loop 31 formed, in magnetic flux loop forming members 5, 7, 9, 11, 13 involving an electromagnet 5 and an armature 13, by the electromagnet 5 to allow the armature 13 to be operatively shifted to couple and uncouple a clutch 11, and a proximate member, close proximate to the members 5, 7, 9, 11, 13, includes magnetic flux leakage minimizing sections 15, 17, 19, 21, 23, 25 that minimize magnetic fluxes leaked from the armature 13 to the proximate member.

Abstract: A clutch pack actuation system for compressing the annular clutch pack of a limited slip differential includes a pump which can provide a supply of pressurized fluid, an annular member provided between the pump and the annular clutch pack, and an annular piston which is slidable within the annular member. Together with the annular member, the annular piston defines a clutch pressure chamber adapted to receive the supply of pressurized fluid. A fluid return line, by which the pressurized fluid is discharged from the clutch pressure chamber, is provided, and a valve, through which the pressurized fluid is returned to a fluid reservoir, is disposed in the fluid return line. The valve includes an element which is electromagnetically actuated so as to produce a desired pressure in the clutch pressure chamber.

Abstract: An over-running clutch assembly comprises an outer race having a cylindrical inner surface and an inner race having a cammed outer surface coaxial with the cylindrical inner surface and defining a gap therebetween and a roller clutch disposed within the gap; a biasing element biases the roller clutch to a disengaged position; and an actuator selectively overcomes the biasing element to engage the roller clutch and lock the inner and outer races to prevent relative rotation therebetween. The actuation disk and the case end includes a first portion adapted to provide initial axial surface to surface contact between the actuation disk and the case end when the actuation disk contacts the case end and a second portion adapted to provide an surface to surface contact only after deflection of the actuation disk under the force of the actuator, thereby providing a spring back response when the actuator is de-energized.

Abstract: A transfer mechanism is provided for controlling a magnitude of clutch engagement force exerted on a multi-plate clutch assembly operably disposed between input and output members. The transfer clutch includes an actuator fixed for rotation with the input member, a piston slidably disposed within a piston chamber of the actuator and selectively engaging the multi-plate clutch assembly, a pump in fluid communication with the piston chamber, and operably engaged with the input member and the output member. A rotational speed differential between the input member and the output member induces pumping action for pumping a magnetorheological fluid through the piston chamber. An electromagnetic coil is operably disposed between the piston chamber and the pump. The electromagnetic coil is selectively energized for manipulating a viscosity of the magnetorheological fluid to induce a back pressure within the piston chamber, thereby inducing axial movement of the piston for engaging the clutch pack.

Abstract: A wrap spring activated torque coupling is applied to a torque transmission coupling and/or a locking differential for a motor vehicle. The wrap-spring torque coupling allows for quick engagement and disengagement of an input member to an associated output member at large torsional capacities that exceed the limit of what is taught by prior art. The ability to quickly lock and unlock a vehicle differential under either a torsionally loaded or unloaded condition is realized by this application of the wrap spring activated torque coupling. Moreover, a two piece bi-directional wrap spring hub design is utilized that allows for simple turning and broaching operations for use in its manufacture, thereby eliminating a conventional deep annular counterbore that would require the use of much more expensive machining processes.

Abstract: A structure and a method for supporting an electromagnetic coupling (1) onto a vehicle body (347) is disclosed as being interposed between a center support bearing (37) remaining closer to a propeller shaft (319) and a center support bearing (37) remaining closer to a propeller shaft (321). The center support bearings (37, 37) are fixedly mounted to the vehicle body via shock absorbing members (35, 35), respectively.

Abstract: A hydraulically actuated torque-coupling device is provided for selectively actuating a secondary drive axle of an All-Wheel Drive motor vehicle when wheel slippage occurs with a primary axle. The torque-coupling device comprises a housing, an input shaft and an output shaft both rotatably supported within the housing, a selectively engageable friction clutch assembly for operatively coupling the input shaft to the output shaft, and hydraulic clutch actuator. The hydraulic actuator includes a hydraulic pump located within the housing 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 for selectively varying a release pressure of the pressure relief valve assembly based on a magnitude of an electric current applied thereto.