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 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 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 torque-to-thrust apply mechanism for a torque-transmitting mechanism includes an input electric motor supplying torque to a first rotary to thrust ball and ramp mechanism which converts rotary motion to an apply force between an apply plate and a plurality of friction discs within a torque-transmitting mechanism. The mechanism also includes a second rotary-to-thrust mechanism which receives input rotation from the first apply member as a result of reaction torque. The rotation of the second mechanism results in additional thrust on the friction plates to amplify the apply force of the torque-to-thrust apply mechanism.

Abstract: A torque-to-thrust apply mechanism for a torque-transmitting mechanism includes an input electric motor supplying torque to a first rotary to thrust ball and ramp mechanism which converts rotary motion to an apply force between an apply plate and a plurality of friction discs within a torque-transmitting mechanism. The mechanism also includes a second rotary-to-thrust mechanism which receives input rotation from the first apply member as a result of reaction torque. The rotation of the second mechanism results in additional thrust on the friction plates to amplify the apply force of the torque-to-thrust apply mechanism.

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: Engagement characteristics of electromagnetic friction clutch pack assemblies disposed in, for example, motor vehicle transfer cases are improved, especially at the transition between static and dynamic friction modes, by superimposing a random noise signal on an otherwise smooth analog or stepped digital signal. The controller and driver for the clutch includes a random noise (signal) generator having an output which is superimposed on the controller output generated in response to signals from various sensors disposed on the vehicle. When the controller inputs cause clutch engagement in accordance with the controller software, an engagement signal comprising both a drive portion and a smaller random noise portion is supplied to the electromagnetic clutch operator. Improved, less perceptible clutch engagement action is thereby achieved.

Abstract: A power transfer device including a main clutch, a cam mechanism and an electromagnetic pilot clutch mechanism coaxially assembled within a cylindrical space between an external cylindrical rotary member and an internal rotary member, wherein an electromagnetic coil of the pilot clutch mechanism is applied with an electric current to produce pilot torque, the cam mechanism is applied with the pilot torque to produce thrust force in an axial direction, and the main clutch is engaged by the thrust force applied from the cam mechanism to effect drive connection between the rotary members. In the power transfer device, residual thrust force of the cam mechanism is electrically or mechanically decreased at an instance when differential rotation of the rotary members is reversed.

Abstract: In a power transmission apparatus, comprising: a sub-clutch apparatus, a main clutch apparatus and a cam apparatus, wherein the electromagnet is arranged in an inner diameter side of the main clutch apparatus.

Abstract: The present invention is directed to a clutch actuator assembly for a clutch pack wherein the clutch actuator assembly includes a lever rotatable about an axis, a drive mechanism that selectively rotates the lever about the axis, and a translating mechanism that receives input from the lever, converts the input to linear displacement, and is operably coupled to the clutch pack pressure plate to apply the linear displacement. The present invention is further directed to a clutch assembly and torque transferring mechanism having such a clutch actuator assembly.

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 coupling for a vehicle includes a pilot clutch 15, a main clutch 13, a pressing system 21 and a coupling mechanism 17. The pilot clutch 15 generates a pilot torque and is operated by operating means 19. The main clutch 13 connects torque members 11 and 9 and transmits transmitted torque. The coupling mechanism 17 operated by the pilot torque converts the pilot torque into a pressing force for coupling the main clutch 13 via the pressing system 21 by use of a cam thrust force thereof. The main clutch 13 is disposed outside the pilot clutch 15 in a radial direction, and respective members of the pressing system 21 are mutually positioned and designed to move unitarily in a pressing direction, thus sliding portions caused by the main clutch 13 is connecting and disconnecting are limited to being on a side of the main clutch 13.

Abstract: A dual mass flywheel and clutch system for minimizing torsional vibration levels during engine start-up and during low speed engine operation where the rotational moment of inertia of a clutch input assembly is minimized to raise the torsional natural frequency of the dual mass clutch system above the engine firing frequency when the clutch is disengaged to reduce the level of torsional vibration during engine start-up. After engine start-up, the dual mass clutch system is engaged and the torsional natural frequency of the clutch system returns to a lower frequency due to the rotation of the clutch output assembly thereby effectively reducing the torsional vibration levels in the vehicle driveline in a normal manner.

Abstract: A driveline master clutch assembly is disclosed where a unidirectional ball ramp mechanism is used to apply a clamping load to a clutch pack for frictionally coupling a prime mover such as an engine to a gear change transmission. The ball ramp mechanism includes index plates to limit the rotation of a control ring and an activation ring such that the energized ball ramp mechanism increases in separation distance to increase the clamping force on the clutch pack whenever there is slippage in the clutch pack irregardless of the direction of torque flow through the master clutch assembly.

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 driveline master clutch assembly is disclosed where a unidirectional ball ramp mechanism is used to apply a clamping load to a clutch pack for frictionally coupling a prime mover such as an engine to a gear change transmission. The ball ramp mechanism includes index plates to limit the rotation of a control ring and an activation ring such that the energized ball ramp mechanism increases in separation distance to increase the clamping force on the clutch pack whenever there is slippage in the clutch pack irregardless of the direction of torque flow through the master clutch assembly.

Abstract: A ball ramp mechanism is used to apply an axial force in the same irregardless of the direction of the flow of torque whenever there is relative rotation between an input shaft and an output hub using unidirectional grooves in both a control ring and an activation ring where a first index plate limits the rotation of the activation ring and a second index plate limits the rotation of the control ring relative to the input shaft. An electrical coil is used to induce a magnetic field in a coil pole to magnetically couple a coil armature to an intermediate plate and the intermediate plate to an activation plate to energize the ball ramp mechanism.

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: A transfer clutch includes a magnetorheological actuator which controls operation of a ball screw operator for controlling the magnitude of clutch engagement force exerted on a multi-plate clutch assembly that is operably disposed between an input member and an output member. The magnetorheological actuator includes an electromagnetic coil, and a rotor having a first segment retained in a sealed chamber filled with magnetorheological fluid. The ball screw operator includes a threaded screw mounted on the output member and which is splined to a second segment of the rotor, a threaded nut, a plurality of balls retained between the aligned threads of the screw and nut, and a drag spring providing a predetermined drag force between the screw and the output member. The multi-plate clutch assembly includes a drum driven by the input member, a hub driving the output member, and a clutch pack operably disposed between the drum and hub.

Abstract: In a power transmission apparatus, a sub-clutch apparatus is arranged between the input shaft and an intermediate rotary body, a main clutch apparatus is arranged between the intermediate rotary body and the output shaft, and a cam apparatus converting the frictional engagement force of the sub-clutch apparatus into the pressing force for the main clutch apparatus.

Abstract: A drive force transmission apparatus disposed within a differential carrier and adapted to drivingly couple first and second rotary shafts. The drive force transmission apparatus includes an outer casing coupled to the first rotary shaft, an inner shaft coupled to the second rotary shaft, a frictional clutch which enters a frictionally engaged state upon reception of a thrust force to thereby couple the outer casing and the inner shaft together, and an electromagnetic drive mechanism for generating the thrust force.

Abstract: A driving force transmission device transmits driving force between an outer case made of magnetic substance and inner shaft. A main clutch mechanism, an electromagnetic type pilot clutch mechanism and cam mechanism are arranged between the outer case and inner shaft. The main clutch mechanism transmits driving force between the outer case and inner shaft. The pilot clutch mechanism controls operation of the main clutch mechanism and comprises an electromagnet, an armature and a friction clutch. The cam mechanism amplifies output of the pilot clutch mechanism and transmits amplified output to the main clutch mechanism. The driving force transmission device further comprises a first regulation member and/or a second regulating member. The first regulating member adjusts a clearance between the cam mechanism and the armature to be more than a predetermined distance. The second regulating member adjusts an axial position of the friction clutch.

Abstract: A wet-type friction clutch plate surely keeps lubricant on a frictional slide face, stabilizes frictional torque transmission, and suppresses shuddering noise.

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: A preferred embodiment compound ball ramp clutch assembly for motor vehicle drive line components includes a force amplifying assembly having two ball ramp operators arranged in tandem. The clutch assembly includes a first ball ramp operator having opposed cam plates with load transferring balls, an electromagnetic coil, a rotor and an armature. When energized, the coil creates drag which causes separation of the plates of the first ball ramp operator which compresses a primary (pilot) clutch pack disposed in mechanical parallel with the cam plates and load transferring balls of a second ball ramp operator. A speed difference and drag across the second ball ramp operator compresses a secondary (main) clutch pack. Significantly increased torque carrying capacity is exhibited by such a compound or a tandem ball ramp clutch assembly.

Abstract: Drive system torsional vibration resonance while an engine is idling is prevented. An input clutch pack is connected to a rotating drive plate connected to the engine. The input clutch pack is formed from a drive side comprising an input drum, metal plates, and a retaining plate and from a driven side comprising an input clutch hub and facing plates. When the input clutch pack is disengaged, the inertial mass on the engine side with the engine serving as the vibration source, the coil spring, and the inertial mass on the drive side form a single-degree-of-freedom drive system torsional vibration model. By increasing the thickness in the axial direction of the metal plates, the drive side inertial mass is made to be 50% to 100% of the engine side inertial mass. As a result, drive system torsional vibration resonance during idling is prevented while the weight increase is kept to a minimum.

Abstract: A ball ramp mechanism is used to apply a clamping load to a clutch pack to rotationally couple an input shaft to an output shaft. The ball ramp mechanism is comprised of a control plate having a control extension radially extending therefrom and an activation plate having an activation extension radially extending therefrom and an intermediate plate disposed between the control extension and the activation extension where the control extension and the activation extension and the intermediate plate are frictionally rotationally coupled upon application of an electromagnetic field generated by a stationary coil acting through a rotating coil armature to activate the ball ramp mechanism. A gap sleeve contacts the control plate and the activation extension to limit the separation between the control extension, the intermediate plate and the activation extension.

Abstract: A limited slip differential assembly comprises a friction clutch assembly and a clutch actuator assembly including an actuator motor, a clutch actuator, and a gear module for drivingly coupling the actuator motor to the clutch actuator. The gear module includes a casing having a first mounting flange for fixing the casing to a differential housing and a second mounting flange for fixing the casing to the actuator motor, two gear support arms outwardly extending from the first mounting flange into the differential housing through an opening therein, a gear shaft supported by the gear support arms, and a pair of coaxial reduction gear members drivingly coupled to the gear shaft. One of the reduction gear members is drivingly coupled to the actuator motor and the other of the reduction gear members is drivingly coupled with the clutch actuator.

Abstract: The present invention relates to a power transmission system for an automatically engaging all-wheel drive vehicle that efficiently realizes all-wheel drive according to driving conditions. The power transmission system includes a rotary coupling mounted on a power transmission member for transmitting power that is output from an engine to front and rear wheels, the rotary coupling selectively transmitting the power to one of either the front wheels or the rear wheels, or to all four wheels. The rotary coupling includes a housing connected to an input member; a hub shaft connected to an output member; a multi-plate clutch mounted between the housing and the hub shaft; and a pressure assembly operated according to driving conditions to control the multi-plate clutch.

Abstract: An active bidirectional clutch for use on a vehicle includes an oil housing. The clutch also includes a flange rotatably supported with respect to the oil housing. The flange includes an input shaft that is rotatably fixed with respect to the flange and a coupling that is adjacent to the input shaft. The clutch also includes a plurality of rollers in contact with the input shaft and coupling. The clutch uses a roller cage that positions the plurality of rollers with respect to the input shaft and the coupling. The bidirectional clutch also includes a sleeve positioned around the input shaft, wherein the sleeve has a plurality of slots and the sleeve engages the roller cage.

Abstract: A rotating member, a main clutch, a pilot clutch, a yoke having an electromagnet fixed thereto, a cam-type amplifying mechanism, and a rear housing are mounted in a housing to form a housing assembly. An outer peripheral surface of the yoke of the housing assembly is fitted to a case in a fluid-tight manner so as to prevent rotation of the yoke. An inner peripheral surface of the yoke is fitted to an outer peripheral surface of a smaller-diameter rear housing portion in a fluid-tight manner. The housing assembly is thus mounted only in the case.

Abstract: An axle module for use in an automotive vehicle. The axle module includes a housing and a shaft rotatably supported within that housing. The axle module also includes a ring gear connected to the shaft. The axle module also includes a clutch pack housing engaged with an end of shaft while a side shaft joint is arranged within the clutch pack housing. The side shaft joint is connected to a side shaft which is further connected to a wheel of the automotive vehicle. A plurality of plates extend from the clutch pack housing and from the side shaft joint such that they overlap in an alternating manner with one another. The axle module also includes a motor which is used to control the transfer of an axial torque through the clutch pack housing and plurality of plates.

Abstract: A front or rear torque transfer module system for an all-wheel drive vehicle includes a housing containing two rotating shaft members connected by a clutch. The clutch is activated when a braking mechanism such as an electromagnetic, hysteresis or eddy current brake modulates the relative rotation between a clutch pressure plate and the second rotating shaft member. The difference in relative rotation forces two opposing ramped surfaces into opposition to induce the clutch pressure plate to compress a set of interleaved clutch discs thereby transferring rotational motion between the first rotating shaft member and the second rotating shaft member.

Abstract: In a power-split transmission for driving a first and a second axle of a motor vehicle, in the case of which transmission are located a first and a second output shaft (3, 4) and a friction clutch (12), the latter is intended to transmit a controllable torque. For this purpose, (a) for the action of pressure upon the pressure plate (29), there are provided two rotationally uncoupled ring parts (31, 32) which are coaxial to the friction clutch and at least one of which possesses ramps rising in the circumferential direction, (b) the two ring parts (31, 32) are supported in the axial direction and each possess a ramp lever (35, 36), the free end (37, 38) of which cooperates with a control unit (11) which moves the ramp levers in opposite directions, and (c) the control unit (11) having a rotatable control disk (40) with two slots, and the drive means being an electric geared 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: In a power transmission apparatus, comprising: a sub-clutch apparatus, a main clutch apparatus and a cam apparatus, wherein the electromagnet is arranged in an inner diameter side of the main clutch apparatus.

Abstract: In a power transmission apparatus, a sub-clutch apparatus is arranged between the input shaft and an intermediate rotary body, a main clutch apparatus is arranged between the intermediate rotary body and the output shaft, and a cam apparatus converting the frictional engagement force of the sub-clutch apparatus into the pressing force for the main clutch apparatus.

Abstract: A driving force transmission system comprising: a coupling case and a shaft arranged rotatably relative to each other; a pilot clutch and a main clutch for controlling a torque transmission between the coupling case and the shaft; an electromagnet for controlling the actions of the pilot clutch and the main clutch; and oil retaining the functions of the pilot clutch and the main clutch. This system further comprises a coupling case, a shaft, a rotor, and X-ring and an O-ring isolating a coupling oil chamber, in which the pilot clutch and the main clutch are arranged, liquid-tight from the surrounding space.

Abstract: A wet type friction clutch and an electromagnetic clutch is disclosed wherein a pilot clutch 61 is disposed in a magnetic flux path 95 of an electromagnet 57 and is kept between an armature 71 and the electromagnet 57. Upon excitation of the electromagnet 57, the armature 57 is retracted to allow the pilot clutch 61 to be coupled. The pilot clutch 61 includes a plurality of clutch plates 87, 89 which are interleaved with respect to one another for sliding movements. Adjacent clutch plates 87, 87A, 87B, 89, 89A, 89B, 89C, 89D, 89E, 89F are formed with oil guide passageways 86, 96, 98, 106, 108, 110, 114 to create a hydrodynamic pressure effect to allow the clutch plates to be separated with a limited drag torque.

Abstract: Friction clutch plates have a first face exhibiting a surface finish of about Ra 0.5 to 0.9 and a second face having friction material secured thereto. The clutch plates are manufactured by rolling steel to a thickness of about 0.030 inches (0.76 mm) which exhibits a mill finish of about Ra 0.64 to 1.14. The rolled steel is then stamped to form circular clutch plate blanks. One surface is then smoothed, preferably by polishing, so that peaks and sharp points are flattened or removed. The resulting surface finish includes irregular relatively flat and smooth regions interspersed with and separating irregular recesses or pits and exhibits a surface finish of about Ra 0.5 to 0.9. Friction material is then secured to the opposite face of the clutch plates. The clutch plates are used in multiple plate friction clutch packs which are intended for use in dual clutch front and rear axle assemblies and motor vehicle transfer cases.

Abstract: A dual ball ramp actuator having a control ring acting with a pressure plates to supply an axial clutch clamping force to a differential clutch assembly where the ball ramp paths follow overlapping eccentric grooves that can be actuated in both the forward and reverse directions. The dual ramp feature doubles the effectiveness and sensitivity when compared to a single ramp system. The overlapping eccentric ball ramps increase (effectively double) the angular travel distance while reducing the ramp angle (in half). The forward and reverse feature provides clutch actuation in both the forward and reverse directions. The dual ramp, 3-piece sandwich construction permits the central control ring to roll up on two sets of balls on each side. This structure doubles the axial travel available to compress a disc pack and lock up the differential with the same ball ramp angle when compared to a single ramp system involving only two ramp plates.

Abstract: A coupling for a vehicle includes a pilot clutch 15, a main clutch 13, a pressing system 21 and a coupling mechanism 17. The pilot clutch 15 generates a pilot torque and is operated by operating means 19. The main clutch 13 connects torque members 11 and 9 and transmits transmitted torque. The coupling mechanism 17 operated by the pilot torque converts the pilot torque into a pressing force for coupling the main clutch 13 via the pressing system 21 by use of a cam thrust force thereof. The main clutch 13 is disposed outside the pilot clutch 15 in a radial direction, and respective members of the pressing system 21 are mutually positioned and designed to move unitarily in a pressing direction, thus sliding portions caused by the main clutch 13 is connecting and disconnecting are limited to being on a side of the main clutch 13.

Abstract: An electromagnetic wet clutch system includes operation members configured to magnetically work. The system includes a set of clutch plates configured to engage by the operation members. The set of clutch plates includes first plates with first sides. Respective one of the first sides is configured to contact respective one of the operation members. At least one of the first sides is boundary-lubricative.

Abstract: There is provided with a first clutch. A second clutch is for controlling fastening and releasing operation of the first clutch. The first clutch and the second clutch are radially differently and axially correspondently positioned each other.

Abstract: A drive force transmission apparatus disposed within a differential carrier and adapted to drivingly couple first and second rotary shafts. The drive force transmission apparatus includes an outer casing coupled to the first rotary shaft, an inner shaft coupled to the second rotary shaft, a frictional clutch which enters a frictionally engaged state upon reception of a thrust force to thereby couple the outer casing and the inner shaft together, and an electromagnetic drive mechanism for generating the thrust force.

Abstract: A front or rear torque transfer module system for an all-wheel drive vehicle includes a housing containing two rotating shaft members connected by a clutch. The clutch is activated when a braking mechanism such as an electromagnetic, hysteresis or eddy current brake modulates the relative rotation between a clutch pressure plate and the second rotating shaft member. The difference in relative rotation forces two opposing ramped surfaces into opposition to induce the clutch pressure plate to compress a set of interleaved clutch discs thereby transferring rotational motion between the first rotating shaft member and the second rotating shaft member.

Abstract: An electromagnetic clutch having a solenoid coil (80), a coil housing (81) disposed surrounding the solenoid coil (80), an armature plate (82) disposed facing the side of the coil housing, and a clutch mechanism. The current flowing to the solenoid coil (80) is controlled so as to control the clamping of the armature plate (82) to the coil housing (81), and the clamping force acting on the armature plate is used to control the engagement of the clutch mechanism. There is also a lubricating oil supply channel (63) for supplying lubricating oil from the inside in the radial direction into a gap between the coil housing and the armature plate, and oil reservoir holding lubricating oil to be supplied into the gap is formed around the inner periphery of the portion where the coil housing faces the armature plate.

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 method of returning an electromechanical axial setting device, particularly suited for friction couplings. The axial setting device includes two setting rings centered on a common axis, one of which is axially held, with the other one being axially displaceably mounted, and one of which is rotationally fixedly held in a housing so as to be prevented from rotating, with the other one being rotatingly drivable. On their respective end faces facing one another, the two setting rings each include an identical multitude of circumferentially extending grooves. Each of the grooves, in a plan view of the end faces, define a depth which rises in the circumferential direction. Pairs of grooves in the setting rings each accommodate a ball. The rotatingly drivable setting ring is connected to an electric motor in respect of drive. The axially displaceable setting ring is loaded by pressure springs towards the axially held setting ring.