Abstract: A two-way clutch biasing assembly including a two-way clutch having an inner race attached to an input shaft and an outer race attached to an output shaft. The inner and outer races having inner cammed portions between them, with an engagement assembly interposed therein that is adapted to rotate bi-directionally thereby providing selective mechanical engagement between the races in either direction. A planetary gear assembly is provided having a ring gear, planetary gears on a carrier, and a sun gear that is adapted to rotate the engagement assembly within the two-way clutch. A drag clutch assembly is also slidingly connected to the carrier to hold the carrier stationary when the input shaft is stationary, such that sun gear is rotated by the plurality of planetary gears, thereby rotating the engagement assembly within the two-way clutch and providing a mechanical advantage in engaging the races together when the input shaft begins to move.

Abstract: An inter-axle differential capable of preventing a skid to achieve stable travel is provided. For this purpose, the inter-axle differential apparatus includes an inter-axle differential (13), an inter-axle differential lock (21), at least one rotation detector of a first rotation detector (27) for detecting rotational frequency of a transmission output shaft (24), a second rotation detector (28) for detecting rotational frequency of a front output shaft (25) of the inter-axle differential, and a third rotation detector (29) for detecting rotational frequency of a rear output shaft (26) of the inter-axle differential, and a controller (20) for detecting a sign of a skid occurring to driving wheels (2, 4) based on at least any one of the rotational frequency detected by the rotational detector and a rate of change with time of the detected rotational frequency and for outputting a differential lock signal to the inter-axle differential lock.

Abstract: The present invention relates to a control circuit for controlling the driving stability of a vehicle where the input quantities determining the course of track are input in a vehicle model circuit which determines at least on nominal value for a control quantity subject to parameters memorised in the vehicle reference model on the basis of a vehicle reference model reproducing the characteristics of the vehicle.

Abstract: To achieve a first object of the present invention, a starting time limit vehicle speed which preferentially permits a torque distribution to front and rear wheels at the time of starting of a vehicle is switched in accordance with a degree of a diameter difference. To achieve a second object of the present invention, when the vehicle makes a normal running with different-diameter tires mounted thereon, a front/rear wheel distribution torque caused by a front/rear wheel rotation speed difference owing to the different-diameter tires is limited by switching a torque gain depending on a degree of a diameter difference.

Abstract: A transfer case control system or apparatus 10 is provided for use on a four-wheel drive vehicle of the type having a transfer case 32, a front driveshaft 22 and a rear driveshaft 26. Transfer case control system 10 includes a conventional microcontroller or controller 40 having a memory unit 42 and operating under stored program control. Controller 40 is communicatively coupled to sensors 44, 46, 48, and to a transfer case 32. Controller 40 selectively generates a control signal having a proportional term or component and an integral term or component. The control signal is generated to transfer case 32 and controls the amount of torque provided to driveshafts 22, 26.

Abstract: A two-way clutch for allowing limited torque to be transferred until a roller clutch mechanism is forced to an engaged position. The present invention includes a roller clutch, with a torque generating device mounted thereon, including an actuator for producing an axial force onto a clutch pack. A torque transfer device is disposed between the torque generating device and the roller clutch. The torque transfer device is adapted to receive torque from the torque generating device and to transfer torque to the roller clutch. When a predetermined level of torque is produced by the torque generating device, the torque transfer device moves the roller clutch into an engaged position.

Abstract: An axle case assembly is provided with a speed sensitive torque coupling mechanism used to transmit torque from the ring gear to a planetary differential assembly. The differential assembly provides torque transfer proportional to the speed difference between the ring gear sub-assembly and a planetary gear set sub-assembly, wherein the invention splits a differential case assembly into two primary pieces and a speed sensitive mechanism is installed between each piece. The mechanism is entirely contained inside an axle differential case assembly. An optional limited slip device may be provided for the differential gears. The torque transmission coupling assembly eliminates the need for a center differential in the transfer case, i.e. an interaxle differential, thereby reducing the driveline complexity and cost without requiring a separate torque coupling in the transfer case or in-line with the driveline.

Abstract: A controllable, multi-mode, bi-directional overrunning clutch assembly and a mode shift system are adapted for use in a transfer case for transferring drive torque from a primary output shaft to a secondary output shaft so as to establish four-wheel drive modes. The clutch assembly includes a first ring journalled on a first rotary member, a second ring fixed to a second rotary member, and a plurality of rollers disposed in opposed cam tracks formed between the first and second rings. The first ring is split to define an actuation channel having a pair of spaced end segments. An actuator ring is moveable between positions engaged with and released from the end segments of the first ring. The shift system includes a moveable clutch actuator which controls movement of the actuator ring for establishing an on-demand four-wheel drive mode and a locked or part-time four-wheel drive mode.

Abstract: A differential device for 4WD vehicles having a reduced size and capable of being produced at lower costs makes it possible to select between a 2WD state, a differential-free 4WD state, and a differential-locked 4WD state. The differential device includes a differential case, a side gear, a hub, and a switching mechanism which establishes and interrupts a connection between each of the differential case, the side gear, and the hub. The switching mechanism includes, among other possible features, a first sleeve, a second sleeve which is separate from the first sleeve, and a pin. A sole actuator moves the second sleeve between first, second and third positions to establish the 2WD state, the differential-free 4WD state, and the differential-locked 4WD state.

Abstract: A viscous coupling having two rotatable parts in the form of a hub and a housing for the transmission of torque between the rotatable parts caused by a positive speed differential between the rotatable parts, which are supported inside one another, which are rotatable relative to one another around a common longitudinal axis, and which form an annular chamber which is filled with a highly viscous fluid and in which first coupling plates non-rotatably connected to the first one of the two rotatable parts, e.g. the hub, and second coupling plates non-rotatably connected to the second one of the rotatable parts, e.g. the housing, are arranged alternately in the longitudinal direction.

Abstract: A power transmission system for a four-wheel drive vehicle, comprising a differential mechanism having a torque sensing type differential limiting function. Further comprised are: a torque distribution mechanism for transmitting the torque to a front-wheel drive shaft connected to the front wheels or a rear-wheel drive shaft connected to the rear wheels; a first selective coupling mechanism for coupling the torque distribution mechanism selectively to one of two output elements of the differential mechanism; and a second selective coupling mechanism for coupling an input member and one of the output members, when the first selective coupling mechanism releases the coupling between the torque distributing mechanism and the front-wheel or rear-wheel side drive member, to integrate the differential mechanism as a whole thereby to establish a two-wheel drive state.

Abstract: A differential limiting mechanism produces a changeable differential limiting torque. A differential limiting mechanism operating lever is disposed so as to be operated and turned by a hand gripping a handgrip attached to a handlebar. The operating lever is interlocked with the differential limiting mechanism so that the differential limiting torque varies according to an angle through which the operating lever is turned. A lever stopping mechanism stops the operating lever at an angular position for producing a predetermined maximum differential limiting torque.

Abstract: A vehicle has a lockable differential. The lockable differential generally comprises an actuator and a locking mechanism. The vehicle also has a motor. The actuator, the motor or both are controlled according to a control routine that reduces wear on the components by reducing the likelihood that a locked differential will be requested when locking is not very practical. In one arrangement, actuation only occurs below a preset threshold speed and can occur through a specified range defined between the preset threshold and a second threshold. In another arrangement, the motor speed is controlled when actuation is desired such that motor speed is reduced to a lockable speed range.

Abstract: A full-time power transfer system is disclosed to include a transfer case having a clutch assembly arranged to control speed differentiation and torque biasing across an interaxle differential, sensors for detecting and generating sensor signals indicative of various dynamic and operational characteristics of the vehicle, and a controller for controlling actuation of the clutch assembly in response to the sensor signals. Upon the occurrence of traction loss, the clutch assembly is automatically actuated for limiting interaxle slip while transferring increased drive torque to the non-slipping driveline. Under a preferred adaptive control scheme, the actuated condition of the clutch assembly is controllably modulated between its non-actuated and fully-actuated limits for automatically varying the magnitude of speed differentiation and torque biasing across the interaxle differential in response to changes in the dynamic and operational characteristics of the vehicle.

Abstract: A driving force control device for a four-wheel drive vehicle including one pair of front or rear driven wheels which are driven directly by a prime mover and another pair of front or rear driven wheels which are driven via a hydraulic clutch, a first hydraulic pump which is driven by being operatively connected to the one pair of driven wheels, and a second hydraulic pump which is driven by being operatively connected to the other pair of driven wheels. The engagement force of the hydraulic clutch is controllable based on the difference in rotation of the first and second hydraulic pumps. The torque transmission to the other pair of the front or rear driven wheels can thus be controlled according to the driving conditions of the vehicle.

Abstract: An on demand vehicle drive system monitors vehicle performance and operating conditions and controls torque delivery to the vehicle wheels. The system includes a plurality of speed and position sensors, a transfer case having primary and secondary output shafts driving primary and secondary axles and a microcontroller. The sensors include a vehicle speed sensor, a pair of primary and secondary drive shaft speed sensors, and brake and driveline status sensors. The transfer case includes a modulating electromagnetic clutch controlled by the microcontroller which is incrementally engaged to transfer torque from the primary output shaft to the secondary output shaft. When the speed of either the front or the rear drive shafts overruns, i.e., exceeds, the speed of the other drive shaft by a predetermined value related to the vehicle speed, indicating that wheel slip is present, clutch current is incrementally increased to increase clutch engagement and torque transfer to the secondary axle.

Abstract: A torque transfer device for use on an all wheel drive vehicle. The torque transfer device includes a differential housing. The torque transfer device includes a clutch assembly rotatably supported within the differential housing. The torque transfer device also includes a pump assembly connected to the clutch housing on one side thereof. The torque transfer device also includes a hydraulic assembly in contact with the pump on the side opposite the clutch. The hydraulic assembly is rotationally stationary with respect to the pump assembly. The torque transfer device also includes an axle housing rotatably fixed with respect to the differential housing. The hydraulic assembly is in contact with the axle housing.

Abstract: A full-time power transfer system is disclosed to include a transfer case having a clutch assembly arranged to control speed differentiation and torque biasing across an interaxle differential, sensors for detecting and generating sensor signals indicative of various dynamic and operational characteristics of the vehicle, and a controller for controlling actuation of the clutch assembly in response to the sensor signals. Upon the occurrence of traction loss, the clutch assembly is automatically actuated for limiting interaxle slip while transferring increased drive torque to the non-slipping driveline. Under a preferred adaptive control scheme, the actuated condition of the clutch assembly is controllably modulated between its non-actuated and fully-actuated limits for automatically varying the magnitude of speed differentiation and torque biasing across the interaxle differential in response to changes in the dynamic and operational characteristics of the vehicle.

Abstract: A full-time power transfer system is disclosed to include a transfer case having a clutch assembly arranged to control speed differentiation and torque biasing across an interaxle differential, sensors for detecting and generating sensor signals indicative of various dynamic and operational characteristics of the vehicle, and a controller for controlling actuation of the clutch assembly in response to the sensor signals. Upon the occurrence of traction loss, the clutch assembly is automatically actuated for limiting interaxle slip while transferring increased drive torque to the non-slipping driveline. Under a preferred adaptive control scheme, the actuated condition of the clutch assembly is controllably modulated between its non-actuated and fully-actuated limits for automatically varying the magnitude of speed differentiation and torque biasing across the interaxle differential in response to changes in the dynamic and operational characteristics of the vehicle.

Abstract: The invention concerns a drive control for motor and utility vehicles. The speeds of the wheels and the steering angle are measured by means of sensors. Driving axle slip is determined by comparing the average peripheral wheel speeds of the driven and non driven axles and by taking into account the steering geometry. Driving force and finally chassis efficiency are determined by the slip with the assistance of standard characteristic lines. The efficiencies of all-wheel drive and rear-wheel drive are compared. The drive with the higher degree of efficiency is engaged.

Abstract: A four-wheel drive vehicle having a first hydraulic pump operated in operative association with the rotation of front wheels, and a second hydraulic pump operated in operative association with the rotation of rear wheels, such that a difference in rotational speed is produced between the front and rear wheels, a multi-plate clutch is brought into its engaged state by a hydraulic pressure generated by the hydraulic pumps, whereby the mode of the vehicle is shifted into a four-wheel drive mode. A torque cam mechanism is disposed between a clutch piston and clutch plates, so that when the difference in rotational speed is produced between the front and rear wheels, the torque cam mechanism produces an axial thrust force immediately to promptly bring the multi-plate clutch into its engaged state. The engagement of the multi-plate clutch is achieved with a sufficient engagement force by the hydraulic pressure thereafter produced by the hydraulic pump.

Abstract: A motor vehicle transmission has a differential assembly (17) in which one input, sun gear (39), of an epicyclic gear train can be selectively coupled by a sleeve (59) through a viscous coupling (55) to either an input, i.e. annulus gear (31), or to another output, i.e. carrier (36). Coupling the sun gear to the annulus gear gives a low resistance mode of operation and coupling the sun gear to the carrier gives a high resistance mode of operation. A locked mode where the annulus is locked to the sun gear is also described, together with a free mode where the viscous coupling is disconnected from both the annulus gear and the carrier. The sleeve is lined to the control of a range change gearbox to select the low resistance mode when a high range is selected for on-road use and a high resistance mode is selected when a low range is selected for off-road use.

Abstract: A device for a differential gear for vehicles having a driving mechanism capable of driving the vehicle and a steering mechanism capable of changing the direction of the vehicle, which differential gear has an input driving shaft, two output shafts connected to the vehicle's driving mechanism, at least one hydraulic pump capable of producing a hydraulic flow, and at least one hydraulic motor communicating with the hydraulic pump and arranged to the differential gear, capable of achieving a difference in rotational speed between the output shafts. The device is capable of regulating the hydraulic flow between the hydraulic pump and the hydraulic motor depending on the steering direction of the steering mechanism and the velocity of the vehicle.

Abstract: A transmission for a four-wheel drive vehicle having a multi-speed geartrain and power transfer mechanism incorporated into a common housing assembly. The multi-speed geartrain includes a input shaft, a mainshaft, and a plurality of constant-mesh gearsets arranged for selectively coupling the mainshaft to the input shaft for driven rotation at various speed ratios. The mainshaft can be selectively coupled to the power transfer mechanism for establishing two alternative power transmission routes. In particular, a range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to the input of an interaxle differential. The torque delivered to the interaxle differential is split between the front and rear drivelines to establish a full-time four-wheel drive mode. A transfer clutch is provided for automatically controlling slip and torque biasing between the outputs of the interaxle differential.

Abstract: A transfer case adapted for installation on a front-wheel drive vehicle having a transversely oriented engine and transaxle receives drive torque on a transferse axis and provides it to the rear differential on a longitudinal axis. The transfer case is driven through the front axle center differential cage. A drive chain delivers power through sprockets to a modulating or viscous clutch disposed behind and parallel to the front stub axles. The output of the clutch is provided to a bevel gear set which drives the rear prop shaft, rear differential and rear axles. The transfer case and rear prop shaft are preferably disposed along the longitudinal center line of the vehicle. Alternatively, the transfer case and the rear prop shaft may be disposed along an axis laterally offset but parallel to the longitudinal center line of the vehicle.

Abstract: A four-wheel drive system for a motor vehicle includes a transfer case through which power is continually transmitted to a first drive wheel pair and a clutch that controls a magnitude of torque transmitted to a second drive wheel pair in accordance with an electric current duty cycle applied to the clutch by a control unit that produces an output duty cycle in response to a range selected by the operator, the vehicle speed, and the position of the throttle that controls a power source driveably connected to the input side of the transfer case.

Abstract: When an accelerator pedal is released, or when a brake pedal is depressed and if braking force is lower than a reference braking force corresponding to a braking force immediately before causing a wheel lock, differential limiting force of a center differential is set to a predetermined value so as to retain an under-steer condition while engine brake is applied. When the brake pedal is depressed and if braking force is higher than the reference braking force, differential limiting force of the center differential is set to zero so as to assist an anti-lock brake system. Further, the reference braking force can be determined according to a road friction coefficient, a grade of road, a lateral acceleration and the like. Further, the predetermined value of the differential limiting force may be a constant value or may be a value corresponding to a front-to-rear weight distribution ratio.

Abstract: An engine drive torque is distributed to an extra wheel at a predetermined distribution ratio. When the vehicle makes a turn at low speed and when the torque distribution ratio to the extra drive wheel is high, a torsion is produced in the vehicle body, suspension and tires, etc., due to a rotation radius difference between the main and extra drive wheels. After the vehicle has stopped, and the engine is stopped, torque is no longer distributed to the extra drive wheel, the torsion is suddenly released and the vehicle vibrates. According to this invention, the release of torsion is performed gradually by decreasing the torque distribution ratio when the vehicle has stopped, with the engine still running in order to prevent this vibration.

Abstract: A system for controlling torque transfer in a motor vehicle includes a transfer case, a front inter-axle differential unit and a rear inter-axle differential unit. The transfer case is operative for automatically transferring torque between front and rear pairs of wheels. The front inter-axle differential unit is operative for automatically transferring torque between the wheels of the front pair of wheels. The rear inter-axle differential unit is operative for automatically transferring torque between the wheels of the rear pair of wheels. Under extreme operating conditions, the system is operative for delivering substantially all torque to a single tractive wheel.

Abstract: A transfer case includes a double overrunning or two-way clutch and torque limited centrifugal cone clutch disposed in mechanical parallel between a primary and secondary output of the transfer case. The double overrunning clutch includes a plurality of rollers disposed between concentrically arranged drive and driven members. The centrifugal cone clutch includes a preload or preset biasing spring which sets a minimal torque throughput, a plurality of weights which adjust the clutch force and thus torque throughput dependent upon the speed and stops which limit motion of the weights and thus determine the maximum clutch compressive force and torque throughput.

Abstract: An integrated system for automatically controlling the operation of both an automated mechanical transmission and a multiple speed axle assembly in a vehicle drive train assembly includes a transmission actuator for operating the transmission in any one of a plurality of transmission gear ratios. The system further includes an axle actuator for operating the axle assembly in any one of a plurality of axle gear ratios. An electronic controller is provided for operating the transmission in a desired one of the plurality of transmission gear ratios and for operating the axle assembly in a desired one of the plurality of axle gear ratios to provide a desired overall gear ratio for the vehicle. To accomplish this, the electronic controller is responsive to one or more input signals that represent operating parameters of the vehicle.

Abstract: A transmission for a four-wheel drive vehicle having a multi-speed geartrain and power transfer mechanism incorporated into a common housing assembly. The multi-speed geartrain includes a input shaft, a mainshaft, and a plurality of constant-mesh gearsets arranged for selectively coupling the mainshaft to the input shaft for driven rotation at various speed ratios. The mainshaft can be selectively coupled to the power transfer mechanism for establishing two alternative power transmission routes. In particular, a range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to the input of an interaxle differential. The torque delivered to the interaxle differential is split between the front and rear drivelines to establish a full-time four-wheel drive mode. A transfer clutch is provided for automatically controlling slip and torque biasing between the outputs of the interaxle differential.

Abstract: In a four wheel drive vehicle, when rear wheels which are principal drive wheels skid, first a traction control system is operated so as to reduce the drive power to the rear wheels. Thereafter the proportion of drive power apportioned to the front wheels which are auxiliary drive wheels is increased by a torque splitting control system. By doing this, skidding of a wheel due to delay in application of traction control is prevented.

Abstract: An adaptive torque control and distribution system for a motor vehicle having a transfer case, primary driveline and drive wheels and secondary driveline and drive wheels for operation in extreme off road conditions such as sand. The transfer case includes a modulating clutch and a lockup clutch disposed in parallel between its primary (rear) output and secondary (front) output. The system detects abnormally high magnitude and rapidly repeating wheel spin transients which are characteristic of operation in sand or similar highly randomly variable tractive conditions and overrides the on demand torque distribution program for a predetermined time interval. During this predetermined time interval, the transfer case lockup clutch is activated thereby coupling the primary and secondary drivelines and achieving a fifty-fifty torque split therebetween while the modulating clutch is inactive.

Abstract: A system for monitoring spinout conditions in a heavy vehicle driveline provides the ability to monitor the manner in which a driver operates a vehicle. For example, spin out conditions that occur with greater frequency than is normally expected indicates an inappropriate manner of operating the vehicle. Similarly, spinouts that have relatively excessive duration indicate inappropriate vehicle operation. The system includes a sensor device for detecting a spinout condition and a detector for detecting whether a differential lock has been engaged by the vehicle operator. An electronic controller gathers information from the sensor device and the detector and records information regarding each spinout including the frequency and duration. This information is then later provided to a service technician to determine whether the vehicle warranty provisions have been violated.

Abstract: A rotation transmission device is mounted in a drive train of a four-wheel drive vehicle to selectively distribute driving force to selected vehicle wheels according to the travel condition of the vehicle. This device includes an outer ring and an input shaft. A cylindrical face is formed on one of the opposed surfaces of the outer ring and the input shaft, while cam faces are formed on the other opposed surface to define a wedge-shaped space between the cylindrical face and each cam face. Rollers are mounted in pockets formed in a retainer mounted between the input shaft and the outer ring. An electromagnetic clutch is coupled to the retainer. A switch spring is mounted between the retainer and the input shaft. A two-way clutch is provided between the outer ring and the input shaft.

Abstract: A first power train (T1) for driving a pair of front drive wheels (Wf1, Wf2) comprises a transmission (4) connected to an engine (2) and a front drive train (41f) connected to the drive wheels, the front drive train including a final reduction gear (43), and a second power train (T2) for driving a pair of rear drive wheels (Wr1, Wr2) comprises a rear transfer train (11) branched from the first power train, between the transmission and the front drive train, and a rear drive train (41r) connected to the rear drive wheels.

Abstract: In a four wheel drive system for an automotive vehicle, a detected value .DELTA.V.sub.W of difference of rotating speed between the front and rear wheels is compared with a threshold .DELTA.V.sub.W0 determined in accordance with a pseudo vehicle speed V.sub.FF (S116, S213). As a result of this, when a determination is made that the pseudo vehicle speed V.sub.FF is in a directly connecting four wheel drive condition inhibiting range, a directly connecting four wheel drive condition inhibiting signal S.sub.N is sent out (S121), so that a front wheel side torque distribution instruction value T.sub.2 is determined as a value preventing the directly connecting four wheel drive condition. Thereby, in case of using of the different diameter wheel, a deterioration of stability and an increase of load of power train system caused by the directly connecting four wheel drive condition can be prevented.

Abstract: For automatically controlling a differential lock in drive axles of a motor vehicle, an arrangement has a lock coupling, an actuator for actuating the lock coupling, a plurality of rotary speed sensors associated with wheels of the vehicle for forming the rotary speed signal, a control unit for receiving the rotary speed signals and forming a control signal for controlling the actuator means, the control unit including computing means for computing a nominal rotary speed value associated with each of the wheels so that a computed nominal rotary speed value is determined continuously in dependence from a corresponding traveling condition, a first comparing unit for forming a difference rotary speed value from a comparison of a measured rotary speed value with the computed nominal rotary speed value, and a second comparing unit for forming the control signal so that when the difference rotary speed value exceeds a predetermined threshold value the lock coupling is engaged and when the difference rotary speed va

Abstract: A transfer case having a mechanically parallel overrunning clutch and centrifugal, speed proportional clutch provides improved handling characteristics especially in off-throttle driving conditions. The transfer case includes a one-way or overrunning clutch which provides drive from the rear driveline to the front driveline to rotate the front driveline and wheels at least as fast as the rear driveline and wheels. For example, the one-way clutch will be engaged when the rear drive wheels lose traction and attempt to overspeed the front drive wheels. The clutch overruns, however, if the front driveline and wheels are urged to overrun the rear driveline. The mechanically parallel speed responsive, i.e., centrifugal, clutch provides speed proportional engagement or coupling between the two drivelines and is particularly effective to reduce speed differences therebetween as its clutching and torque transfer effects are in direct proportion to the speed difference between the two drivelines.

Abstract: A rotation transmission device is mounted in a drive train of a four-wheel drive vehicle to selectively distribute driving force to selected vehicle wheels according to the travel condition of the vehicle. This device includes an outer ring and an input shaft. A cylindrical face is formed on one of the opposed surfaces of the outer ring and the input shaft, while cam faces are formed on the other opposed surface to define a wedge-shaped space between the cylindrical face and each cam face. Rollers are mounted in pockets formed in a retainer mounted between the input shaft and the outer ring. An electromagnetic clutch is coupled to the retainer. A switch spring is mounted between the retainer and the input shaft. A two-way clutch is provided between the outer ring and the input shaft.

Abstract: Principal components of an automobile driving system for a two-wheel drive vehicle including a torque converter, a belt-type variable-speed transmission, a front differential gear, a transmission case containing these components, a front drive shaft included in a transfer unit, a double-pinion planetary gear, a fixed shaft, a first friction coupling element and a second friction coupling element can be used as the principal components of an automobile driving system for a four-wheel drive vehicle. The automobile driving system for a four-wheel drive vehicle can be constructed by additionally incorporating third, fourth and fifth friction coupling elements, a rear differential gear and a power transmitting mechanism for transmitting power to the rear differential gear into the automobile driving system for a two-wheel drive vehicle.

Abstract: A method for the automatic locking of the differentials of an all-wheel driven vehicle, slip signals being formed which, as soon as they exceed a threshold value, initiate the driving of the respective differentials. In order to take into account the influence of the steering rolling radius, the change in the steering value is ascertained. From this, using a function determined by the geometry of the vehicle, an apparent slip is ascertained. From the respective apparent slip, corrected threshold values are determined and measured slip signals are compared with the corrected threshold values and, if necessary, the driving of the respective differential is initiated. The method can also be used on a vehicle having articulated-vehicle steering.

Abstract: A transmission for a four-wheel drive vehicle having a multi-speed geartrain and power transfer mechanism incorporated into a common housing assembly. The multi-speed geartrain includes a input shaft, a mainshaft, and a plurality of constant-mesh gearsets arranged for selectively coupling the mainshaft to the input shaft for driven rotation at various speed ratios. The mainshaft can be selectively coupled to the power transfer mechanism for establishing two alternative power transmission routes. In particular, a synchronized range shift mechanism is provided for establishing a high-range transmission route and a low-range transmission route from the mainshaft to a primary driveline to define a two-wheel drive mode. A portion of the drive torque delivered to the primary driveline can be transferred automatically through a transfer clutch to the secondary driveline to establish an on-demand four-wheel drive mode.

Abstract: In a vehicle which includes a front driveshaft for transferring motive power to a front set of wheels and a rear driveshaft for transferring motive power to a rear set of wheels and a clutch to control the amount of torque provided to the driveshafts, a method is provided to control the amount of power delivered to the front and rear driveshafts. The duty cycle of the clutch is monitored and it is determined whether the clutch duty cycle passes a first lower threshold and a second higher threshold, successively, a predetermined number of times within a calibratible time period. A 4 Hi Lock mode is entered if the clutch duty cycle passes the first lower threshold and the second higher threshold, successively, a predetermined number of times within the calibratible period.

Abstract: A traction control system for a four wheel drive vehicle including generating a first value corresponding to an average rotational speed of front wheels, generating a second value corresponding to an average of a rotational speed of rear wheels, comparing the first and second values, and generating a first signal corresponding to a difference between the first and second values, are provided. The first signal is used for transferring torque to the secondary axle if the rear wheels are rotating faster than the front wheels. The system also generates a second signal corresponding to a difference in speed between a first axle shaft and a second axle shaft of the front axle. The second signal is used for transferring torque to the other of the front axle shafts if the one of the secondary axle shafts is rotating faster than the other of the front axle shafts.

Abstract: A rotation transmission device is mounted in a drive train of a four-wheel drive vehicle to selectively distribute driving force to selected vehicle wheels according to the travel condition of the vehicle. This device includes an outer ring and an input shaft. A cylindrical face is formed on one of the opposed surfaces of the outer ring and the input shaft, while cam faces are formed on the other opposed surface to define a wedge-shaped space between the cylindrical face and each cam face. Rollers are mounted in pockets formed in a retainer mounted between the input shaft and the outer ring. An electromagnetic clutch is coupled to the retainer. A switch spring is mounted between the retainer and the input shaft. A two-way clutch is provided between the outer ring and the input shaft.

Abstract: A differential mechanism has a differential casing for receiving drive power from an engine and a pair of output members for distributing the received drive power to road wheel ends. A pair of drive power control mechanisms each respectively comprise a combination of a speed change mechanism and a friction clutch for a serial connection between the differential casing and either output member or between the output members and an actuator for actuating the friction clutch to be let in. A controller controls a pair of the actuators to have a pair of the friction clutches periodically let in and let out in an alternating manner with a relatively short period.

Abstract: A manual transmission for a four wheel drive vehicle having a driving force distributing apparatus is composed of a transmission gearing mechanism and a differential mechanism. The transmission gearing mechanism comprises an input shaft for transmitting driving force of an engine, an output shaft arranged on the same axis as the input shaft for outputting driving force of the transmission to the differential mechanism, a counter shaft arranged in parallel with the output shaft for transmitting driving force from the input shaft to the output shaft through transmission gears. The differential mechanism mounted at the rear end of the transmission mechanism on the same axis as the output shaft comprises a differential for distributing driving force of the transmission gearing mechanism into a front drive shaft and a rear drive shaft. Further, the differential mechanism includes a differential limiting mechanism for controlling a torque distribution ratio according to running conditions.

Abstract: A transmission for a four-wheel drive vehicle incorporating a multi-speed geartrain which delivers power to the front and rear drivelines through an interaxle differential. A lock-out clutch is provided to selectively inhibit speed differentiation across the interaxle differential. Additionally, a driveline disconnect system including a synchronizer clutch assembly is provided to allow one of the drivelines to be disengaged for establishing two-wheel drive operation.