Abstract: A viscous shear coupling for distributing torque between front and rear axles of an all-wheel drive vehicle is provided which comprises a housing, a set of inner blades interdigitating with a set of outer blades, the inner and outer blades being axially spaced apart from each other and axially slidably mounted within the housing, a viscous liquid located within the housing, an adjusting piston within the housing which is axially displaceable so as to adjust the axial distance between adjacent inner and outer blades. The viscous shear coupling further includes a control pressure circuit for delivery of a control pressure fluid to the adjusting piston, a control valve for regulating the delivery of the control pressure fluid to the adjusting piston, and a control device (e.g., a microprocessor) which calculates a desired adjusting piston speed based on driving conditions and adjusts a valve current delivered to the control valve in order to obtain the desired adjusting piston speed.

Abstract: A power take-off adaptor for use in a two-wheel drive vehicle equipped with automatic transmission for supporting a standard power take-off unit, thereby providing power take-off capabilities. A synchronizing shift arrangement is provided for shifting a clutch sleeve following speed synchronization between an output member and an input member of the adaptor.

Abstract: A four wheel drive working vehicle having a front wheel transmission switchable between a standard position for driving front wheels at substantially the same speed as rear wheels, and an accelerating position for driving the front wheels at a higher speed than the rear wheels; right and left side brakes for acting on the right and left rear wheels, respectively; a control device for switching the front wheel transmission from the standard position to the accelerating position when the front wheels are steered in excess of a first predetermined angle rightward or leftward from a straight running position, and for operating one of the right and left side brakes inwardly with respect to turning of the vehicle when the front wheels are steered in excess of a second predetermined angle rightward or leftward from the straight running position; and a governor for governing operation of the control device in response to a running speed of the vehicle.

Abstract: A power take-off adaptor for use in a two-wheel drive vehicle equipped with automatic transmission for supporting a standard power take-off unit, thereby providing power take-off capabilities.

Abstract: A power transfer device adapted for use in combination with a primary transmission for an automotive vehicle, including a housing, a first output shaft rotatably mounted on the housing and having an input end for drive connection to an output shaft of the power transmission and an output end for drive connection to a first set of road wheels, a second output shaft rotatably mounted within the housing in parallel with the first output shaft and having an output end for drive connection to a second set of road wheels, a drive member rotatably mounted on the first output shaft, a driven member mounted on the second output shaft for rotation therewith and being drivingly connected to the drive member, a center differential in the form of a planetary gear unit mounted on the first output shaft and having a first output element in drive connection to the first output shaft and a second output element for drive connection to the drive member, and a changeover mechanism arranged between the planetary gear unit and th

Abstract: An engine and a first final drive are disposed proximate a first set of road wheels, while the transmission and a second final drive are disposed proximate the second set of road wheels. A torque tube which operatively interconnects the engine containing section with the section in which the transmission is disposed, houses a first propeller shaft which transmits engine torque to the transmission, and a hollow second propeller shaft which is disposed coaxially about the first one, and which transmits torque back from the transmission to the engine containing section for application to the first set of road wheels.

Abstract: The present invention provides a motor vehicle traction control system for providing on-demand four-wheel drive under certain tractive and operational conditions. The traction control system permits the vehicle operator to choose between operation in the conventional two-wheel drive and four-wheel drive mode or the "on-demand" four-wheel drive mode. Moreover, the traction control system is operable for disabling the on-demand four-wheel drive feature upon the vehicle operator subsequently shifting into either of the two-wheel drive and the four-wheel drive modes.

Abstract: The present invention provides a motor vehicle traction control system for providing on-demand four-wheel drive under certain tractive and operational conditions. The present invention is operable for disabling the on-demand four-wheel drive feature upon the vehicle operator subsequently shifting into the four-wheel drive mode.

Abstract: A power transmitting system for a vehicle includes a rotatable input shaft for introducing driving power into the system, a rotatable first output shaft for transmitting the driving power from the system, and a rotatable second output shaft for also transmitting the driving power from the system. A transmitting member is rotatably mounted on the first output shaft and for rotating the second output shaft, a clutch mechanism is disposed adjacent to the transmitting member and mounted on the first output shaft for engaging the transmitting member with the first output shaft. An actuator is provided for actuating the clutch mechanism. A compact power transmitting system can be obtained.

Abstract: The invention is directed to an arrangement for controlling a braking force applied to each of the road wheels of a part time four-wheel drive vehicle depending upon a braking condition, with a hydraulic braking pressure supplied to each of wheel brake cylinders through pressure control valves respectively. The pressure control valves are controlled by the braking force controller into which output signals of wheel speed sensors are fed. A deceleration of the vehicle is detected by a deceleration sensor. In a counter, counted is the number of repetitions of decrease of the wheel speed of each road wheel down to below a predetermined standard speed and recovery of the wheel speed up to and over the standard speed. The value counted in each road wheel during a predetermined period of time in the counter is compared with a predetermined value in a comparator.

Abstract: The invention is directed to an arrangement for controlling a braking force applied to each of road wheels of a rear drive vehicle depending upon a braking condition, with a hydraulic braking pressure supplied to each of wheel brake cylinders through pressure control valves respectively. The pressure control valves are controlled by the braking force controller into which output signals of wheel speed sensors are fed. In a first determination unit, it is determined if at least one of the front road wheels is on a road surface of a coefficient of friction lower than a predetermined value, and determined if the front wheel speed of one of the front road wheels has reached to a peak wheel speed. And, in a second determination unit, it is determined if a difference between the front wheel speed and rear wheel speed is less than a predetermined speed.

Abstract: A power transmitting system of a four-wheel drive vehicle having primary driven wheels driven directly by a prime mover, and subsidiary driven wheels driven through a hydraulic clutch. The power transmitting system comprises a first hydraulic pump driven in operative association with the primary driven wheels and a second hydraulic pump driven in operative association with the subsidiary driven wheels. Each hydraulic pump has a pair of ports which serve as an intake and a discharge with the functions of such ports being reversed between forward and backward movement of the vehicle. A first oil passage connects the intake port of one pump with the discharge of the other pump and a second oil passage connects the discharge of the one pump with the intake of the other pump. Third and fourth oil passages connect the first and second oil passages, respectively, with a working hydraulic pressure chamber in the hydraulic clutch.

Abstract: A differential limiter for a vehicle is provided with a hydraulic multi-disc clutch for limiting a differential operation between at least two wheels, an inhibitor switch for detecting a gear position of a transmission mechanism, and controller for changing a differential limiting force by the clutch in accordance with a change in transmission position detected by the inhibitor switch.

Abstract: The present invention relates to a vehicle four wheel drive torque transfer case having a friction clutch which is selectively engaged when it is desired to place the transfer case in a four wheel drive operating mode. The transfer case includes an input shaft which is connected to supply torque to a rear output shaft. A multi-disc friction clutch is connected between the input shaft and a front output shaft for supplying torque to the front output shaft. A planetary gear assembly includes a sun gear, a carrier a planet carrier connected to the input shaft, and a ring gear coupled to drive the front output shaft. The multi-disc clutch is interposed between the sun gear and the ring gear and is engaged to inhibit any rotation of the planet carrier relative to the ring gear and thereby transfer torque to the front output shaft. The planetary gear assembly functions as a .sctn.'torque multipler" and this reduces the torque capacity requirements for the clutch.

Abstract: A power transmitting system for a four-wheel drive vehicle includes a first hydraulic pump driven interlockingly with the rotation of front wheels, a second hydraulic pump driven interlockingly with the rotation of rear wheels, and a hydraulic clutch for connecting the front wheels and rear wheels. The hydraulic clutch is adapted to be brought into an engaged state by an increase in oil pressure based on the difference between the amount of oil discharged from one of the hydraulic pumps and the amount of oil drawn into the other hydraulic pump. The hydraulic clutch, first hydraulic pump and second hydraulic pump are arranged in that sequence from the front toward rear of the vehicle on an axis extending longitudinally of the vehicle to maximize the air cooling effect on the hydraulic clutch and minimize the length of oil passages between the two hydraulic pumps.

Abstract: The present invention provides a motor vehicle traction control system for providing on-demand four-wheel drive under certain tractive and operational conditions. The present invention is operable for disabling the on-demand four-wheel drive feature upon the vehicle operator subsequently shifting into the four-wheel drive mode.

Abstract: To ensure the benefits of four-wheel drive when the vehicle is accelerating or when the front wheels are slipping, and to eliminate the disadvantage of undesirably transmitting the braking force to the rear wheels when the vehicle is decelerating or when a braking action is applied to the vehicle, the front wheels and the rear wheels are coupled with each other when the rotational speed of the front wheels is higher than that of the rear wheels, but this coupling is disconnected when the rotational speeds of the front and rear wheels are substantially identical or when the rotational speed of the rear wheels is higher than that of the front wheels.

Abstract: A four wheel drive system for a vehicle comprises a transverse power unit, a first (front) differential unit, an angular drive unit for changing the direction of torque path, a propeller shaft, and a second (rear) differential assembly between left and right permanent drive (rear) wheels which are always connected with the power unit through the differential case of the first differential unit, the angular drive unit, the propeller shaft and the second differential assembly. The first differential unit is provided between left and right nonpermanent drive (front) wheels. One of the nonpermanent drive wheels is simply connected with one side gear of the first differential unit by an axle shaft. The other nonpermanent drive wheel is connected with the other side gear of the first differential unit through a coupling unit, such as an orifice coupling, which can vary a driving torque distribution between the front and rear wheels by varying a transmission torque therebetween.

Abstract: A power transfer device having a center differential gear unit for use in a four-wheel drive vehicle of part time four-wheel drive type of the present invention comprises: an intermediate shaft which is rotatably provided around a rotary shaft, which rotary shaft is driven to transmit the driving power of an engine and connected with one of the output elements of the center differential gear unit, and which is detechably connected with the rotary shaft through the first clutch mechanism; and an output shaft which is rotatably provided around the intermediate shaft and detachably connected with the intermediate shaft through the second clutch mechanism having a synchro-mesh unit, wherein the transmission can be optionally changed over among the two-wheel drive state in which the center differential gear unit is locked, the four-wheel drive state in which the center differential gear unit is locked, and the four-wheel drive state in which the center differential gear is released, by moving the sleeve in the fir

Abstract: An internal disconnect mechanism for a planetary gear differential permits operation in either an engaged mode, wherein a driving connection is provided therethrough, and in a disengaged mode, wherein no driving connection is provided. The differential includes a case which is rotatable about an axis having first and second spur gears disposed therein, each adapted to be connected to an output shaft for rotation therewith. A first plurality of planetary gears mounted for rotation within the case mesh with the first spur gear and are axially immovable. A second plurality of planetary gears mounted for rotation within the case mesh with the second spur gear. Unlike the first planetary gears, however, the second planetary gears are axially movable between engaged and disengaged positions. In the engaged position, each of the second planetary gears meshes with a corresponding one of the first planetary gears. Thus, the differential functions in a normal manner.

Abstract: A restricting device for a differential is provided in a transaxle. A fluid-operated restricting clutch is provided adjacent a differential and disposed between a differential case and a corresponding axle so as to restrict differential operation of the differential. Clutch pressure of each clutch is controlled in accordance with driving conditions of a vehicle.

Abstract: A front axle drive assembly is disclosed which requires less lateral distance than known prior art assemblies. The drive is preferably for use in four wheel drive vehicles having an offset differential case. In such systems, the differential case is offset toward one side from the vehicle center line to accommodate the engine at the center line. An axle half on the offset side thus has reduced lateral space. The invention includes the use of a planetary system, requiring relatively little lateral space to split torque toward the two front wheels, thus providing additional lateral space for the axle half on the offset side. A constant velocity universal joint mounted between the planetary drive and the offset side axle half is received within the differential case. The lateral space savings resulting from the use of the planetary system allows the offset side axle half to be longer, providing benefits to the vehicle suspension system.

Abstract: A shift apparatus for shifting a transfer case between a High-Range operating mode and a Low-Range operating mode. The shift apparatus includes a sector plate supported within the transfer case for rotation about an axis. A range pin member extends into a range slot formed in the sector plate. The range pin member is adapted to move a first shift fork in response to selective rotation of the sector plate between first and second positions corresponding to the High-Range operating mode and the Low-Range operating mode of the transfer case. The range slot has a first camming edge provided for moving the range pin and first shift fork toward the first position upon rotation of the sector plate in a first direction, and a second camming edge for moving the range pin and first shift fork toward the second position in response to rotation of the sector plate in a second direction.

Abstract: A hub clutch device for connecting and disconnecting an axle and a wheel in a part time four-wheel drive vehicle is disclosed closed. The hub clutch device is provided with an outer race secured to a vehicle body, an inner race having a flange portion secured to the wheel and a hub portion provided with a gear portion at a peripheral inner portion, defining a fluid passage with the axle, and a roller member positioned between the outer race and the inner race. A movable wall is positioned inside of the hub portion. The movable wall defines a sealed chamber with the hub portion and is movable in an axial direction of the axle. The sealed chamber communicates with the fluid passage. A sliding gear always engages the gear portion of the hub portion and is axially movable according to the motion of the movable wall to engage a gear part of the axle to connect the axle with the wheel in a rotational direction.

Abstract: An automotive transmission system of the present invention comprises a transmission mechanism housed in a transmission case and operatively connected to an engine, and a hydraulically operated speed mode change mechanism and a hydraulically operated shuttle mechanism both operatively connected to the transmission mechanism. The hydraulically operated speed mode change mechanism is provided at the inlet side of the transmission mechanism. The hydraulically operated shuttle transmission mechanism is provided at the output side of the transmission mechanism and submerged in oil contained in the lower portion of the transmission case.

Abstract: A clutch assembly for automotive vehicle four-wheel drives either in association with an axle disconnect or wheel hub incorporates a power shift mechanism which can be remotely activated either when the vehicle is static, in motion and during either forward or reverse direction of movement to positively drive the clutch members into and out of engagement with one another. The power shift mechanism includes sealed envelopes in the form of expandable and contractable compartments which in response to a remote control valve will positively shift the clutch members into and out of engagement, and the members will remain in the shifted position without the continued application of force until positively shifted away from that position by the power shift mechanism. In the alternative, a spool-like shifter may be utilized with positive locking elements which will lock the clutch members in the engaged and disengaged position at the end of travel of the shift mechanism.

Abstract: A four wheel drive system for a vehicle includes comprising a power plant for producing a driving force, a front wheel driving mechanism for transmitting the driving force to drive right and left front wheels, a rear wheel driving mechanism for transmitting the driving force to drive right and left rear wheels, and right and left wheel clutches provided in one of the driving mechanisms for controlling the amount of the driving force transmitted to the wheels. A cut-off clutch is provided for controlling the driving force transmitted to the wheels of the one of the driving mechanisms, and a control device causes the cut-off clutch to engage before the wheel clutch is engaged. The driving force is transmitted sequentially rather than instantly from the cut-off clutch, the wheel clutches and to the wheels so as to suppress the torque shock creative in connection with a change in the drive condition.

Abstract: A transfer device for a four wheel drive motor vehicle is disclosed, which comprises an input shaft; a rear wheel output shaft arranged coaxial with the input shaft; a front wheel output shaft arranged in parallel with the input shaft; a center differential for distributing torque, applied thereto from the input shaft, to both the rear and front wheel output shafts through rear and front torque transmitting ways respectively; a differential control device operatively interposed between the rear and front torque transmitting ways to control a slip which may occur between the rear and front wheel output shafts; and a torque transmitting mechanism for transmitting the distributed torque from the center differential to the front wheel output shaft, wherein the center differential, the torque transmitting mechanism and the differential control device are supported by and aligned along the rear wheel output shaft in this order, and the rear wheel output shaft is supported by a bearing at a position between the torq

Abstract: A process for converting a motor vehicle to a free towing motor vehicle. The process includes the steps of removing an axle between the differential and one of the driven wheels and replacing it with a pair of stub axles with a connect/disconnect lock therebetween. In order to tow the vehicle, the connect/disconnect lock is moved to the unlocked position so that the driven wheels may turn freely.

Abstract: The present invention provides a motor vehicle cold shift assist system for selectively and automatically connecting the non-driven wheels to its associated axle drive mechanism under certain operational and temperature conditions for counteracting the inertial loading acting on the transfer case synchronizer clutch mechanism. The present invention substantially reduces the shift resistance encountered upon the vehicle operator subsequently shifting into the four-wheel drive mode during cold weather conditions.

Abstract: The present invention provides a motor vehicle cold shift assist system for selectively actuating an axle connecting mechanism to automatically connect the non-driven wheels to its associated axle drive mechanism immediately following synchronization for counteracting the inertial loading acting on the transfer case synchronizer clutch mechanism. The axle connecting mechanism is actuated prior to the transfer case being locked in the four-wheel drive mode. As such, the present invention substantially reduces the shift resistance and gear clash encountered upon the vehicle operator shifting into the four-wheel drive mode during cold weather conditions.

Abstract: An all wheel drive system for a motor vehicle is normally set up to operate in a two wheel drive mode except in vehicle operating situations where increased traction is desired. A drive shaft of a drive line is connected to front and rear axles through respective speed adjusters. A front speed adjuster provides for transmitting a rotational speed to the front drive axle that is slower than a rotational speed transmitted by the rear speed adjuster to the rear drive axle. At least one overrunning clutch is interposed in the drive line to a pair of front drive wheels for permitting the front drive wheels to be rotated out of engagement with the drive line by motion of the vehicle.

Abstract: The device engages the four wheel drive transmission of a vehicle which comprises two transmission shafts for the rear wheels and the front wheels, a clutch installed along a front shaft and adapted, if engaged, to couple the shafts for rotation together, and a drive transmission geometry such that mechanically, with the clutch engaged, the mechanical transmission causes the front wheels to be driven slightly faster than the rear wheels. The device includes two coupling halves adapted to connect two portions of the front shaft mechanically with the possibility of relative rotation, an element adapted to translate between two end positions corresponding to positive and negative relative rotation between the coupling halves, a sensor for detecting the movement of the element, and an electric central control unit to which the sensor is connected and adapted to control engagement or disengagement of the clutch automatically.

Abstract: To simplify propeller shaft supporting structure and to reduce propeller shaft vibration when a viscous coupling and a clutch mechanism are both provided on a propeller shaft of a 4WD vehicle, the power transmission apparatus comprises a housing rotatably supported to receive power; a differential gear disposed on one side of and within the housing; a viscous coupling disposed on the other side of and within the housing; and a clutch for transmitting power from the housing to the differential gear via the viscous coupling when engaged, and transmitting no power from the housing to the differential gear when disengaged.

Abstract: A diaphragm control is disclosed for a free-wheeling hub assembly that selectively engages a four-wheel drive. A venting arrangement is disclosed for the diaphragm chamber of the free-wheeling hub assembly. The venting arrangement extends through the body of the free-wheeling hub assembly to a space within the engine compartment of the vehicle thus ensuring that the vent will not become clogged thus preventing the venting of the diaphragm chamber. Venting of the diaphragm chamber is important in predicting the pressure within the diaphragm chamber and thus the engagement of the free-wheeling hub assembly.

Abstract: A four-wheel vehicle drive system, comprising an engine having an output shaft in a lateral direction of the vehicle, a power transmission gear unit including transmission input and output shafts having axes of rotation parallel with the engine output shaft, a final reduction gear rotatable about an axis parallel with the transmission input and output shafts, the transmission output shaft being in driving engagement with the final reduction gear, a gear housing rotatable with the final reduction gear, a main transaxle casing having enclosed therein the transmission gear unit, final reduction gear and gear housing, an auxiliary transaxle casing secured to the main transaxle casing, a first wheel drive gear unit to split driving power from the final reduction gear into two components and including a differential gear assembly enclosed in the auxiliary transaxle casing and operative to transmit one of the power components to a pair of road wheels, a second wheel drive gear unit enclosed in the auxiliary transaxl

Abstract: A control apparatus of a remote type free wheel hub clutch includes an inner sleeve integrally rotatable with a wheel axle, a clutch ring integrally rotatable with the free wheel hub clutch, an actuating arrangement for changing the two-wheel and four-wheel driving operations by engaging or disengaging the clutch ring with the inner sleeve in response to a transfer shift position. The transfer shift position actuates a discriminating circuit for changing over from two-wheel driving operation to four-wheel driving operation or vice verse.

Abstract: A transfer unit for a four-wheel drive vehicle includes a low-gear/high-gear shifting section and a two-wheel drive/four-wheel drive section. Both sections use gears with beveled portions and a synchronizer blocker ring to synchronize the rotation of gears before they are coupled to each other. This synchronization allows the vehicle to be shifted from low-gear to high-gear or from two-wheel drive to four-wheel drive while the vehicle is in motion without damaging the components of the transfer unit.

Abstract: The operation device of a transmission in accordance with the present invention has a lock mechanism which can lock a shift rod in either a high speed range or a low speed range in a transfer in response to a detection signal when a control lever is positioned at a parking range, and has also alarm means for raising an alarm in response to a detection signal when the transfer is at a neutral position. When a vehicle is parked with the control lever being in the parking range, a driver can recognize the state of the transfer by the alarm if the transfer is at the neutral position, and shifts the shift rod to the high or low speed range by operating the transfer lever. The lock mechanism operates in the high or low speed range and a full driving system is connected so that the vehicle can be kept stopped and self-run of the vehicle on a slope or the like can be prevented.

Abstract: An electrically actuated free wheel hub apparatus includes an axle tube, a wheel hub arranged about the axle tube and operated in response to the position of a drive transfer mechanism. An electric motor is disposed in a body fixed to the wheel hub and an axle shaft is interior to the axle tube. A control device control transmittal of power between the axle shaft and the wheel hub by a clutch mechanism. A syncromesh device is provided in the drive transfer mechanism so that each rotation of a front wheel side and a rear wheel side can be synchronized and a delay device transmit current to the motor after the completion of synchronizing.

Abstract: A control system for a four-wheel drive vehicle with a continuously variable transmission having a drive pulley having a hydraulically shiftable disc and a hydraulic cylinder for operating the disc, a driven pulley having a hydraulically shiftable disc and a hydraulic cylinder, and a pressure regulator valve for regulating pressure of oil supplied to the hydraulic cylinders. A hydraulic actuator is provided for engaging a transfer clutch for establishing four-wheel driving. The pressure regulator valve has a pressure level changing port to increase the pressure of oil supplied to the cylinders. A solenoid operated valve is provided for supplying the oil regulated by the pressure regulator valve to the hydraulic actuator and to the pressure level changing port or for draining the actuator and the port. An orifice is provided in an inlet side of the solenoid operated valve.

Abstract: A transfer case for a four wheel drive vehicle providing a drive range planetary gear set selectively positionable at a low speed output position, a high speed output position and a neutral position; having a dual planetary inter-axle differential gear set axially spaced from the range planetary gear set. The differential gear set is selectively positionable to provide a two-wheel drive mode to a first output and a full-time four-wheel drive mode with differential action between the first output and a second output. A viscous fluid clutch is selectively connected between the first and second outputs for modifying torque division therebetween whereby the viscous clutch is disconnected upon shifting into the two-wheel drive mode.

Abstract: A drive arrangement for a selectively engageable wheelset includes a clutch and a freewheel arranged in series, one behind the other, between a transmission and the selectively engageable wheelset. The clutch is designed as an overload release clutch, so that overloading of the drive to the selectively engageable wheelset is avoided when the freewheel is engaged. In addition, the clutch will permit interruption of the drive to the selectively engageable wheelset completely and as long as desired. The freewheel can be locked as a function of various operating conditions or upon demand.

Abstract: In a four-wheel drive work vehicle selectively drivable in a standard four-wheel drive mode, an accelerated four-wheel drive mode and in a two-wheel drive mode, the invention provides an improved drive-mode switching operability through a linearly operable link mechanism for operatively connecting one operational system for directly operating a shift fork member with another operational system for operating the same via a cam member connected to a steering wheel.

Abstract: A dog clutch mechanism for use as a clutch for switching drive power in a four-wheel-drive vehicle has a case, first and second rotatable shafts rotatably supported coaxially in the case for transmitting a relative torque between front and rear wheels of the vehicle, and a dog clutch comprising a dog piece having first dog teeth and fixedly mounted on the first rotatably shaft and a hub having second dog teeth capable of axially meshing with the first dog teeth and axially slidably mounted on the second rotatable shaft. The dog clutch is selectively engageable for transmitting the relative torque between the first and second rotatable shafts. The first and second dog teeth having respective meshing tapered surfaces for producing thrust forces acting on the hub and tending to move the hub in a direction away from the dog piece when the vehicle is braked while a relative forward torque is being transmitted between the first and second rotatable shafts through the dog clutch.

Abstract: A multiple driven axle vehicle, such as a four-wheel drive recreational vehicle having its front, steerable wheels being optionally driven by providing double acting overrunning clutches in the hubs of the front wheels. A transmission mechanism is provided for driving the front, optionally driven wheels slower than the driving surface otherwise drives those wheels so that the slower driven wheels overrun and do not engage when the steerable wheels are turned as the vehicle is driven through a turn, thereby eliminating the need for a differential between the steerable wheels and between the front and rear wheels. The overrunning roller clutches of the optionally driven hubs desirably include an intermittent friction apparatus operative between the roller cage and the vehicle chassis to intermittently exert a force tending to retard rotation of the cage with respect to the chassis, thereby indexing the roller cage and rollers to the forward or reverse engagable position.

Abstract: In a part-time four-wheel drive vehicle, and electric control apparatus for a transfer device in drive connection to a front or rear differential is arranged to permit selection of the four-wheel drive mode at the transfer device during travel of the vehicle in the two-wheel drive mode only in a condition where travel speed of the vehicle and temperature of lubricating oil in the differential are in a predetermined allowable region. The allowable region is defined to permit engagement of a clutch mechanism in the transfer drive mode without causing any heavy load acting thereon.

Abstract: A free wheel hub system comprises a free wheel hub mechanism disposed between a drive shaft and an axle hub supported by a spindle and a flexible print circuit disposed between the inner face of the spindle and the outer face of the drive shaft to control an electric element in the free wheel mechanism.

Abstract: A free wheel hub system comprises a free wheel hub mechanism disposed between a drive shaft and an axle hub supported by a spindle, an electric motor mounted on a hub body accommodating the free wheel hub mechanism, a brush case mounted on the hub body and accommodating bushes connected to the electric motor, and slip-rings mounted on the spindle and contacting the bushes. The brush case is fixed to the hub body before the hub body is attached to the axle hub.

Abstract: A torque distribution deciding control unit and an oil hydraulic clutch having opposite disks are provided. The clutch is disposed in a power transmitting system for four-wheel drive. One of disks is operatively connected to one of side gears of a central differential through a gear train and the other of the disks is operatively connected to the other side gear of the central differential through another gear train, whereby torque is transmitted to front and rear wheels at a distribution ratio. Loads on wheels such as weights on front and rear axles are detected. The control unit operates the clutch so as to distribute the torque at a ratio in accordance with loads on both axles.