Abstract: A power transmission apparatus for four-wheel drive vehicle which uses a hydraulic pump to absorb a rotational speed difference caused between front and rear wheels or left side and right side wheels to thereby materialize the four-wheel drive state and which is provided at a fixed housing with a variable throttle for adjusting oil pressure at the hydraulic pump. The variable throttle is adjustable of a degree of its opening by brake oil pressure generated by the braking action during the drive operation of an electromagnetic actuator or oil pressure introduced into a power cylinder disposed in a steering mechanism. Also, outside the fixed housing are provided fins for dissipating the heat content of operating oil at the hydraulic pump. Furthermore, on the slidable contact surface of a casing of the hydraulic pump with the fixed housing is provided sealing means for preventing the operating oil in the hydraulic pump from leaking therefrom.

Abstract: The power transmission apparatus comprises a center differential gear, a first inner front wheel drive hub connected to the center differential gear, a second outer rear wheel drive hub also connected to the center differential gear coaxially with the first hub, a ring gear fixed to the second hub, a pinion gear coupled to a propeller shaft and in mesh with the ring gear at a gearing position above the axis of the ring gear, and in particular a lubrication structure including a rotary cover member fixed to the second hub and formed with plural oil stirring projections, an oil sump formed in an inner surface of an apparatus housing, and an oil passage formed in a pinion gear housing.

Abstract: A differential is provided between a left and a right wheel of a motor vehicle for distributing an output torque of a transmission to the left and right wheels. A fluid operated multiple-disk clutch is provided for restricting the differential operation of the differential. A speed difference between the left and right wheels is calculated. The fluid operated multiple-disk clutch is operated in accordance with the speed difference, in such a manner that the restricting magnitude increases with an increase of the speed difference.

Abstract: A structure of vehicle power train having an engine situated lengthwise in a vehicle and a transmission disposed in the side of the engine in parallel comprises a front differential unit, which distributes a power outputted from the transmission to right and left front wheels, disposed in front of transmission in the longitudinal direction of the vehicle and between the engine output shaft and transmission output shaft in the widthwise direction of the vehicle. The centroid of the power train is positioned to the rear of the front wheels and accordingly, a load on the front wheels is reduced without lengthening a wheel base. By disposing the power train to the front of the transmission, the passenger compartment is widened. The overall height and length of the power train in the longitudinal direction of the vehicle is decreased, and the power train becomes compacted.

Abstract: The present invention is directed to an electronic actuator for use in a vehicle transmission such as a four wheel drive transfer case. In one preferred embodiment, the transfer case includes two separate electronic actuators, a range shift actuator which is utilized to effect shifting of the transfer case between high range, neutral, and low range drive positions, and a clutch actuator which is utilized to control engagement of a clutch between two wheel drive, automatic ("on demand" four wheel drive), and "part time" four wheel drive operating modes. The range shift actuator includes a rotary electric motor coaxially mounted relative to a rear output shaft of the transfer case, and a linear screw for translating the rotational movement of the motor shaft to selective axial movement of a range shift sleeve.

Abstract: In a transfer for use in a transaxle for a four-wheel drive vehicle, a transfer shaft for transmission of power to rear wheels is drivingly connected to a ring gear which is in turn directly connected with a pinion gear in such a manner that a center axis of the pinion gear intersects a center axis of the ring gear at right angles and in such a manner that the center axis of the pinion gear is offset upward from the center axis of the ring gear.

Abstract: A clutch mechanism for the drive train of a four-wheel drive vehicle for controlling the application of braking power between the front and rear wheels as applied through the drive train. A driving shaft is connected to a driven shaft through a roller clutch assembly and the driven shaft is coupled to a wheel set equipped with anti-lock brakes. The driving shaft has a drive cam race and a driven shaft has a cylindrical race. A cage carries the clutch rollers and is provided with drag shoes biased against a fixed drag ring. The rollers captured by the cage continuously drag against the rotative urging of the driving shaft whereby the rollers engage the cylindrical race with the driving shaft inducing driving rotation of the driven shaft, and disengage with the driving shaft inducing braking rotation of the driven shaft.

Abstract: A central differential is provided for distributing an output torque of a transmission to front wheels and rear wheels of a vehicle. A fluid-operated restricting device is provided for restricting the differential operation of the central differential. The central differential is arranged to distribute a larger torque to the rear wheels than to the front wheels. A slip ratio of the rear wheels is calculated in dependency on rear-wheel speed and vehicle speed. The fluid-operated restricting device is operated in accordance with the slip ratio, in such a manner that the restricting magnitude increases with an increase of the slip ratio.

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: The invention relates to a drive assembly for driving the wheels of a four wheel drive vehicle. The drive assembly comprises a propeller shaft 8 consisting of two portions 9, 10. Furthermore, the propeller shaft 8 comprises a viscous coupling 14 arranged at one end of the intermediate bearing 13 and a joint 15 arranged at the other end of the intermediate bearing 13 and non-rotatingly connected to the viscous coupling 14. Such a propeller shaft 8 ensures quiet running of the bearings of the assembly and prevents the joint and viscous coupling from influencing each other.

Abstract: The present invention is a method for controlling the change-over between two and four-wheel drive modes of a vehicle, wherein the two-wheel drive mode is smoothly changed to the four-wheel drive mode during acceleration in the two-wheel drive mode.

Abstract: A control system comprises a clutch for limiting a differential action between left and right drive wheels or varying a driving torque distribution between front and rear drive axles of a four wheel drive vehicle, a sensor group and a controller for controlling an engagement force of the clutch to control the differential limiting force or the torque distribution. The sensor group senses a decelerating condition of the vehicle, a vehicle lateral acceleration and a vehicle speed. The controller increases the clutch engagement force, so as to restrain tack-in, in accordance with the lateral acceleration when the vehicle is in a decelerating operation and the lateral acceleration is high. When the vehicle speed increases, the controller increases a rate of increase of the clutch engagement force with respect to the lateral acceleration to improve both of a high speed cornering stability and a low speed steering response.

Abstract: A four-wheel drive vehicle has a center differential which transmits the output torque of a power plant to both front and rear wheels in such a manner as to permit the front and rear wheels to rotate at different speeds. A differential control system has a differential rotation limit member which acts on the center differential to limit differential rotation of the front and rear wheels to a degree which is determined according to the difference in rotational speed between the front and rear wheels. The degree of limitation on the differential rotation of the wheels is determined according to the difference in rotational speed between the front and rear wheels based on first characteristics when the rotational speed of the front wheels is higher than that of the rear wheels and based on second characteristics when the rotational speed of the rear wheels is higher than that of the front wheels. The first and second characteristics are set separately from each other.

Abstract: A drive assembly for a four wheel drive vehicle, which drive assembly, during forward driving, automatically assumes a freewheeling position if the speed of the dependent wheel axle is higher than that of the permanently driven axle, with the four wheel drive function otherwise being maintained with a reduced driving torque, even during reversing, the drive assembly providing the freewheeling unit with a second viscous coupling which is connected in parallel and whose torque transmitting capacity is smaller than, or equal to, that of the first viscous coupling.

Abstract: An anti-lock braking system for a two-axle all-wheel drive vehicle having two intra-axle differentials and an engageable central inter-axle differential comprises a wheel sensor associated with each of the wheels for determining the rotational behavior of each of the wheels, and a four-channel electronic control circuit for providing individual wheel regulation. The electronic control circuit also detects whether the central differential is engaged or not and whether a malfunction has occurred in one of the channels. If one of the regulating channels has a malfunction and the central differential is not engaged, the electronic control circuit switches off regulation only in the malfunctioning channel. If, however, the central differential is engaged when a malfunction in one of the regulating channels has occurred, then the electronic control circuit switches off both the malfunctioning channel as well as an intact channel associated with a diagonally opposite wheel.

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 system for controlling torque distributed to front wheels and rear wheels of a motor vehicle comprises a planetary gear device including a first sun gear connected to an output shaft of a transmission, a carrier, first and second planetary pinions coupled with each other and rotatably supported on the carrier, and a second sun gear disposed between a front torque transmitting member and a rear torque transmitting member. The first planetary pinion is engaged with the first sun gear, and the second planetary pinion is engaged with the second sun gear. A fluid operated multiple-disk clutch is disposed between the carrier and the rear torque transmitting member so as to restrict the differential operation of the planetary gear device.

Abstract: A traction control system is provided which is applicable to a four-wheel drive vehicle in which a torque split system is incorporated. The torque split system is operable to distribute engine torque to front and rear wheels by an engine torque distribution ratio of front to rear wheels variable based on a difference in rotational speeds between the front and rear wheels. The traction control system is responsive to a slippage ratio of the rotational speeds of the wheels to a vehicle speed greater than a preselected threshold to reduce engine torque to control the traction of the wheels. Therefore, the traction control is effectively carried out while ensuring yaw control of a vehicle body by means of the torque split control.

Abstract: A transfer device for a four wheel drive motor vehicle is shown, 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; an auxiliary transmission disposed about the input shaft, the auxiliary transmission having low and high speed gear stages; a center differential disposed about the rear wheel output shaft at a position adjacent the auxiliary transmission; a switch device arranged between the auxiliary transmission and the center differential, the switch device being cable of connecting the auxiliary transmission and the center differential while keeping one of the low and high speed gear stages of the auxiliary transmission, wherein the switch device is so constructed as to surround the center differential.

Abstract: A full time four wheel drive system has a housing in the vicinity of an engine and a transmission, a central differential gear assembly and a viscous coupling assembly containing a front differential gear assembly. The central differential gear, front wheel differential gear, and viscous coupling assemblies are disposed in parallel relationship within the housing for uniformly distributing the load of axle and drive shafts according to the road conditions. The system has a simple structure and economically uses the space in the engine compartment.

Abstract: A control method for four wheel drive vehicles in which the front and rear wheels are not mechanically linked controls the drive torque to the vehicle wheels in proportion to vehicle loading and road surface friction coefficients in response to front and rear wheel speeds and front and rear wheel accelerations thereby reducing wheel spin.

Abstract: In an all-wheel driven field tractor whose front-axle differential (6) and rear-axle differential (15) are permanently driven in arable land by output shafts (2 and 3) of a gear change (1) so that a rigid connection exists between front and rear axles, the higher speeds of the front axle (7) appearing when cornering must be compensated. Besides, a mechanism for compensating the axle speeds must be adapted to be integrated in the field tractor without substantial constructural changes. For this purposse there is situated between the crown gear (12) and the differential cage (14) of the rear-axle differential (15) a clutch (16) designed as a control slip clutch having its slip status regulated according to the parameters of the track radius to be executed and/or the traction needed.

Abstract: A plate for a viscous shear coupling has inner and outer peripheries and slots which extend partly across the radial dimension between the peripheries. Between each adjacent pair of slots is a land and this is deformed out of the general plane of the disc to provide oppositely inclined surfaces.

Abstract: A viscous coupling for a motor vehicle which may be connected or disconnected under load and which, in a reliable and interference-free way and with a short delay time, selectively permits the transmission or interruption of the driving force relative to the wheels of the rear and/or front axle, including a locking ring which is axially movable between two switching positions and may be moved into one of the two switching positions against the returning force of a spring by a force-actuated setting member which includes a firmly connected annular tongue which consists of a low-remanence ferromagnetic material and which may be transferred in an annular gap selectively loaded with a magnetic flow and formed by a soft iron core, with the axial length of the annular gap being greater than or equal to the axial distance covered by the setting member between the two switching positions.

Abstract: A power transmission apparatus for vehicles for transmitting a driving force by coupling an input shaft and an output shaft of a hydraulic pump to respective driving shafts of front and rear wheels of a four-wheel drive vehicle, wherein a throttle member which is located on the axis of a rotor and a casing interlocking respectively with the input and output shafts, rotated with interlocking with one of the rotor and casing and disposed movably along the axis to change the hydraulic fluid discharge passage area of the hydraulic pump responsive to its movement, and a driving unit which includes a magnetic member coupled coaxially to the throttle member and a coil installed around the magnetic member and supported nonrotatably, and moves the throttle member by movement of the magnetic member in connection with excitation of the coil are provided.

Abstract: A control system comprises a clutch for limiting a differential action between left and right drive wheels or varying a driving torque distribution between front and rear axles of a 4WD vehicle, a sensor group and a controller for controlling an engagement force of the clutch to control the differential limiting force or the torque distribution between the front and rear drive wheels. The sensor group includes an accelerator position sensor and a lateral acceleration sensor. The controller increases the clutch engagement force as the speed of increase of the accelerator opening degree increases, and increases the rate of increase of the clutch engagement force with respect to the increasing speed of the accelerator opening degree when the lateral acceleration increases.

Abstract: A limited slip differential for a vehicle comprises a friction clutch disposed between a differential gear mechanism and a drive wheel axle, a clutch control cylinder for coupling and decoupling the friction clutch, a normally closed type solenoid valve for charging compressed air to the cylinder from a pressure air source and a normally opened type solenoid valve for discharging compressed air from the cylinder to the air. The normally closed type and normally opened type solenoid valves are operated by a control unit in response to a low .mu. road start, a low .mu. road run, a straight run and a brake so as to charge and discharge compressed air to and from the cylinder and thereby to control air pressure in the cylinder. A power device for a vehicle is composed by adding an engine control cylinder disposed in an acceleration control mechanism and an engine control valve for charging and discharging compressed air to the cylinder, and wherein during a low .mu.

Abstract: A four-wheel drive vehicle derived from a transversely mounted front engine-front drive system incorporates an improved steering gear rack and transfer pinion arrangement in which an axis of a transfer pinion is disposed higher than an axis of a transfer ring gear or differential gear of a transaxle and a steering gear rack is disposed lower than the transfer pinion.

Abstract: In a four-wheel-drive motor vehicle of transversely-disposed engine type, an engine and a transmission are disposed so as to be longitudinally offset from each other and to locate a gravitational center thereof in a rearward position of an axle of front wheels, and in addition an output shaft of the transmission and a center differential are disposed coaxially. With this arrangement, imbalanced weight distribution of the vehicle body on front wheels can be corrected, and a longitudinally-compact layout of the power transmission device can be obtained. Further, a height of a bonnet can be lowered.

Abstract: The distribution of drive power produced by a drive power source is controlled in a four-wheel-drive motor vehicle having main drive wheels and auxiliary drive wheels. Drive powers produced by the drive power source are independently regulated and transmitted to the left and right auxiliary drive wheels. While the drive power distribution ratio between the main and auxiliary drive wheels is maintained at a suitable value, the drive powers are variable distributed between the left and right auxiliary drive wheels by a drive power distribution control system. The drive power distribution control system determines the drive power distribution ratio between the left and right auxiliary drive wheels depending on a detected lateral acceleration exerted to the motor vehicle, and transmits the drive powers to the left and right auxiliary drive wheels according to the determined drive power distribution ratio.

Abstract: A power transmitting apparatus on a four-wheel-drive motor vehicle can distribute and transmit drive power from a power unit to front and rear drive road wheels such that the rotational speeds of the front and rear drive road wheels can differ from each other.

Abstract: A driving force distribution control system for a vehicle includes a torque distributing clutch for varying a driving force transmitted to a secondary drive wheels in response to a control signal, sensors for determining a wheel speed difference between the wheel speed of primary drive wheels and the wheel speed of the secondary drive wheels, and a longitudinal acceleration, and a control unit for controlling the clutch engagement force of the torque distributing clutch by producing the control signal. The control unit has a first control mode for normally controlling the clutch engagement force in accordance with the wheel speed difference, and a second control mode for controlling the clutch engagement force in accordance with the longitudinal acceleration so as to prevent undesired hunting when a wheel spin of the primary or secondary drive wheels is detected.

Abstract: A power distribution control system system takes a strategy for adjusting power distribution to vary control mode in order to avoid influence of variation of wheel speed difference between a primary driving wheel directly or permanently connected to a vehicular prime mover, i.e. an automotive internal combustion engine and thus having greater inertia and an auxiliary driving wheel having smaller inertia. For this, occurrence of hunting in power distribution control is detected. As long as hunting is not detected, the wheel speed difference dependent power distribution control mode is selected for controlling power distribution depending upon a wheel speed difference between the primary and auxiliary wheels.

Abstract: A rear transmission device of a vehicle with four driven wheels includes a box for transmitting power to the rear wheels, mechanically coupled to a power unit having an axis transverse to the vehicle body, a rear differential and a longitudinal linkage joining the two boxes. The box for transmitting power to the rear wheels is mounted to oscillate about a transverse axis parallel to the axis of the power unit and is joined to the housing of the rear differential by a rigid tube containing a transmission shaft. This assembly is thus integral with and articulated on the power unit. This arrangement constitutes a comparatively simple transmission device which is compact and can be fabricated at a low production cost.

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 four-wheel drive system comprises a first drive train that is mechanically engageable for transmitting a driving force from an engine to a set of front wheels and a second drive train that is provided with a viscous coupling for transmitting a driving force from the engine to a set of rear wheels by way of the viscous coupling. The second drive train is constructed so as to satisfy the relation that the speed of rotation of an input shaft of the viscous coupling divided by the speed of rotation of the front wheels is larger than the result of the speed of rotation of an output shaft of the viscous coupling divided by the speed of rotation of the rear wheels.

Abstract: There is disclosed a device for driving four wheels of a car at all times. In this device, a differential is provided between the left front wheel shaft and right rear wheel shaft and likewise a differential is also provided between the right front wheel shaft and left rear wheel shaft so that said two differentials can be driven by the same driving source.

Abstract: In a two-way clutch comprising an outer race having a plurality of roller receiving portions each formed by a pair of bisymmetrical arch-shaped cam surfaces, rollers disposed in the roller receiving portions, and a cage having support portions for the rollers and disposed on the inner periphery side of the outer race, the cage has a portion extending in the direction of a rotary shaft and clutch shoe receiving portions radially provided on the extending portion, and clutch shoes slidably fitted in the clutch shoe receiving portions have a sliding surface displaced by a centrifugal force resulting from the rotation of the clutch and sliding relative to a member outside the clutch.

Abstract: A central differential comprising a planetary gear device is parallel to front axles of a motor vehicle, and coaxially to a transfer shaft of a transfer device. The planetary gear device comprises a first sun gear connected to an output shaft of a transmission, a carrier, first and second planetary pinions integral with each other and rotatably supported on the carrier, and a second sun gear. The first planetary pinion is engaged with the first sun gear, and the second planetary pinion is engaged with the second sun gear. A fluid operated multiple-disk clutch is disposed coaxial to the central differential so as to restrict the differential operation of the planetary gear device.

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 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: To provide symmetrically wide inner spaces near two front or rear wheels of an automotive vehicle in which an engine and a transmission are arranged in series in the vehicle transversal direction, a first large-sized viscous coupling is disposed near a small-sized front or rear differential gear to limit the differential motion thereof; and a second small-sized viscous coupling is disposed near a large-sized center differential gear to limit the differential motion thereof. The center differential gear is disposed on the transmission side to differentially distribute engine power to front and rear wheels, and the front or rear differential gear is disposed on the engine side to further differentially distribute engine power distributed by the center differential gear to right and left wheels.

Abstract: A driving power transmission system for transmitting a driving power to front tires and rear tires, wherein a torque transmission device is disposed within a drive line for controlling transmissive torque transmitted to the tires. The torque transmission device is provided with a rotational housing to which a driving power from an engine is applied, a cylindrical shaft which is drivingly connected to the tires. The housing receives a clutch mechanism for transmitting a rotational torque from the housing to the cylindrical shaft, a piston located adjacent to the clutch mechanism and a pressure generating mechanism having an input rotational shaft for generating a pressure so as to actuate the clutch mechanism through the piston.

Abstract: A four-wheel-drive motor vehicle with a transversely-disposed engine of such construction that a front differential which distributes motive power from a center differential to the right and left front wheels is arranged on the front axle and in the rear of the front differential, an engine and a transmission are arranged. By this arrangement, one-sidedness of the vehicle body weight to the front wheels can be relieved.

Abstract: A hydraulic transmission coupling apparatus which is used instead of a center differential or a viscous coupling being usually mounted between a front wheel drive shaft and a rear wheel drive shaft of a four-wheel drive vehicle, and transmits driving force existing between the two shafts. The hydraulic transmission coupling apparatus is provided with a vane-type hydraulic pump which generates hydraulic pressure corresponding to a relative rotation speed difference of the two drive shafts and a variable throttle valve being disposed in the passage connecting a discharge port of the hydraulic pump with a tank, whose opening area varies according to the hydraulic pressure generated by the hydraulic pump, thereby driving force to be transmitted being increased or decreased steeply as the rotation speed difference becomes larger.

Abstract: A differential limiting force control system for controlling a slip limiting force by controlling an engagement force of a clutch assembly of a limited slip differential provided between left and right drive wheels of a vehicle includes a control unit having a basic control section for increasing the differential limiting force with increase of a vehicle speed, and an adjusting section for decreasing the differential limiting force when a steering angle is equal to or lower than a predetermined angle, or when a steering angular speed is equal to or higher than a predetermined angle.

Abstract: A central differential comprising a planetary gear device is coaxially mounted on one of the axles of a motor vehicle. The planetary gear device comprises a first sun gear connected to an output shaft of a transmission, a carrier, first and second planetary pinions integral with each other and rotatably supported on the carrier, and a second sun gear. The first planetary pinion is engaged with the first sun gear, and the second planetary pinion is engaged with the second sun gear. A fluid-operated multiple-disk clutch is disposed so as to restrict the differential operation of the planetary gear device.

Abstract: A system for controlling torque distributed to front wheels and rear wheels of a motor vehicle. A planetary gear device including a first sun gear connected to an output shaft of a manual transmission, first and second planet pinions integral with each other, a carrier provided to rotatably support the pinions and operatively connected to the front wheels, and a second sun gear operatively connected to the rear wheels is disposed to distribute the torque to front wheels and rear wheels. The first planetary pinion is engaged with the first sun gear, and the second planetary pinion is engaged with the second sun gear. A fluid operated multiple-disk clutch selectively connects two of the first sun gear, the carrier and the second sun gear so as to restrict the differential operation of the planetary gear device.

Abstract: A motor vehicle such as a four-wheel drive vehicle having a first axle shaft which is driven by a drive source and a second axle shaft which is driven by the same drive source, each of a pair of wheels associated with the second axle shaft being powered by way of individual variable torque transmitting devices, further comprising: a steering condition sensor; and a control unit which reduces a torque transmission ratio of one of the variable torque transmitting devices corresponding to the inner one of the wheels of the second axle shaft when the steering condition sensor has detected a steering angle greater than a prescribed value. Thereby, the problem of the tight turn braking can be avoided without losing the advantages of four-wheel drive.

Abstract: In the four-wheel-drive motor vehicle of transversely-disposed type, a front differential and a center differential are arranged coaxially on the axle line of front wheels, and an engine and a transmission are disposed transversely to the vehicle body in the rear of these differentials. This arrangement can relieve one-sided action of the vehicle body weight on the front wheels.