Abstract: A differential drive for use on a vehicle to control the transfer of torque between the front and rear axles of a vehicle. The differential drive includes a rotatably driven differential housing supported in a housing. The differential drive also includes a differential gear set arranged and supporting in the differential housing. The differential gear set has at least two side shafts gears and at least two differential gears. The differential drive also includes a torque distribution device having a viscous transmission. The viscous transmission has an inner hub and an outer casing. The inner hub is connected to a first side shaft. The outer casing is connected to one of the side gears. The viscous transmission also connects the output of the first side shaft to one of the side shaft gears.

Abstract: A motor vehicle interaxle differential including a bevel gear design and utilizing an interaxle differential housing having a one-piece construction. A splined input shaft extending from the motor vehicle transmission mates with the inside diameter of a splined trunnion on the interaxle differential housing to provide input torque. The interior of the interaxle differential housing includes four (4) substantially flat thrust surfaces for support of left and right side gears and first and second pinion mate gears. The first pinion mate gear and the second pinion mate gear are retained in the interaxle differential housing by stub shafts which are threaded into the interaxle differential housing wall. The stub shaft design includes a shoulder to provide controlled perpendicularity and torque retention and a recessed socket head to facilitate installation. A housing endcap is utilized for sealing and supporting the interaxle differential housing bearing and the input shaft.

Abstract: Various embodiments of a saddle type vehicle are described. Configurations are shown in which the engine is located more towards the rear of the vehicle and in which the fuel tank extends generally vertically beneath the steering member. A radiator may also be located at a rear portion of the vehicle, rearwardly of the engine. A front storage compartment is also provided in the front portion of the vehicle. The resulting vehicle has improved access and storage capabilities and also has a lower center of gravity.

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 selectively generates a control signal which controls the amount of torque provided to driveshafts 22, 26. Controller 40 provides an improved torque adjustment “response” by automatically adjusting to the condition of the vehicle's tires.

Abstract: A front and rear wheel drive vehicle 1 having a front wheel pair 7, 7 and a rear wheel pair 11, 11, one of which is driven with an engine 2 and the other one of which is driven with an motor 3, comprising: a target engine driving force setting means (an engine driving force setting section 12c) for obtaining a target driving force of the engine based on driving conditions of the vehicle; a target motor driving force setting means (a motor driving force setting section 12d) for obtaining a target driving force of the motor based on driving conditions of the vehicle; and a control means (a control section 12a) for controlling the driving force of the motor by way of modifying a change amount of a motor driving force command value associated with a change amount of the target motor driving force obtained by said target motor driving force setting means in accordance with an instance where the target driving force of the engine and the target driving force of the motor are both increasing or decreasing to thereby

Abstract: An apparatus for controlling a drive force produced between a road surface and each of two drive wheels of a motor vehicle having a differential disposed between the drive wheels and a drive power source and connecting the drive wheels in a differential manner, and two brakes for braking the respective drive wheels, independently of each other, the apparatus including two wheel speed sensors for detecting the speeds of the respective drive wheels, and a brake control device responsive to the outputs of the sensors, for activating one of the two brakes which corresponds to one of the drive wheels which has a smaller critical value of the drive force with respect to the road surface, to thereby apply a braking torque to the one drive wheel for increasing an apparent value of the drive force of that one drive wheel, in order to increase the actual value of the drive force of the other drive wheel which has a larger critical value of the drive force.

Abstract: A driving apparatus is used in a vehicle wherein both the front and rear wheels are driven. The apparatus prevents the steerable wheels from skidding while transmitting power to the steerable wheels when turning the vehicle. The apparatus includes a transmission unit 13 for receiving a rotational output from a main HST 50, a steerable wheel drive shaft 6 and a nonsteerable wheel drive shaft 5 for receiving the rotational output from the transmission unit and delivering the output respectively to an axle for driving the steerable wheels and an axle for driving the nonsteerable wheels, and a differential unit for rotating the drive shaft 6 at an increased speed and the drive shaft 5 at a decreased speed.

Abstract: A straddle-type vehicle has configurations in which the engine is located more towards the rear of the vehicle and the fuel tank extends generally vertically beneath the steering member. A radiator may also be located at a rear portion of the vehicle, rearwardly of the engine. A front storage compartment s also provided in the front portion of the vehicle. The resulting vehicle has improved access and storage capabilities and also has a lower center of gravity. The engine may be a four stroke engine, which is more environmentally friendly than a two stroke engine. Because of the increased space requirements of a four stroke engine, a secondary portion of the engine is provided forward of the seat to define an uppermost portion that defines a bottom portion of an access area that the user uses to mount and dismount the vehicle.

Abstract: A forward and aft torque distribution system and a method of controlling forward and aft torque distribution for a four-wheel vehicle having an electronically controlled clutch to control split of drive torque to be transferred to front and rear wheels are disclosed. A 4WD controller is responsive to mode selection signals from a mode changeover switch and a vehicle speed signal delivered from a vehicle speed sensor, and has control modes involving at least a LOCK mode and an AUTO mode. When the vehicle speed becomes less than a vehicle's halt discriminative vehicle speed indicative of a vehicle's halt state during the LOCK mode, the controller allows the electronically controlled clutch to be released.

Abstract: A power transmission apparatus has a transmission mechanism (3) having an input shaft (19), speed changing units (7) and (9) disposed coaxially therewith, and a power distribution apparatus (5) linked to sub-shaft (31) via a power transmission mechanism (47) disposed in parallel with the sub-shaft (31), which transmits input rotation from output shafts (41, 43) to front and rear wheels.

Abstract: A method is provided for determining an acceptable torque level to be applied to at least one clutch pack (of an automobile) which includes the requirement of internal slip to transmit torque. The automobile includes a plurality of wheels. A velocity is sensed at each of the plurality of wheels of the automobile. A speed information value is calculated. The speed information value is a function of the sensed velocities at each of the plurality of wheels. The speed information value is then compared with a calibration table. Finally, the acceptable torque level is determined primarily from the calibration table based on the speed information value.

Abstract: A powertrain assembly includes a first housing defining a first longitudinal axis. The first housing also has an axially extending pilot. The powertrain assembly further includes a second housing defining a second longitudinal axis and an outer wall. The outer wall has a guide face formed on an inner surface. The pilot is disposed within the second housing and engages the guide face to align the first and second longitudinal axes. A fastener interconnects the second housing on the first housing.

Abstract: A motor vehicle torque transfer case pump drive which is mounted in the front of a torque transfer case where it mounts to a motor vehicle transmission and includes a drive arrangement, such as a chain drive, a belt drive or a gear drive. This permits an auxiliary hydraulic pump to be driven directly from the torque transfer case, thus eliminating the need for a power take-off (PTO) adapter to drive the auxiliary hydraulic pump.

Abstract: To provide a four-wheel vehicle for traveling on an irregular road superior in weight balance and traveling stability. A center line (L3) of a rotational axis of a torque converter and a longitudinal center line (L2) of a drive shaft or a propeller shaft, which transmits a driving force from a transmission mechanism M to front or rear wheels, are distributed right and left in an opposed relation to each other with respect to a longitudinal center line (L1) of a vehicle body.

Abstract: A drive-force distribution controller for a four-wheel-drive vehicle which provides a torque distribution unit distributing an output torque transmitted from a prime motor to driving wheels to driven wheels, is composed of a wheel speed sensor for detecting a wheel speed in each of the driving and driven wheels; a first judging means for judging which of the driven wheel is an inner wheel based upon the detected wheel speeds; a second judging means for judging that the inner wheel of the driving wheels slips when the detected inner wheel speed of the driving wheel is larger than the detected outer wheel speed thereof; a third judging means for judging whether a slip of the outer driving wheel happens or not by comparing the detected wheel speed of the outer driving wheel with a calculated wheel speed thereof based upon the detected wheel speeds of the inner driving wheel and driven wheels; and a transmissible torque control means for controlling the torque distribution unit so as to increase the output torque

Abstract: A system and method are provided for detecting faults in an encoder used for position feedback as part of a transfer case in an electronic-shift 4×4 vehicle. Encoder signal failures including open-circuit, short-to-ground, and short-to-power faults and encoder power line failure with open-circuit or short-to-ground fault are detected. The methodology ensures that no fault is set due to transients seen immediately after the power-set up in the system or after turning a relay off at the end of a shift. If the relays are off and an intermittent physical fault changes the encoder code, the fault flag is reset by the methodology when the fault disappears. The physical encoder faults which are transparent from the encoder code in stationary motor are detected by an intelligent recursive index-based algorithm which works when a shift is commanded.

Abstract: There is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the execution and cancellation of a lock mode in which the engagement forces of clutches for distributing a driving force to auxiliary drive wheels are made maximum, thereby reducing frequency and duration of the lock mode. Further, there is disclosed a driving force control system for a four-wheel drive vehicle, which is capable of properly controlling the engagement forces of clutches for distributing a driving force of the main drive wheels to auxiliary drive wheels, thereby causing the clutches to efficiently operate without waste of power.

Abstract: An all-terrain vehicle has a selectively engageable four wheel drive system. The system has dedicated rear wheel drive and selectively engageable front wheel drive. The front wheel drive is engaged within the differential housing. A differential input shaft extends into the differential housing. A stub shaft is journaled for rotation within the housing. A sleeve slides relative to the two shafts and couples the two through a coupling configuration. The coupling configuration results from the externally splined ends of the two shafts and the internally splined surface of the sleeve. The positioning of the sleeve is controlled by a shift fork. The shift fork is moved by an actuator in response to a signal produced by a control unit. A switch allows an operator to instruct the control unit when to engage and disengage the front wheel drive system.

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 motor vehicle power train includes an engine (26) mounted longitudinally in the vehicle adjacent one end, a change speed transmission (28) spaced from and drivably connected to the engine through an input propshaft (31) and a transfer transmission (29) mounted on the change speed transmission and drivably connected to a front differential through a front propshaft (34) and to a rear differential through a rear propshaft (35). The change speed transmission has an input shaft (39) to receive drive at one end from the engine and an output shaft (41) axially offset from the input shaft and having a drive output at the opposite end. The transfer transmission is arranged at the opposite end of the change speed transmission and includes a center differential (56) having differential output shafts (57, 58) drivably connected to the front and rear propshafts and axially offset from the input shaft and the change speed transmission output shaft.

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 hydraulic coupling device includes left and right vane pumps which discharge working oil in response to the relative rotation of main driven wheels and left and right subsidiary driven wheels. First orifices are defined in a side plate disposed between the left and right vane pumps to permit communication between intake ports and discharge ports in the vane pumps. Orifices are defined in the side plate to permit communication between the intake ports and between the discharge ports in the vane pumps. With the above arrangement, in a hydraulic coupling device of a power transmitting system in a four-wheel drive vehicle, the formation of the orifices can be easily carried out, and the characteristics of the orifices can be stabilized.

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: An all wheel drive system for a motor vehicle comprising a front differential, a pair of front halfshaft assemblies operatively connected to the front differential whereby the front differential supplies torque to the pair of front half shaft assemblies, each of the pair of front half shaft assemblies connected to a respective front wheel, a power takeoff unit operatively connected to the front differential, a constant velocity joint connected to the power takeoff unit whereby the front differential supplies torque to the constant velocity joint through the power takeoff unit, a first propshaft having a first end and a second end, the first end connected to the constant velocity joint, a plunging constant velocity joint connected to the second end of the first propshaft, a second propshaft having a first end and a second end, the first end connected to the plunging constant velocity joint, a universal joint having a first end and a second end, the first end of the universal joint connected to the second end o

Abstract: In the case that a brake controller is installed to a 4 wheel driven vehicle, braking force control should be carried out effectively enough so that running stability of the vehicle can be up-graded at cornering. The brake controller 40 calculates differential value of aimed yaw rate, differential value of predicted yaw rate on low friction road and deflection of the two differential values. And also it calculates deflection of real yaw rate and aimed yaw rate. Then the brake controller 40 determines aimed braking force and applies the aimed braking force to a selected wheel to carry out braking control. The torque distribution controller 70 receives control parameters and signals of status of brake control and carries out torque distribution control based on the parameters and signals through the hydraulic multi-plate clutch 21.

Abstract: A four-wheel driven wheel has a rear-wheel driving system branching at the intermediate thereof into a front-wheel driving system comprising a first transmission for driving the front wheels at a peripheral speed substantially identical with that of the rear wheels and a second transmission for driving the front wheels at a peripheral speed higher than that of the rear wheels. A hydraulic clutch device is provided, including a hydraulically operable first friction clutch for connecting and separating the first transmission with the rear-wheel driving system, a hydraulically double-acting first piston for engagement and disengagement of the first friction clutch, a first fluid chamber for the clutch-engaging action provided at one side the first friction clutch, a second fluid chamber for the clutch-disengaging action provided at the other side thereof, and a biasing member for biasing the first friction clutch to engage disposed in the first chamber.

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: A four-wheel hydraulic drive system for a working vehicle comprising a hydraulic pump, a first hydraulic motor fluidly connected with said hydraulic pump, a pair of first driving wheels driven by said first hydraulic motor, a second hydraulic motor fluidly connected with said hydraulic pump, and a pair of second driving wheels driven by said second hydraulic motor, wherein the drive mode of said vehicle can be switched between a first four-wheel drive mode for substantially equaling the torque of said second hydraulic motor to that of said first hydraulic motor and a second four-wheel drive mode for making the torque of said second hydraulic motor smaller than that of first hydraulic motor.

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 four-wheel drive vehicle of the present invention includes: a first differential mechanism for distributing engine drive force to front drive wheels and rear drive wheels; a second differential mechanism for distributing engine drive force to left and right main drive wheels (the main drive wheels get more drive force than other drive wheels); first differential-limiting device for operating differential-limiting control by the first differential mechanism; second differential-limiting device for operating differential-limiting control by the second differential mechanism; rotational speed detection device for detecting rotational speed of each drive wheel; turn direction detection device for detecting the direction of a turn that the vehicle is making; and control means for, based on detection signals from the rotational speed detection device and the turn direction detection device, controlling differential-limiting force provided by the second differential-limiting device according to a difference betwee

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 44 is connected, through a main transmission 42, to an engine 40 disposed in a front side of a vehicle, and a propeller shaft 52 is connected between the transfer 44 and a rear differential device 54 in a longitudinal direction of the vehicle. An input gear 52a formed on one end of the propeller shaft is meshed with a rear wheel output gear 44a at the side of the transfer which transmits a driving torque of the engine to the side of the rear wheels. An output gear 52b formed on the other end of the propeller shaft is meshed with a rear differential gear 54a of the rear differential device. The number of teeth of the input gear 52a of the propeller shaft and the number of teeth of the output gear 52b of the propeller shaft are set different from each other.

Abstract: A four-wheel drive vehicle includes a first transmission system for transmitting power from an engine to a left and a right first driving wheel provided with a braking unit, and a second transmission system branching off from the first transmission system to transmit power to a second pair of driving wheels serving as steerable wheels. The second transmission system is provided therein with a frictional transmission passage having a frictional torque, which is smaller than that between the second driving wheels and a road surface, and a direct transmission passage disposed in parallel with the frictional transmission passage, so that either passage can be selected. The frictional transmission passage is selected when a speed-changing operating tool is set to its high speed position or when a steering device is operated beyond a predetermined angle, and the direct transmission passage is selected in all other cases.

Abstract: A method for controlling a transfer case in a four wheel drive vehicle is provided. The transfer case has a neutral state and a plurality of drive modes. A MSS having a plurality of positions is provided for selecting the drive modes. An upshift relay and a downshift relay energize a motor to effect a shift of the transfer case to the selected drive mode. An encoder detects a value corresponding to the rotational position of the motor. The method senses if the encoder has lost power, and upon sensing the encoder has lost power, compares a current MSS position with a MSS position prior to losing power to the encoder. If the current and prior MSS positions differ, the most recent valid MSS position is determined. Whether the upshift and downshift relays are turned "on" is established. The direction of rotation of the motor is established. The desired motor destination is established.

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: In a four-wheel drive vehicle, a rear differential includes an input shaft to which a driving force is transmitted from front wheels through a propeller shaft, a driven bevel gear mounted on the input shaft, a follower bevel gear mounted on a clutch drive shaft and meshed with the driven bevel gear, left and right electromagnetic clutches disposed between opposite ends of the clutch drive shaft and left and right output shafts. The maximum transmitted torque transmitted through the left and right electromagnetic clutches is controlled, so that it is decreased with an increase in vehicle speed detected by vehicle speed detecting means. Thus, the vehicle can avoid the maximum horsepower transmitted by the bevel gears and the electromagnetic clutches being increased with an increase in vehicle speed. Therefore, it is possible to ensure the durability of the bevel gears and the clutches, while providing a reduction in size of the bevel gears and the clutches.

Abstract: This is a connecting device (7) to be interposed between left and right wheels (5L, 5R) of a vehicle. It enables to perform a starting assistance control, a cornering control to improve the cornering performance by positively generating a difference rotation between left and right wheels, and a differential limiting control for restricting the difference rotation between the left and right wheels. There are provided: a differential gear (8) having a first rotational element (8a), and second and third rotational elements (8b, 8c) so arranged that, when one of them rotates in the forward direction relative to the first rotational element (8a), the other thereof rotates in the reverse direction; and a driving source (9) connected to the first rotational element (8a). One of the second and third rotational elements, e.g.

Abstract: In a coupling device which is disposed between left and right wheels of a vehicle, pair of differential gears are provided. First rotational elements of both the differential gears are coupled to each other, and second rotational elements are respectively coupled to left and right wheels of the vehicle. A third rotational element of one of the differential gears is driven for rotation by a driving source. The third rotational element of the other of the differential gears is made switchable by a switching device between a state in which the third rotational element is prevented from rotating and a state in which the third rotational element is coupled to the first rotational element or the second rotational element of the other of the differential gears. Otherwise, the third rotational element of the other of the differential gears may be arranged to be always prevented from rotating.

Abstract: A rear differential in a four-wheel drive vehicle includes a left and right clutches adapted to distribute a driving force transmitted from front wheels through a propeller shaft to left and right rear wheels. If the engagement of the left and right clutches is released, only the front wheels are driven and in this manner, the vehicle is brought into a front wheel-drive state. If the left and right clutches are brought into their engaged states, both of the front wheels and the rear wheels are driven and in this manner, the vehicle is brought into a four-wheel drive state. By changing the engagement forces of the left and right clutches, different driving forces can be distributed to the left and right rear wheels. In addition, when a driver operates a differential lock switch, the left and right clutches, are brought into their engaged states with the maximum engagement force, thereby integrally coupling the propeller shaft to the left and right rear wheels to provide a differential-locked state.

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: A process for controlling a yaw moment in a vehicle by generating a braking force in one of the left and right wheels of the vehicle and by generating a driving force in the other wheel. When a vehicle is accelerated during the turning thereof, grounding loads of rear wheels are increased in order to generate a yaw moment in a direction opposite from a turning direction. However, such yaw moment can be eliminated in order to enhance the turning performance by bringing one of the hydraulic clutches into an engaged state with a torque which is proportional to a product of longitudinal and lateral accelerations. Consequently, a braking force and a driving force in inner and outer wheels during turning of the vehicle, respectively, are generated. When the vehicle is decelerated during turning thereof, grounding loads of front wheels are increased to a yaw moment in the same direction as the turning direction.

Abstract: An on demand venicle 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 driving torque control apparatus has a first differential restraining device which restrains a rotational speed differential between front-left and front-right wheels by adjusting driving torque to be transmitted from a power source mounted on a four-wheel drive vehicle to each of the front-left and front-right wheels, and a second differential restraining device which restrains a rotational speed differential between rear-left and rear-right wheels by adjusting driving torque to be transmitted from the power source to each of the rear-left and rear-right wheels. An adjustment of driving torque by the second differential restraining device is executed in preference to an adjustment of driving torque by the first differential restraining device.

Abstract: A method of monitoring the relative effective diameters of the tires and compensating therefor 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, each of the wheels having an effective diameter. Front and rear driveshaft values indicative of the rotational speed of each driveshaft are generated. A difference value indicative of a difference between said front and rear driveshaft values is then generated. A low pass filtered value is generated according to the relationship of Y.sub.1p =(1-.beta.)*U(k)+.beta.*Y.sub.1p (k-1). The low pass filtered value is monitored for a predetermined period of time to determine if one of the wheels has a smaller effective diameter than the other wheels.

Abstract: An all wheel drive transmission has a transfer gearing apparatus disposed in axial alignment between a hydrodynamic input drive and an input member of a planetary transmission. The transfer gearing apparatus delivers power from the hydrodynamic drive to the planetary transmission and from a differential output of the planetary transmission to a first output drive member. A second output drive member is connected to the differential output. One output drive member is connectable with the front drive wheels of a vehicle and the other output drive member is connected with the rear drive wheels of the vehicle.

Abstract: A motor vehicle power train includes an engine (26) mounted longitudinally near the front of the vehicle and a transmission assembly (35) mounted intermediate front and rear differentials (17, 18). The transmission assembly is connected to the engine through an input propshaft (31), to the front differential through a front propshaft (37) and to the rear differential through a rear propshaft (38). The transmission assembly comprises a change speed transmission (28) which receives drive from the input propshaft and a hollow output shaft (49), a transfer transmission comprising a center differential (30) which is drivably connected to the hollow output shaft, has a front differential output shaft (54) for transmitting drive to the front propshaft and a rear differential output shaft (56) for transmitting drive to the rear propshaft, one of the differential output shafts (54) extending co-axially through the hollow output 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: In control apparatus and method for a four-wheel drive vehicle, when the vehicle in which two tire wheels having different radii from those of originally equipped tire wheels are mounted as either front tire wheels or rear tire wheels is running at a speed exceeding a reference speed (approximately, 40 km/h), a rate of distribution of an engine driving force between mainly driven tire wheels and auxiliarily driven tire wheels set on the basis of a rotation speed difference between the mainly and auxiliarily driven tire wheels (.DELTA.V.sub.W) is modified so that the driving force distributed to the auxiliarily driven tire wheels can be maintained constantly at its minimum limit so as to prevent a control hunting of the driving force distribution to the auxiliarily driven tire wheels based on the rotation speed difference from occurring.

Abstract: A drive mechanism for 4WD automobiles is disclosed. In the drive mechanism, the center differential (C/D) unit, used for distributing the drive power of an engine to front and rear wheels, is an epicyclic gear train. The C/D unit is operated by a differential drive (D/D) gear. The front differential (F/D) unit, used for transmitting the drive power from the C/D unit to the front wheels, is a bevel gear train. The viscous coupling is connected to the C/D unit, thus limiting the differential operation of the C/D unit. The middle shaft is positioned at a side of the transmission and is rotated by the C/D unit. The middle shaft has a spiral bevel gear for transmitting the drive power to the rear wheels. Due to such a middle shaft, the transfer case is easily installed without causing any interference between the transfer case and the cylinder block of an engine.

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.