Abstract: A power transmission changeover device for an automatic-transmission, four-wheel drive vehicle which can prevent rattling of gears while the gear position of the sub-transmission is being changed over. Air pipes extending from a negative pressure source for actuating an actuator for changing over gears of a sub-transmission, and electromagnetic valves have inner diameters of 4 mm or over. An accumulator is provided between the electromagnetic valves in the air pipes and the negative pressure source. This makes it possible to increase the operating speed and operating force of the actuator and, to shorten the duration of the neutral position when gears are changed over, and to increase the meshing force with new gears. It is thus possible to prevent rattling of gears due to improper meshing of gears.

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 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: A two/four wheel drive shifting device capable of detecting a success or failure in shifting of a free wheel mechanism to a locked state without encumbering components for detecting free and locked states of the free wheel mechanism being directly disposed in the free wheel mechanism. The two/four wheel drive shifting device has a two/four wheel drive shifting mechanism disposed in a transfer mechanism, a device for detecting shifting between two wheel and four wheel drive, an indicator for showing the shifting, an actuator for shifting a free wheel mechanism which is disposed in either a front wheel or a rear wheel differential mechanism, a pressure pump for supplying working pressure, a pressure detector for detecting the working pressure, and a control to actuate the pressure pump to supply working pressure to the actuator when shifting to four wheel drive is successful.

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: An automatic transmission and transfer case operatively mounted in a four wheel drive vehicle controlled by a single selector lever that is moved to predetermined detented positions along a longitudinal gate to select the transmission drive ranges, reverse, neutral and park. A special pivot construction allows the selector lever to be moved laterally with respect to the normal longitudinal movement for transfer case gear ratio changes and neutral selection. A small lateral gate is employed to receive the selector lever located in alignment with the neutral detent position of the automatic transmission requiring the transmission to be in neutral when the transfer case is shifted. When moved into the lateral gate, the selector lever activates electronic controls effecting operation of a motor for shifting transfer case gear ratios and for selecting transfer case neutral.

Abstract: A transmission is provided for a tractor having a rear permanently engaged drive axle and a front selectively engaged drive axle and includes a coupling for selectively applying torque to the front drive axle of the vehicle to switch between two wheel drive and four-wheel drive in dependence upon slipping of the wheels of the rear axle. The coupling includes first and second gears, arranged to rotate with the rear and front axles, respectively, and having teeth which mesh with one another, and a rotary fluid valve sensitive to the rear wheel slip dependent relative angular position of the first and second members for actuating a jacking device that is operative to enable and disable the transmission of drive torque through the coupling to the front axle.

Abstract: A vehicle transfer case for movement between two- and four-wheel drive includes a stop cushion as an end of travel range is approached. The cushion is preferably provided by a generally U-shaped spring that is contacted by the stop at either of its ends of travel. The cushion prevents the stop from locking into a housing for the gear.

Abstract: A method of controlling the amount of power delivered to the front driveshaft and to the rear driveshaft of a motor vehicle including the steps of generating a front driveshaft value indicative of the rotational speed of said front driveshaft and generating a rear driveshaft value indicative of the rotational speed of said rear driveshaft. A vehicle speed is generated based on the lower of said front driveshaft value and said rear driveshaft value. The amount of power delivered to said front driveshaft and to said rear driveshaft is controlled as a function of said vehicle speed.

Abstract: A four-wheel drive control system for an automotive vehicle equipped with a transfer including a friction clutch for distributing a driving force to rear wheels and front wheels under a control of an engaging force of the friction clutch.

Abstract: A power transfer arrangement has a transmission mounted on a prime mover of a machine and at a predetermined angle "b" relative to an elevational plane of a longitudinal machine axis. The prime mover is at a predetermined angle "a" relative to the longitudinal machine axis. A first drive shaft is connected to deliver rotary power between first and second spaced differentials mounted on and beneath a frame of the machine. A second drive shaft, at a predetermined angle "c" relative to the longitudinal centerline of the prime mover and at a predetermined angle "d" relative to the longitudinal machine axis, is connected to deliver rotary power between the prime mover and the differentials. The first and second drive shafts are elevationally beneath the frame and substantially in a transverse plane of the longitudinal machine axis. A transfer gear case of the second differential transfers rotary power from the second drive shaft to the first drive shaft.

Abstract: A drive train assembly and monitoring system for indicating the operating condition of the drive train assembly includes a drive train assembly having a power distribution device for distributing rotative power within the drive train. A sensor is attached to a portion of the drive train assembly, the sensor being responsive to the vibration of the portion or component of the drive train assembly for generating signals indicative of the sensed vibration. A controller receives the signals from the sensor and generates an indication of the operating condition of the drive train assembly based on the vibration of the portion of the drive train assembly. Preferably the sensor is adapted to detect both the frequency and magnitude of vibration of the drive train assembly and to generate signals indicative of the sensed frequency and magnitude of vibration.

Abstract: A transfer system for a four-wheel drive vehicle comprising: a transfer case for transferring driving modes; a transfer-operating part for activating and controlling said transfer; a button shifting assembly for selecting driving mode; a speed sensor for detecting a vehicle speed; a neutral switch which switches on when a transmission mode is neutral; and an electronic control unit which controls the transfer-operating part regarding the vehicle speed, the transmission mode sensor and the button shifting assembly.

Abstract: A driving-torque control system for a four-wheel-drive vehicle includes a transfer clutch employed in a transfer of the four-wheel-drive vehicle for varying a distribution ratio of driving torque between front and rear road wheels depending on a front-and-rear wheel revolution-speed difference. A calculation unit derives a command value of the engaging force of the transfer clutch from the front-and-rear wheel revolution-speed difference. A load-condition detection unit detects an input load condition of the transfer clutch, on the basis of the front-and-rear wheel revolution-speed difference and the command value of the engaging force. A comparing unit compares the input load condition detected by the load-condition detection unit with a predetermined threshold. A compensation unit compensates the engaging force of the transfer clutch so that the transfer clutch is held in a completely engaged state for a predetermined holding time duration, when the input load condition exceeds the predetermined threshold.

Abstract: A system for controlling a four-wheel drive for a motor vehicle comprises a drive mode switch for detecting a drive mode of the motor vehicle selectable between a two-wheel drive mode and a four-wheel drive mode. The four-wheel drive mode is selectable between a direct-coupled four-wheel drive mode. A an auto four-wheel drive mode, a controller controls the distribution of traction between main and secondary driving wheels. A traction transmission train distributes traction between the main and secondary driving wheels. The traction transmission train has an oil pressure supply system having a friction clutch and a solenoid.

Abstract: An integrated wheel end for a vehicle is disclosed. The integrated wheel end has a hub rotatably mounted to a bearing pack. The integrated wheel end is secured to the vehicle by fastening the bearing pack to a knuckle of the vehicle. The integral hub has a spindle portion for receiving an end portion of a drive axle, a clutch housing for receiving a locking clutch mechanism and a flange for the mounting of a brake rotor and a vehicle supporting wheel. A locking hub clutch is mounted in the clutch housing and is selectively operated to provide unity of rotation between the axle and the hub or to provide independent rotation of the axle and the hub. The clutch housing is suited for installing different clutch mechanisms including manually operated and pressure operated either by negative or positive pressure. The integrated wheel end has a sealed defined cavity and an air circuit for the introduction or withdrawal of air to operated the pressure operated clutch mechanisms.

Abstract: A four-wheel drive vehicle includes a transfer case for controlling the delivery of power between the front and rear wheels of the vehicle. A clutch in the transfer case controls the amount of power delivered to the front and rear wheels in response to a clutch PulseWidth Modulated (PWM) signal which is generated by an electronic powertrain controller. The powertrain controller receives a first signal which is indicative of the rotational speed of a front driveshaft, which transfers motive power from the transfer case to a pair of front wheels, and a second signal which is indicative of the rotational speed of a rear driveshaft, which transfers motive power from the transfer case to a pair of rear wheels.

Abstract: A system for detecting an operating state of an automobile free-wheel hub mechanism used for connecting and disconnecting a driveshaft to and from a wheel hub by engaging and disengaging a fixed gear firmly connected to the driveshaft for rotation with the driveshaft with and from a movable gear slidably splined to the inner periphery of a cylindrical housing of the wheel hub, comprises sensors for detecting a revolution speed of a road wheel having the wheel hub to generate a wheel-speed indicative signal, another sensors for detecting a revolution speed of the driveshaft to generate a driveshaft revolution-speed indicative signal, and a controller for detecting an operating state of the free-wheel hub mechanism on the basis of a deviation between a value of the wheel-speed indicative signal and a value of the driveshaft revolution-speed indicative signal.

Abstract: A control system for engaging, disengaging and re-engaging a front wheel drive in an agricultural vehicle includes a control circuit configured to receive signals representative of vehicle operating parameters and to generate control signals corresponding to the desired state (i.e. engaged or disengaged) of a front wheel drive engagement circuit. Sensors are associated with the rear wheels, rear service brakes, implement positioning circuit, the vehicle body and the front axle to provide parameter signals related to wheel speed, braking, implement position and vehicle speed. Control logic executed by the control circuit in a continuously cycled routine determines the desired state of the engagement circuit based upon all operating parameters. The control circuit applies an appropriate control signal to the engagement circuit causing engagement or disengagement in accordance with the desired state.

Abstract: In a driving force transfer apparatus for a part-time four-wheel drive vehicle with a fail safe structure, a high-speed gear range shift position and a low-speed gear range shift position in a high-speed and low-speed gear range position switching mechanism in a sub transmission are determined without special position sensors. In a case where the special position sensors are installed in the transfer apparatus, a shift position sensor diagnosis operation is effected so that a failure in either of a high-speed gear range position or low-speed gear range position sensor can easily be detected. If the failure in either of the position sensor occurs, a hydraulic (oil) pressure supply for providing a clutch pressure for a frictional clutch is made effective. Furthermore, a failure of either of revolution speed sensor detecting a first output axle revolution speed or detecting a second output axle revolution speed can also be detected. The first output axle is connected to mainly driven road wheels.

Abstract: In a control system for distributing a driving force from an engine between the front and rear wheels of a vehicle, a controller is designed to decrease the driving force transmitted to the secondary drive wheels which may be the front wheels by modifying a driving force distribution control characteristic when the vehicle is in a predetermined constant speed steady state, in order to improve the fuel economy in the steady state operation while maintaining a vivid vehicle response to a driver's accelerator input. Preferably, the controller determines an offset quantity L which has at least a cubic term proportional to the third power of a vehicle speed when the predetermined steady state exists, and increases the driving force to the secondary wheels as an excess of the wheel speed difference over the offset quantity increases from zero.

Abstract: An improved electric shift transfer case system (10) and electronic control circuit (16) therefor utilizes a microprocessor (73), interface circuit (72), and motor drive circuit (70) to control energization of a direct current electric shift motor (58) that is used to switch between drive modes in the transfer case (14) of a full or part-time four wheel drive vehicle. The motor drive circuit (70) includes four switching elements, such as transistors (74-77). The first and second switching elements connect respective first and second ones of the two motor terminals (58a,58b) to a supply voltage and the third and fourth switching elements connect the first and second motor terminals (58a,58b), respectively, to ground. The switching elements (74-77) each have a conductive state and non-conductive state selectable by a command input that is coupled to and controlled by data outputs of the microprocessor (73).

Abstract: A crank shaft of a power unit is disposed in the longitudinal direction of a vehicular body. Accessories provided at either end portion of the crank shaft are covered with a front cover and rear covers which are removable from a casing. Front and rear drive shafts are disposed to be lower than the axial line of the crank shaft. A fan unit and an air cleaner are disposed to be higher than the axial line, so that front and rear operating spaces for inserting an impact wrench are formed in front of and in back of the front cover and the rear covers. The maintenance is performed through the operational spaces.

Abstract: A cross-country vehicle comprising an all-wheel drive is driven by a reciprocating engine installed transversely close to the front axle and by means of a change speed transmission which is also disposed transversely in the front. From the change speed transmission, the drive torque flows onto a planetary transmission operating as a center differential. The ring gear of the planetary transmission drives the front axle; the sun gear drives a low-high change-over unit. The planetary transmission, the change-over unit and the wheel sets connected behind it are constructed such that, during the high operation, the major portion of the torque is available at the front axle, and, in the low operation, is available on the rear axle. The center differential can be locked in the high and in the low operation.

Abstract: An improved automobile transfer case system (10) and electronic control circuit (16) therefor utilizes a reset circuit (70), a microprocessor (72), and an output stage (74) to operate an electronically controlled coupling (38,58) that is used to switch between drive modes in the transfer case (14) of a full or part-time four wheel drive vehicle. The microprocessor (72) is connected to a source of operating power that is available even when the vehicle ignition is switched off. The microprocessor (72) runs in two modes, a low power standby mode and an operating mode. The microprocessor enters the standby mode when vehicle ignition is switched off and it has finished any tasks that were in progress when the ignition was turned off. The reset circuit (70) responds to the ignition being switched on to provide a hardware reset of the microprocessor (72) that wakes it up from its standby mode and places it into the operating mode.

Abstract: A transfer case (10) having a drive shaft (12) on a bearing (18) to permit the drive shaft to be rotated with respect to the transfer case, the drive shaft having a free end portion (12a) which is adapted to drive an axle of a vehicle. The drive shaft passes through a sleeve (20), and bearings (22, 24) are provided to permit the sleeve to be rotated with respect to the transfer case. The sleeve has a sprocket (14) affixed to it, and the sprocket is caused to rotate by an endless chain (16). The sleeve is drivingly connected to the drive shaft by a universal joint (26), preferably a cardan joint, which is contained within an enlarged end portion (20a) of the sleeve. The sprocket is positioned between the universal joint and the free end portion of the drive shaft, to maximize the distance therebetween, and thereby minimize the included angle required of the universal joint.

Abstract: A method of controlling the driving state of a vehicle in which an antilock brake control for eliminating a locking tendency of a wheel during braking can be carried out, and a four-wheel drive state and a two-wheel drive state can be switched from one to another. A monitored estimated vehicle speed is calculated on the basis of highest one of wheel speeds of the vehicle wheels and a value is detected by a longitudinal acceleration/deceleration sensor for detecting a longitudinal acceleration or deceleration of a vehicle speed, and a judgement speed is determined at a value lower than the monitored estimated vehicle speed. The vehicle speed is also independently determined based upon the speed of each of the vehicle wheels. The four-wheel drive state is switched to the two-wheel drive state in response to highest one of vehicle speeds independently calculated on the basis of the wheel speeds becoming equal to or less than the judgement speed in the four-wheel drive state.

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 drive shafts, differentials and 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 comprising a primary, cone clutch assembly which functions as a pilot device to actuate a secondary, disc pack clutch assembly. The electromagnetic clutch is 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 shaft overruns, i.e.

Abstract: A transfer case includes a clutch assembly having a disc pack clutch, a cone clutch and a lockup hub or collar. All three clutch components are disposed in mechanical parallel between the primary transfer case shaft and the secondary output. The disc pack clutch includes a plurality of interleaved discs and an electromagnetic operator which effects compression of the disc pack to transfer torque from the primary transfer case output shaft to a chain drive sprocket, through a chain, to a secondary output shaft. The cone clutch is disposed adjacent the disc pack and is also actuated by the electromagnetic operator. The cone clutch includes a conical drive member driven by the primary transfer case output shaft. A conical driven member provides torque to the drive chain and, in turn, to the secondary output shaft. Preferably, the driven cone member is integrally formed with the chain drive sprocket.

Abstract: The present invention is directed to a power transfer system of the type having a transfer case incorporated into the driveline of a full-time four-wheel drive vehicle. The transfer case includes an inter-axle differential for normally delivering drive torque to all four wheels so as to establish a full-time drive mode of operation. In addition, the transfer mechanism is equipped with a clutch assembly for controlling speed differentiation across the inter-axle differential and selectively varying the distribution ratio of the drive torque transmitted to the front and rear wheels. The transfer mechanism is also equipped with a rotary actuator and a drive mechanism for actuating the clutch assembly. The power transfer system further includes sensors for detecting various dynamic and operational characteristics of the vehicle and generating sensor input signals indicative thereof. A controller is provided for processing the input signals and controlling actuation of the rotary actuator in response thereto.

Abstract: The present invention is directed to an electronic clutch control mechanism for use in a vehicle transmission such as a four wheel drive transfer case 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.

Abstract: A 4-wheel tractor having brakes on the rear wheels only and an FWD clutch for selectively drivingly coupling the front wheels to the rear wheels, is provided with a control circuit, operative during rear wheel braking, for controlling the clutch so that the front wheels are intermittently coupled to and uncoupled from the rear wheels. Brake pedals which individually control the rear wheel brakes, and a hand brake all control switches connected to a controller. An FWD switch is also connected to the controller. A ground speed sensor applies to the controller a signal representing the speed of the tractor. If the tractor speed is above 15 mph at the time both brake pedals are depressed, the controller selectively controls a solenoid so that the clutch is selectively engaged and disengaged in a first sequence if the FWD switch is ON but selectively controls the solenoid so that the clutch is selectively engaged and disengaged in a second sequence if the FWD switch is in an OFF or an AUTO position.

Abstract: A casing of a power unit is formed which is capable of simultaneously driving the front and the rear wheels of a saddle type vehicle. The power unit includes an engine and a transmission in a compact construction. A crankshaft, a main shaft, a secondary shaft and an output shaft are supported in parallel to the longitudinal axis of the vehicle in a casing for both an engine and a transmission. The crankshaft, the main shaft and the secondary shaft are arranged on substantially the same level. The output shaft is disposed below the main shaft and the secondary shaft. The opposite ends of the output shaft project outside from the casing. The opposite ends of the output shaft are connected to a front driving shaft and a rear driving shaft, respectively.

Abstract: In a power transmitting system for distributing a torque to left and right driving wheels in a front engine and front drive vehicle, a transmission is connected to one end of an engine which is horizontally disposed at a front portion of a vehicle body, and a planetary gear type differential is disposed in a space provided in the rear of the transmission. A first clutch and a second clutch are disposed laterally side by side in a space provided in the rear of the engine for controlling the torque transmitted to left and right front wheels by increasing and transmitting the rotation of a ring gear, which is an input member of the differential, to a left axle or a right axle. Thus, the pair of left and right clutches, added to the differential, can be rationally disposed by effective utilization of the spaces.

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 drive shafts, differentials and 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 comprising a primary, cone clutch assembly which functions as a pilot device to actuate a secondary, disc pack clutch assembly. The electromagnetic clutch is 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 shaft overruns, i.e.

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 method is provided for the generation of wheel acceleration control signals and wheel deceleration control signals for an anti-lock system for wheels of a vehicle. The vehicle is furnished with a digital electronic anti-lock system with at least one microprocessor. The microprocessor calculates a wheel comparison speed (v.sub.diff). The wheel comparison speed is obtained by a filtering of the actual wheel speed (v.sub.wheel), and follows in time to the actual wheel speed (v.sub.wheel). A deceleration signal (-b) or an acceleration signal (+b), respectively, is then furnished when the absolute value of the difference (.DELTA.) between the wheel comparison speed (v.sub.diff) and the actual wheel speed (v.sub.wheel) surpasses a preset value as based on the sign of the difference (.DELTA.).

Abstract: A four-wheel all terrain vehicle having a centrally-mounted engine, straddle type seating and oversized balloon tires. The vehicle is arranged such that footpegs for the rider are located inwardly of the tires to avoid interference between either the footpegs or the rider's feet and the tires. The rear tires are positioned forwardly relative to the frame such that obstacles may be encountered by the rear tires prior to the obstacle coming to beneath the center of gravity of the vehicle. The footpegs are arranged at the center of gravity and approximately half way between a ground plane and the top of the seat for clearance and rider control. The tires are spaced apart approximately the same distance as the length of the radius of the tires to improve all terrain capability and allow access to the rider position. Centers for the wheels are arranged in a substantially square configuration and the vehicle swing arms are designed to have an effective length shorter than the associated tire radius.

Abstract: A torque split control apparatus for use with 4WD type vehicle. The drive from the engine is transmitted to the primary drive wheels of the vehicle and to the secondary drive wheels of the vehicle through a torque distributing clutch capable of varying a torque transmitted to the secondary drive wheels. A wheel speed difference between speeds of rotation of the primary and secondary drive wheels, a vehicle speed and a difference between the diameters of the tires of the primary and secondary drive wheels are sensed. A dead zone is calculated as a function of tire diameter difference and vehicle speed. The calculated dead zone increases as the sensed tire diameter difference increases and as the sensed vehicle speed increases. The calculated dead zone is subtracted from the calculated wheel speed difference to correct the wheel speed difference. The corrected wheel speed difference is used to calculate a torque. A smaller one of the calculated torque and a maximum torque is selected.

Abstract: A differential action control device of a vehicle includes an inter-axle differential disposed between axles for making a differential action between the axles, an inter-wheel differential disposed between wheels for making a differential action between the wheels, and a parameter setting device for detecting a vehicle running condition and setting a predetermined parameter based on the vehicle running condition detected. The device further includes target yaw rate setting device for setting a target yaw rate of the vehicle based on the parameter, a yaw rate detecting device for detecting an actual yaw rate of the vehicle while running, and a differential control device for controlling a differential action of the inter-axle and inter-wheel differentials based on a deviation between the actual and target yaw rate of the vehicle. The steering characteristic of the vehicle can be changed to get a desirable characteristic by making the differential action control.

Abstract: A torque split control apparatus for use with an automotive vehicle including an engine for producing a drive. The automotive vehicle is supported on a pair of primary drive wheels and a pair of secondary drive wheels. The drive is transmitted from the engine to the primary drive wheels and to the secondary drive wheels through a torque distributing clutch capable of varying a torque transmitted to the secondary drive wheels. A control torque is calculated based upon a difference between the primary and secondary drive wheel rotational speeds. The control torque is transmitted through the torque distributing clutch to provide a desired turning characteristic to the vehicle. At least one vehicle condition dependent torque, which is dependent on a specified vehicle operating condition, is calculated. Vehicle operating conditions are monitored to produce a command signal when a 4WD control is demanded.

Abstract: A torque split control apparatus for use with 4WD type vehicle. The drive from the engine is transmitted to the primary drive wheels of the vehicle and to the secondary drive wheels of the vehicle through a torque distributing clutch capable of varying a torque transmitted to the secondary drive wheels. First and second control gains are calculated. The first control gain is inversely proportional to the vehicle lateral acceleration. The second control gain is inversely proportional to the vehicle lateral acceleration. The second control gain is smaller than the first control gain. A start indication signal is produced when the vehicle is starting. A target torque is calculated. The target torque is proportional to the first control gain and to the wheel speed difference in the presence of the start indication signal. The target torque is proportional to the second control gain and to the wheel speed difference in the absence of the start indication signal.

Abstract: In a vehicle including a torque distributing device for distributing the torque of an engine to left and right driving wheels, a feed-forward control system determines a lateral distribution torque T.sub.1 from an engine torque T.sub.E, a number Ne of revolutions of the engine, a vehicle speed V and a steering angle .theta., and a feed-back control system determines a feed-back torque T.sub.F from a target yaw rate Y determined from the vehicle speed V and the steering angle .theta. and an actual yaw rate Yaw. A final distribution torque T is determined by adding the lateral distribution torque T.sub.1 and the feed-back torque T.sub.D at a predetermined ratio, and an actuator is driven to distribute the engine torque to the left and right driving wheels on the basis of the final distribution torque T.

Abstract: The present invention provides a power transfer system for a four-wheel drive vehicle which permits the vehicle operator to choose between operation in two-wheel drive and part-time four-wheel drive modes or an "on-demand" four-wheel drive mode. The power transfer system is adapted for use in conjunction with automatic disconnect-type drivelines and is operable for disabling the on-demand four-wheel drive feature upon the vehicle operator subsequently shifting into any of the two-wheel drive and part-time four-wheel drive modes.

Abstract: A transfer case for a part-time four wheel drive vehicle includes a planetary gear speed reduction assembly driven by the transfer case input shaft for providing high and low speed range outputs. The planetary gear assembly is disposed between and is selectively engaged by primary and secondary clutch collars, the primary clutch driving the rear (primary) output shaft in either the high or low speed ranges. The secondary clutch drives the front (secondary) output shaft through a chain drive in the low range. The clutch collars are controlled by a single (common) clutch operator. An electromagnetic clutch assembly driven by the input shaft selectively drives the front output shaft chain drive. The electromagnetic clutch functions both as a synchronizer and torque delivery device. The transfer case may be combined with a control which facilitates direct selection of vehicle drive mode.

Abstract: A drive mechanism for an electric car which has a plurality of motors arranged in a drive mechanism case which, in turn rotatably supports a shaft at two points. This shaft transmits the rotation generated by the motors to drive shafts for rotation of the wheels to run the car. The motors are composed of stators having armature cores and coils, and rotors. The stators are fixed in the drive mechanism case and the rotors are supported by the shaft. Since this shaft is rotatably supported at two points by the drive mechanism case, accurate centering of the rotor is maintained.

Abstract: A torque distribution control device includes two rotational speed differential responsive type control couplings each having various transfer torque characteristics which differ in the ratio of a transfer torque to a rotational speed differential. The control device selects one of the torque transfer characteristics in response to a signal supplied thereto. When turning the outer wheel side control coupling is supplied with a signal for selecting the transfer torque characteristic that produces a maximum transfer torque for a given rotational speed differential, and the inner wheel side control coupling is supplied with a signal for attaining a non-slip rotational speed differential and for selecting the transfer torque characteristic that produces a transfer torque equal to that produced by the outer wheel side control coupling when the non-slip rotational speed differential is obtained.

Abstract: A traction controller for a vehicle having a control system for controlling the driving of driving wheels such that the spin quantities of the driving wheels from a road surface become target spin quantities, a mechanism for correcting a control condition based on the lateral acceleration of the vehicle, calculating the actual turning radius Rr of the vehicle, and calculating the steering angle corresponding turning radius Ri of the vehicle. When a tendency for the vehicle to deviate from a running line having the turning radius Ri is marked at the time of turning, the lateral acceleration of the vehicle is calculated based on the turning radius Ri. Consequently, it is possible to prevent the excessive under-steer state of the vehicle.

Abstract: A turn control system for a four wheel drive vehicle which includes an accelerating transmission for driving the right and left steerable wheels at a greater average velocity than the right and left non-steerable wheels. A steering device and a switching device are interlocked such that a change speed device is operable in the accelerating transmission when the steerable wheels are steered in excess of a predetermined angle. An inner one of the steerable wheels with respect to a turning circle has a maximum steering angle .beta.1 which is set to form the following expression:secant .beta.1>Kwhere K is a ratio of the greater average peripheral velocity of the right and left steerable wheels when driven by the accelerating transmission with respect to the peripheral velocity of the right and left non-steerable wheels.

Abstract: The present invention provided a power transfer system for a four-wheel drive vehicle. The transfer system includes a part-time transfer case having an input member rotatably driven by the vehicle's engine, first and second output members operable to rotatively drive respective front and rear axle assemblies, and an intermediate shaft through which power is selectively transferred from the input member to one or both of the first and second output members. In operation, driven rotation of the intermediate shaft causes power to be constantly delivered to the first output member and the front axle assembly for establishing a two-wheel drive mode of operation. Moreover, selective actuation of a mode shift arrangement functions to interconnect the second output member to the intermediate shaft for also delivering power to the rear axle assembly for establishing a four-wheel drive mode of operation.