Abstract: A power transfer apparatus is provided with a rack/pinion type electric shift actuator for changing a traveling mode of a vehicle between high speed mode and low speed mode, and among full-time 4WD mode, 2WD mode, high direct-coupling 4WD mode and low direct-coupling mode. The apparatus further has a hydraulic multiple disc clutch for restricting a differential motion of a center differential gear when the traveling mode is in full-time 4WD mode and the traveling mode is changed over, and a hydraulic pump connected to a counter shaft, for supplying hydraulic pressure to the hydraulic multiple disc clutch.

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 coupling assembly has at least one friction coupling unit which comprises a driveable housing and a hub to be driven, and having differential-speed-dependent actuating means operating by a pressure agent and comprising a pump unit. The pump unit comprises housing parts and hub parts, which housing parts are rotatable relative to said hub parts with the one part of the pump unit being connected in a rotationally fixed way to the housing of the friction coupling unit and the other parts of the pump unit being connected in a rotationally fixed way to the hub of the friction coupling unit. The hub of the at least one friction coupling unit is receiving an outer joint part of a constant velocity universal joint.

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

Abstract: 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 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 compound type planetary gear set lacking ring gears has been applied to a differential limiting apparatus for distributing driving force between left and right wheels of a vehicle. The driving force conveyed from an engine is inputted to a first sun gear through a differential case and dividedly transmitted to a second sun gear through first and second pinions composed of helical gears and to a carrier supporting the first and second pinions, respectively. The driving force conveyed to the second sun gear is transmitted to a left drive axle and the driving force conveyed to the carrier is transmitted to a right drive axle. When slipping occurs in the left or right wheels, the first and second pinions rotate around the first and second sun gears. The helix angles of the first and second pinions produce thrust forces which generate a differential limiting torque between the left and right drive axles.

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: An automatic transmission for an automotive vehicle includes a continually variable drive mechanism having one sheave assembly fixed to an intermediate shaft and the input sheave assembly supported on an input shaft, a low speed gearset driveably connected to the input shaft and an output shaft, a fixed ratio drive mechanism in the form of a chain drive providing a torque delivery path between the intermediate shaft and the carrier of the gearset, a transfer clutch for connecting and releasing the first sheave of the variable drive mechanism and input shaft, a low brake, a reverse gearset, a reverse brake, and a clutch for selectively driveably connecting the output of the fixed drive mechanism and a front output shaft.

Abstract: In one aspect of the present invention, a method for controlling the steering of a directionally steered machine having a hydrostatic system that drives a plurality of driven wheels is provided. The method includes the steps of producing a steering angle signal indicative of the angle of the steered wheels and a wheel speed signal indicative of the rotational speed of the driven wheels, and generating a programmable curve that represents the resulting driven wheel speeds as a function of the angle of the steered wheels. The generated curve is then stored in a software map to be later used to determine the driven wheel speeds based on the angle of the steered wheels.

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 torque distribution control system for an automotive vehicle comprises a friction clutch adapted to distribute an engine power between front and rear road wheels or between left and right road wheels, a sensor provided for monitoring wheel speeds, a control unit being responsive to the wheel speeds for computing a wheel-speed difference and for computing a command signal value indicative of an engagement force to be applied to the friction clutch in response to the wheel-speed difference, and an actuating device for actuating the friction clutch in response to the command signal value. The control unit has a processor for discriminating whether the vehicle is in a specified running state in which it is possible to precisely compute a specific wheel-speed difference, occurring due to a difference in outside diameter of tires.

Abstract: The invention provides a hydromechanical system for limiting differential speed between first and second rotating members of a vehicle drivetrain subassembly. The hydromechanical system comprises a casing disposed within a housing of the subassembly which is rotatably coupled to the first rotating member of the drivetrain subassembly. Hydraulic fluid is supplied from a sump within the drivetrain subassembly housing to a reversible hydraulic pump disposed within the casing, wherein the reversible hydraulic pump pumps hydraulic fluid in response to relative rotation between the first and second rotating members. A piston assembly is disposed within the casing which includes a guide member, an actuating member and a chamber disposed therebetween, wherein the chamber receives the pumped hydraulic fluid.

Abstract: A drive train for a four wheel drive vehicle including an engine and a clutch directing power through a high/low transmission to a six speed transmission located adjacent to and parallel with the engine in an expanded engine sump case. A constant velocity joint is driven from one end of the transmission output shaft for driving a rear differential associated with an independent rear suspension. From the other end of the transmission output shaft, a fluid coupling is employed to selectively engage a front differential. The front differential drives gear wheels to engage back to back constant velocity joints which are located lower than the differential rotational axis to advantage the suspension configuration.

Abstract: A transmission for a four-wheel drive vehicle having a multi-speed geartrain and power transfer mechanism incorporated into a common housing assembly. The multi-speed geartrain includes a input shaft, a mainshaft, and a plurality of constant-mesh gearsets arranged for selectively coupling the mainshaft to the input shaft for driven rotation at various speed ratios. The mainshaft can be selectively coupled to the power transfer mechanism for establishing two alternative power transmission routes. In particular, a synchronized range shift mechanism is provided for establishing a high-range transmission route and a low-range transmission route from the mainshaft to 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. As an option, a lock-out clutch can be provided for permitting the interaxle differential to be locked for establishing a locked four-wheel drive mode.

Abstract: A transfer case for a four-wheel drive vehicle having a planetary gear assembly which integrates a gear reduction unit and an interaxle differential into a common assembly. A synchronized range clutch is operably associated with the input to the planetary gear assembly and can be selectively shifted on-the-fly for establishing high-range and low-range speed ratios. A biasing clutch is operably associated with the output of the planetary gear assembly to automatically limit speed differentiation and bias the torque distribution between the outputs of the planetary gear assembly in response to excessive wheel slip.

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: The transmission of the present invention includes a multi-speed geartrain comprised of an 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 arrangement for establishing two alternative power transmission routes. In particular, the range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to a quill shaft which, in turn, drives the interaxle differential. The torque delivered by the quill shaft is split by the interaxle differential between the front and rear drivelines to establish the full-time four-wheel high-range and low-range drive modes.

Abstract: A differential apparatus for a part-time four-wheel drive vehicle is provided. The differential apparatus includes an outer differential casing, an inner differential casing, a clutch member adjacent to the inner differential casing, a pair of dog clutches, a differential gear system arranged in the inner differential casing and an actuator body for actuating the clutch member. One of the dog clutches is connected with the inner differential casing, while the other of the dog clutches is formed on the clutch member. When the vehicle is traveling under two-wheel drive, the inner differential casing and the differential gear system are raced, while the outer differential casing and the clutch member do not race. Accordingly, it is possible to reduce the racing loss of these members and the noise caused by the racing loss.

Abstract: A transmission includes a multi-speed geartrain comprised of an 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 arrangement for establishing two alternative power transmission routes. In particular, the range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to a quill shaft which, in turn, drives the interaxle differential. The torque delivered by the quill shaft is split by the interaxle differential between the front and rear drivelines to establish the full-time four-wheel high-range and low-range drive modes. Optionally, the torque transfer apparatus can be provided for controlling speed differentiation across the interaxle differential or in place of the interaxle differential for on-demand four-wheel drive operation.

Abstract: A hydraulic-pressure control system for a four-wheel drive vehicle with a hydraulic-pressure operated transfer clutch, which is responsive to a controlled clutch pressure applied thereto to distribute a driving torque passing from a transmission between main drive wheels and auxiliary drive wheels, comprises a pilot-operated directional control valve connected to the transfer clutch for cutting off a supply of hydraulic fluid of the controlled clutch pressure to the transfer clutch and for directing hydraulic fluid of the controlled clutch pressure to the transfer clutch. The system includes a clutch pressure control valve provided upstream of the directional control valve, which pressure control valve is responsive to an external pilot pressure for producing the controlled clutch pressure, and a duty-ratio controlled solenoid valve for decreasingly adjusting the external pilot pressure to be output to the pressure-reduction valve in accordance with an increase in a duty ratio.

Abstract: A differential control unit for a 4-wheel drive vehicle is disposed between a transmission and a propeller shaft, controls a violator of the speed regulations between front and rear wheels generated when turning the 4-wheel drive vehicle, and limits the torsion stress by its violator of the speed regulations so that it can improve driving performance and keep the vehicle stable.

Abstract: In a process for hydrostatically driving a vehicle comprising at least two ideal axles (12) of which each has at least one drivable wheel (11), each drivable wheel (11) being driven by at least one hydraulic motor (9) connected to at least one hydraulic source (6), and the driving power being transmitted from a hydraulic motor (9) via a transmission system (10, 35) to the respective wheel (11), the vehicle is to be usable under different performance requirements and is to be produced and operated in a simple and inexpensive manner. This is achieved in that the drivable wheels (11) are initially driven with a first identical ratio of the transmission system (10, 35), while, when a first load limit is reached, the effective drive of the wheels (11) of at least one ideal axle (12) is reduced and, when a second load limit is reached, the ratio of the transmission system (10, 35) is changed, and at least the wheels (11) driven before the first load limit are equally driven.

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: In a driving force control system for a vehicle, an angular velocity of the course direction of the vehicle body is calculated. On the other hand, a target angular velocity of the course direction is determined based on a steering angle and a vehicle speed. Then, based on the degree of the deviation of the calculated angular velocity from the target angular velocity, a correction coefficient for reducing an engine power is generated. When the vehicle traces off the course in the marginal condition on the low friction coefficient road, the correction coefficient reduces the engine power to prevent the vehicle from going out of the course.

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: 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: An active torque-split control system for a four-wheel-drive vehicle comprises a transfer clutch, and sensors for detecting a wheel-speed difference between a primary drive wheel and a secondary drive wheel, a throttle opening, a vehicle speed, depressed or undepressed states of a brake pedal. The system is capable of executing both a feedback control based on the wheel-speed difference and a feedforward control based on the throttle opening. The system is responsive to at least a feedback control signal from the feedback control system and an anticipating correction signal from the feedforward control system for determining a distribution ratio of driving torque of the secondary drive wheel to the primary drive wheel depending on the highest one of the feedback control signal value and the anticipating correction signal value.

Abstract: A method and apparatus for operating a power transfer device such as a vehicle transfer case having, shaft speed sensors, a two speed (high-low) drive assembly, an electrically, pneumatically or hydraulically operated shift operator and a microprocessor comprising the steps of sensing the speeds of the transfer case input shaft and output shaft, calculating the rate of change (.DELTA.S/.DELTA.t) of the speed of the input shaft, predicting, based upon such rate of change, a time when the input shaft and the output shaft will be synchronized and commencing movement of such shift operator at a time prior to such synchronization in order to effect engagement of such clutch into high gear at substantially the instant of synchronization.

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: A driving-torque distribution control system for a four-wheel drive vehicle, comprises a transfer having a transfer clutch for variably adjusting a front and rear drive-wheel torque distribution, and a torque-split controller for setting a weighting coefficient to a lower speed of rotational speeds of secondary drive wheels depending on a wheel-load shift between the secondary drive wheels e.g. a lateral acceleration exerted on the vehicle or a rolling moment. The controller calculates a simple mean of rotational speeds of primary drive wheels, and also calculates a weighted mean of rotational speeds of the secondary drive wheels based on the weighting coefficient so as to control the transfer clutch in accordance with the front and rear drive-wheel torque distribution based on a difference between the simple mean and the weighted mean. The weighting coefficient is held constant until the lateral acceleration exceeds a predetermined threshold.

Abstract: A traction control system for a fourwheel drive vehicle having a center differential comprises a brake pressure control apparatus, an engine output control apparatus, a differential limiting torque control apparatus, vehicle speed calculating means for calculating a reference vehicle speed of a vehicle, slip amount calculating means for calculating a slip amount of each wheel, target slip amount determining means for determining a front target slip amount of front wheels and a rear target slip amount of rear wheels, traction control determining means for determining to operate a traction control when the slip amount of the front wheels exceeds the front target slip amount or when the slip amount of the rear wheels exceeds the rear target slip amount, brake pressure calculating means for calculating a brake pressure so as to apply a brake to the wheels and engine output calculating means for calculating a target engine torque corresponding to a difference between the slip amount and the target slip amount, whe

Abstract: A power transfer system for a four-wheel drive vehicle is having a part-time transfer case with its input angled relative to its outputs by means of a constant velocity (CV) universal joint. More specifically, the transfer case input includes a first rotary member adapted to be rotatably driven about the rotary axis of the transmission output shaft, a second rotary member supported for rotation about a second rotary axis that is angled relative to the first rotary axis, and a CV joint interconnecting the first and second rotary members. The transfer case outputs include a pair of rotary output members supported for relative rotation about a common third rotary axis that is offset from the second rotary axis. A torque transfer arrangement is provided for transferring torque from the transfer case input to its outputs. As such, the CV joint allows the transfer case to be angulated so that reduced departure angles are achieved with respect to the prop shaft connections.

Abstract: A method of controlling a rotary vehicle to navigate a heading using a conation of translational and rotational motions by a plurality of driving-steering wheels controlling the motion in three degrees of freedom for a manned or unmanned vehicle having at least two drive-steering wheels, wherein a drive-steering wheel is a wheel with its heading orientation and driving velocity positively controlled, wherein a global motion is a vehicle trajectory with vehicle orientation from the initial position (with orientation) to a final destination (with orientation), which comprises comparing a global motion selected to the vehicle's body position and orientation to compute a motion instruction in three degrees of freedom, the acceleration, path of curvature, and rotation rate, collectively known as the motion command then converting the motion command into a translational speed, a translational direction, and a rotational rate and converting the translational speed, the translational direction and the rotational rate

Abstract: The transmission of the present invention includes a multi-speed geartrain comprised of an 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 arrangement for establishing two alternative power transmission routes. In particular, the range shift mechanism is provided for establishing a high-range power transmission route and a low-range power transmission route from the mainshaft to a quill shaft which, in turn, drives the interaxle differential. The torque delivered by the quill shaft is split by the interaxle differential between the front and rear drivelines to establish the full-time four-wheel high-range and low-range drive modes.

Abstract: A transfer case for a four-wheel drive vehicle having a planetary gear assembly which integrates a gear reduction unit and an interaxle differential into a common arrangement. A clutch apparatus is operably associated with the planetary gear assembly and can be selectively shifted on-the-fly for establishing a full-time four-wheel high-range drive mode, a neutral non-driven mode, and a full-time four-wheel low-range drive mode.

Abstract: A driving-torque distribution integrated control system for a four-wheel drive vehicle, for controlling a driving torque distribution between front and rear wheels and a driving torque distribution between right and left wheels, comprises a first torque distribution control section responsive to a first control command for controlling a front-and-rear driving torque distribution between subsidiary drive wheels installed at a first side of front and rear sides of the vehicle and primary drive wheels installed at a second side of the front and rear sides, and a second torque distribution control section responsive to a second control command for controlling a right-and-left drive torque distribution between said primary drive wheels. First and second target slip arithmetic units derive target slip states for the subsidiary drive wheels and for an outer drive wheel of the primary drive wheels, and first and second actual slip arithmetic units derive the actual slip of the subsidiary and outer drive wheels.

Abstract: A power transfer system is disclosed for a four-wheel drive vehicle operable for permitting a vehicle operator to select between various full-time and part-time four-wheel drive modes. The power transfer system includes a transfer case equipped with a single-planetary gear reduction unit and a synchronized range shift mechanism operable for permitting the vehicle operator to shift on-the-fly for establishing full-time and part-time high-range and low-range four-wheel drive modes. The transfer case is also equipped with an electronically-controlled slip limiting/torque biasing arrangement including an interaxle differential and a transfer clutch operable for controlling the magnitude of speed differentiation and torque biasing across the interaxle differential.

Abstract: A speed reduction and differential mechanism assembly includes an input shaft; first and second output shafts; a planetary gearset comprising a sun gear, ring gear, carrier and planet gears rotatably supported on the carrier and in continuous meshing engagement with the sun gear and ring gear: and means for shifting the gearset between positions spaced mutually along the input shaft, a first position where the input shaft driveably engages the sun gear, the first and second output shafts driveably engage the carrier and the ring gear is held against rotation; a second position where the input shaft driveably engages the carrier, the sun gear driveably engages the first output shaft, and the ring gear driveably engages the second output shaft.

Abstract: An automobile driving-torque distribution control system for controlling a torque distribution between front and rear road wheels, comprises a torque-distribution adjustment mechanism responsive to a control signal for adjusting a distribution of driving torque between the front and rear wheels, sensors for detecting front and rear wheel speeds, and a controller for producing the control signal based on the difference between the front and rear wheel speeds. The controller includes a correction circuit for correcting the control signal value, to keep the control signal value at a designated torque-distribution limiting value when satisfying both a first condition in which the wheel-speed difference decreases to a value below a predetermined threshold, and a second condition in which an elapsed time calculated from the time when the first condition has been satisfied, is less than a predetermined time period.

Abstract: It is an object of this invention to make compact a system for controlling the distribution of a driving force and also to simplify its controlling procedure. To achieve this object, a motor 200, 2200 is designed to be electrically controlled, and the rotation of the motor is transformed to the stroke of a plunger 370, 2370 by a hydraulic pressure producing cylinder device 300. By doing this, a hydraulic pressure is produced within a hydraulic pressure chamber 376, 2376 and the hydraulic pressure thus produced is supplied to an operating cylinder 40. The operating cylinder 40 controls a gain of an engagement force of a variable torque clutch device 30. Also, it is another object of the present invention to provide a fail-safe technique for a hydraulic pressure supply device of the motor drive type.

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 power transfer system for a four-wheel drive vehicle having a full-time transfer case with its input angled relative to its outputs by means of a constant velocity (CV) universal joint. More specifically, the transfer case input includes a first rotary member adapted to be rotatably driven about the rotary axis of the transmission output shaft, a second rotary member supported for rotation about a second rotary axis that is angled relative to the first rotary axis, and a CV joint interconnecting the first and second rotary members. The transfer case outputs include a pair of rotary output members supported for relative rotation about a common third rotary axis that is offset from the second rotary axis. A torque transfer arrangement is provided for transferring torque from the transfer case input to its outputs. The CV joint allows the transfer case to be angulated so that reduced departure angles are achieved with respect to the prop shaft connections.

Abstract: A vehicle yaw control for a vehicle having wheel brakes wherein the wheel brakes complement driver controlled steering efforts by establishing a maximum steering angle that can be used for any given coefficient of friction at the wheel-road interface and for any given speed, thereby achieving optimum lateral control during turning maneuvers by compensating for under-steering and over-steering for each driving condition.

Abstract: A driving power transfer apparatus for four-wheel drive automotive vehicles, has a primary output shaft for providing driving power for a rear propeller shaft and a secondary hollow output shaft for providing driving power for a front propeller shaft, and a drive power transfer, such as a fluid coupling, mounted on the secondary output shaft, for variably transmitting the driving power to the secondary output shaft from the primary output shaft. The secondary shaft is connected to a front propeller shaft via a splined sliding yoke.

Abstract: A four wheel drive motor vehicle is of a type which has a variable torque transfer through which the driving force distribution between front and rear wheels is varied in accordance with the magnitude of a fluid pressure supplied to the transfer. A fluid pressure control device for producing the fluid pressure comprises a first hydraulic circuit which is arranged to have a first operation mode wherein the first hydraulic circuit outputs, for the transfer, a fluid pressure which is varied continuously; a second hydraulic circuit which is arranged to have a second operation mode wherein the second hydraulic circuit outputs, for the transfer, a fluid pressure which is varied stepwisely; a piping for connecting the first and second hydraulic circuits to constitute a united hydraulic circuit; and shutters arranged in given portions of the piping to selectively open and close the given portions for allowing the united hydraulic circuit to have the first and second operation modes selectively.

Abstract: An integrated control system for integrally controlling operations of an electronic torque split system and a traction control system for an automotive vehicle is provided. This system is such that when slippage of auxiliary driven wheels to which engine torque is variably delivered exceeds an auxiliary wheel target slippage value which is determined in a preselected relation to a cornering condition, the torque split system modifies an amount of engine torque distribution to the auxiliary wheels so that the auxiliary wheel slippage is adjusted toward the auxiliary wheel target slippage value, while the traction control system is activated to reduce an excess of engine torque constantly delivered to primary driven wheels for maintaining primary driven wheel slippage within a preselected allowable range.

Abstract: A control system/method for determining vehicular gross combined weight (GCW) is provided. GCW is determined immediately after upshifts of a transmission (10) and requires only input signals indicative of engine or driveline torque (DL), vehicle acceleration (dOS/dt) and currently engaged gear ratio (GR).

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 clutch actuating device for use in a vehicle drivetrain subassembly having a clutch and a rotatable drive member, comprising a first rotating member which is coupled to the drive member and a second rotating member which is free to rotate relative to the drive member. The first and second rotating members are differentially driven by a gear device and may include first and second ramp surfaces which engage one another so as to permit axial translation of the members relative to one another or alternatively, may comprise threaded screw members which engage one another so as to permit axial translation relative to one another. First and second pilot clutches comprising at least one rotatable plate are provided, with at least one of the pilot clutches being connected to the gear device.