Abstract: A variable biasing differential provides an adjustable torque bias between two outputs. An input shaft provides drive torque to a carrier which receives a plurality of stub shafts and a like plurality of planet gears. A first set of planet gears drives a first sun gear and first output and a second set of planet gears, which, in turn, drives additional planet gears which drive a second sun gear and second output. Secured to both ends of the carrier are first and second ring gears which each mesh with an eccentric gear which in turn includes an eccentric second ring gear which meshes with an internal gear disposed about the first and second outputs. These gears are coupled to respective first and second friction clutches which can be independently activated to adjust the torque bias of the differential.

Abstract: A synchronizer for motor vehicle driveline components such as transmissions and transfer cases includes a pair of ball ramp mechanisms which amplify synchronizing force and apply such force to one of a pair of friction clutch packs which achieves synchronization of diversely rotating elements. The synchronizer exhibits relatively low operating force. Each ball ramp mechanism includes a pair of ball ramp members having rotational travel limits which also limit their axial separation and an intermediate compression spring assembly. The spring assembly and the travel limits of the ball ramp members limit the force generated by the ball ramp mechanisms and applied to the friction clutch packs to prevent abrupt and uncontrolled actuation of the friction clutch packs and corresponding abrupt synchronization of the rotating elements.

Abstract: A method and apparatus for a four-wheel drive motor vehicle provides improved cornering by disengaging drive torque to the inside rear wheel during significant steering maneuvers. The apparatus includes a primary front wheel drive motor vehicle driveline having a center differential which provides drive energy to the primary (front) driveline and secondary (rear) driveline and a rear axle assembly having a pair of normally engaged (active) clutches which provide drive energy to the respective rear wheels. A steering angle sensor detects angular displacement of the steering column or front (steering) wheels and an associated controller disengages the clutch associated with the rear wheel on the inside of the turn as determined by the steering angle sensor.

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.

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 yaw damper for a front wheel drive vehicle provides torque transfer between the two non-driven wheels and generates a damping yaw moment in opposition to the current vehicle yaw condition. The yaw damper is passive and includes a mechanical clutch or fluid connection between the two non-driven wheels which transfer yaw correcting torque. The mechanical clutch includes first and second pluralities of interleaved friction disks which are coupled by shafts to respective non-driven wheels. A spring compresses the clutch pack and limits torque transfer between the shafts and wheels to a pre-selected maximum torque. In another embodiment, positive displacement pumps driven by each of the non-driven wheels are connected in series and transmit torque in proportion to the speed difference. In another embodiment, nested shafts include centrifugal clutches which transfer torque in proportion to vehicle speed and difference.

Abstract: A yaw damper for a front wheel drive vehicle provides torque transfer between the two non-driven wheels and generates a damping yaw moment in opposition to the current vehicle yaw condition. The yaw damper is passive and includes a mechanical clutch or fluid connection between the two non-driven wheels which transfer yaw correcting torque. The mechanical clutch includes first and second pluralities of interleaved friction disks which are coupled by shafts to respective non-driven wheels. A spring compresses the clutch pack and limits torque transfer between the shafts and wheels to a pre-selected maximum torque. In another embodiment, positive displacement pumps driven by each of the non-driven wheels are connected in series and transmit torque in proportion to the speed difference. A pressure relief valve limits the maximum pressure in the fluid lines and thus the maximum torque transfer.

Abstract: An apparatus and method of operating an adaptive drive system of a motor vehicle which reduces drive line wear, improves safety margins and permits weight reduction in drive line components activates a clutch between a primary and secondary drive line when the vehicle is determined to be heavily loaded. The method steps include sensing the position of a throttle position sensor, sensing the instantaneous speed of a motor vehicle and computing instantaneous acceleration, determining whether the ratio of vehicle acceleration to throttle position is less than predetermined threshold value and engaging a transfer case clutch to transfer drive torque from a primary drive line to a secondary drive line. Operation of this method is transparent to the driver inasmuch as the clutch is activated when the vehicle is heavily loaded as determined by the throttle position to acceleration ratio.

Abstract: A clutch assembly for disposition in a motor vehicle drive line includes an internal reaction force circuit. The clutch assembly includes a multiple disc friction clutch disposed adjacent an operator assembly which selectively applies force to the friction clutch to selectively transfer torque therethrough. The clutch components are disposed between fixed stops on an elongate member which functions as a reaction force member to self-contain the reaction force from the clutch operator. The clutch finds application in motor vehicle drive line components such as a rear (secondary) axle in which it is disposed in pairs to independently control torque supplied to each axle and in applications where it is advantageous to contain or ground the reaction force generated by and associated with the clutch operator compactly within the clutch structure rather than its housing.

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: 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 transfer case adapted for installation on a front-wheel drive vehicle having a transversely oriented engine and transaxle receives drive torque on a transferse axis and provides it to the rear differential on a longitudinal axis. The transfer case is driven through the front axle center differential cage. A drive chain delivers power through sprockets to a modulating or viscous clutch disposed behind and parallel to the front stub axles. The output of the clutch is provided to a bevel gear set which drives the rear prop shaft, rear differential and rear axles. The transfer case and rear prop shaft are preferably disposed along the longitudinal center line of the vehicle. Alternatively, the transfer case and the rear prop shaft may be disposed along an axis laterally offset but parallel to the longitudinal center line of the vehicle.

Abstract: Shift control assembly for a power transmission device includes an electric drive motor and gear train having an output which is coupled to and bi-directionally rotates a shift rail. The shift rail includes a pair of spaced-apart cam followers. Freely rotatably receiving the shift rail and disposed thereon between the cam followers is a shift fork assembly. The shift fork assembly includes a body having a pair of spaced-apart helical cam surfaces engaged by the cam followers and a fork engaging a shift clutch collar. As the shift rail rotates bi-directionally, the shift fork assembly and clutch collar bi-directionally translate. A circular plate is disposed for rotation with the shift rail and includes an array of apertures. A plurality of sensors are disposed in adjacent, sensing relationship to the circular plate.

Abstract: A transfer case for a four-wheel drive vehicle includes a center differential which provides a direct output in two-wheel drive and a slightly reduced speed output in four-wheel drive. In two-wheel drive, the outputs of the center differential are locked together by a clutch collar and drive torque is provided to the primary drive line only. In four-wheel drive, the clutch collar unlocks the differential and couples the output from a sun gear to a chain drive sprocket in the secondary drive line. The center differential is driven through the carrier and operates as an open differential. The ring (outer) gear drives the primary drive line and the sun (center) gear drives the secondary drive line through cooperating chain sprockets and a chain. The chain drive sprockets are of unequal size and effect a speed reduction between the drive and driven sprockets. This speed reduction is nominally the same as the speed reduction from the input to the primary output achieved through the center differential.

Abstract: An adaptive torque control and distribution system for a motor vehicle having a transfer case, primary driveline and drive wheels and secondary driveline and drive wheels for operation in extreme off road conditions such as sand. The transfer case includes a modulating clutch and a lockup clutch disposed in parallel between its primary (rear) output and secondary (front) output. The system detects abnormally high magnitude and rapidly repeating wheel spin transients which are characteristic of operation in sand or similar highly randomly variable tractive conditions and overrides the on demand torque distribution program for a predetermined time interval. During this predetermined time interval, the transfer case lockup clutch is activated thereby coupling the primary and secondary drivelines and achieving a fifty-fifty torque split therebetween while the modulating clutch is inactive.

Abstract: An electromagnetic clutch assembly for motor vehicle transfer cases and the like includes an electromagnetic operator and a disc pack clutch assembly disposed on opposite sides of a chain drive sprocket. The clutch pack assembly is driven by a primary output shaft of the transfer case and transfers energy to the chain drive sprocket and thence to a secondary output shaft. The disc pack clutch assembly is actuated by the clutch operator which generates a compressive force which is transferred to the clutch pack assembly by a plurality of axially disposed pins received within complementary passageways in the chain drive sprocket.

Abstract: An acceleration sensitive double overrunning clutch is directionally preset by a change in speed, i.e., acceleration, rather than relative rotation. The clutch is especially adapted for use in power transmission devices such as motor vehicle transfer cases. The clutch includes a plurality of rollers disposed in a like plurality of spaces having symmetrically arranged oblique walls formed by adjacent portions of an inner member and a concentric outer member. The rollers are arranged within a spacing cage which is coupled to an annular weight. A speed change, i.e., acceleration or deceleration, shifts the weight and presets the cage and rollers to function in their engaged or overrunning modes in one direction or the other depending upon the direction of such acceleration.

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 transfer case having a mechanically parallel overrunning clutch and centrifugal, speed proportional clutch provides improved handling characteristics especially in off-throttle driving conditions. The transfer case includes a one-way or overrunning clutch which provides drive from the rear driveline to the front driveline to rotate the front driveline and wheels at least as fast as the rear driveline and wheels. For example, the one-way clutch will be engaged when the rear drive wheels lose traction and attempt to overspeed the front drive wheels. The clutch overruns, however, if the front driveline and wheels are urged to overrun the rear driveline. The mechanically parallel speed responsive, i.e., centrifugal, clutch provides speed proportional engagement or coupling between the two drivelines and is particularly effective to reduce speed differences therebetween as its clutching and torque transfer effects are in direct proportion to the speed difference between the two drivelines.

Abstract: An active multi-mode overrunning clutch assembly includes concentric inner and outer members and a plurality of opposed pairs of clutch pawls operably disposed between the members. The clutch pawls are biased radially outwardly and include recessed portions and raised lands which cooperate with an axially translatable circumferential control sleeve. The control sleeve can be translated to select various combinations of active (engaged) or inactive (retracted) pawls to effect four distinct operational modes: fully engaged, i.e., locked in both directions, drive and overrunning in a first direction, drive and overrunning in the reverse direction and fully disengaged, i.e., released or inactive. The active multi-mode overrunning clutch assembly finds particular application in transfer cases of four wheel drive vehicles.