Abstract: A power transfer assembly for use in a four-wheel drive vehicle has a torque transfer mechanism equipped with a power-operated clutch actuator for controlling adaptive engagement of a friction clutch and a control system for controlling actuation of the clutch actuator. The control system and its method of operation are adapted to control actuation of the clutch actuator based on whether the vehicle is operating in an engine drive mode or an engine coast/braking mode.

Abstract: A device for setting the torque transmitted by a friction clutch (12), having an actuator chain which comprises an electric motor (45), a step-down gear (42) and a mechanism for converting the rotational movement into a displacement of a pressure plate (29) of the clutch (12), so as to enable the torque which is transmitted to be set precisely and rapidly even given high friction. For this purpose, the electric motor (45) and/or step-down gear (42) is/are affected by friction, the conversion mechanism (31, 32, 35, 36, 40) and/or the friction clutch (12) itself is/are affected by elasticity, and, to set the torque (Md) of the friction clutch (12), a position regulator (47) which is operatively connected to the electric motor (45) and a sensor (46; 46?) which determines the position of one of the links of the actuator chain (45, 42, 41, 40, 36, 35, 32, 31, 29) are provided, the sensor being present at a location upstream of a substantial part of the elasticity in the force-flow direction.

Abstract: A device for setting the torque transmitted by a friction clutch (12), having an actuator chain which comprises an electric motor (45), a step-down gear (42) and a mechanism for converting the rotational movement into a displacement of a pressure plate (29) of the clutch (12), so as to enable the torque which is transmitted to be set precisely and rapidly even given high friction. For this purpose, the electric motor (45) and/or step-down gear (42) is/are affected by friction, the conversion mechanism (31, 32, 35, 36, 40) and/or the friction clutch (12) itself is/are affected by elasticity, and, to set the torque (Md) of the friction clutch (12), a position regulator (47) which is operatively connected to the electric motor (45) and a sensor (46; 46′) which determines the position of one of the links of the actuator chain (45, 42, 41, 40, 36, 35, 32, 31, 29) are provided, the sensor being present at a location upstream of a substantial part of the elasticity in the force-flow direction.

Abstract: A method for controlling a vehicle drive unit, which comprises a drive engine and a transmission with a continuously variable gear ratio, comprises the following steps: a) the required vehicle acceleration (ASOLL) is calculated from a throttle control lever position (XFP, XHG) and the current speed of travel (VFZ), b) a required transmission variation (IGDSOLL1) is calculated from the required vehicle acceleration (ASOLL) and the current rotation speed (NMOT) of the drive engine, c) a limited required transmission variation (IGDSOLL) is determined from the required transmission variation (IGDSOLL1) such that the engine rotation speed (NMOT) does not fall below a value which depends on the position of the power control element (XEP) of the drive engine, d) the continuously variable transmission is varied in accordance with (IGDSOLL); e) the actuation parameter (XEPSOLL) for the power control element of the drive engine is obtained directly from the throttle control lever position (XFP, XHG).

Abstract: A viscous shear coupling for distributing torque between front and rear axles of an all-wheel drive vehicle is provided which comprises a housing, a set of inner blades interdigitating with a set of outer blades, the inner and outer blades being axially spaced apart from each other and axially slidably mounted within the housing, a viscous liquid located within the housing, an adjusting piston within the housing which is axially displaceable so as to adjust the axial distance between adjacent inner and outer blades. The viscous shear coupling further includes a control pressure circuit for delivery of a control pressure fluid to the adjusting piston, a control valve for regulating the delivery of the control pressure fluid to the adjusting piston, and a control device (e.g., a microprocessor) which calculates a desired adjusting piston speed based on driving conditions and adjusts a valve current delivered to the control valve in order to obtain the desired adjusting piston speed.

Abstract: A limited-slip differential gear comprising a differential gear case which is adapted to be driven and in which two coaxial side gears and at least one pair of differential pinions cooperating with each other and associated with the side gears are rotatably mounted, wherein each differential pinion and the associated side gear constitute a worm gear train. In order to reduce the manufacturing costs and the overall size, the worm gear trains comprise worm gears consisting of the side gears and worms consisting of the differential pinions and the differential pinions of each pair have axes extending at an angle to each other and directly mesh with each other.