Abstract: A differential device (17) for use in a four wheel drive system, the device including a viscous coupling (29), a ball ramp actuator (31), and a clutch pack (33). Under normal driving conditions, most of the torque is transmitted to the front drive wheels (11), and the device (17) rotates as a unit. If the front wheels (11) begin to slip, the input shaft (15) and input coupling member (35) rotate faster than the output coupling member (43), thus transmitting torque to the output coupling member (43). This torque is transmitted to the first ramp plate (51) of the ball ramp actuator (31), displacing the actuator from its neutral position (FIG. 3), such that the second ramp plate (52) begins to load the clutch pack (33) and transmit torque from the housing (25) to the output shaft (19), and from there to the rear drive wheels (23).

Abstract: A torsional isolator assembly for reducing driveline torsionals includes a vane damper (36) having valving (40d,40e or 161,163) and chamfers (200,201) on pistons (60 or 160). These chamfers (200,201) aid in forming a seal between a surface (42d or 142d) by creating a hydrodynamic film that biases the piston (60 or 160) toward the housing surface (42d or 142d).

Abstract: Torsion damping isolator assemblies (19 or 100 or 200) are disposed for damping torsionals in a vehicle driveline. The assemblies include spiral springs (62 or 202, 204) and a vane damper assembly (22 or 206) disposed in parallel and immersed in automatic transmission fluid of a torque converter housing (24). Damper assemblies (22 or 206) include first and second relatively rotatable housing members (66, 68 or 208, 210). Housing members (66 or 208) are connected to radially inner ends (62b or 202b, 204b) of the springs, and members (68 or 210) are connected to radially outer ends (62a or 202a, 204a) of the springs. The housing members define chambers which vary inversely in volume in response to flexing of the spring assemblies by driveline torsionals. The chambers communication with the fluid in the torque converter housing via restricted passages (86, 88 or 220f, 220g). As the chambers vary in volume, energy from the torsionals is converted to fluid pressure in the chambers decreasing in volume.

Abstract: A fluid coupling for driving a cooling fan associated with a vehicle in a ram air stream. The coupling comprises relatively rotatable input and output members. The output member defines a chamber within which the input member rotates. The members have lands and grooves which define a shear space therebetween, and are cooperable with viscous shear fluid to transmit torque therebetween. The output member defines a reservoir chamber located forwardly of the lands and grooves in the ram air stream. An impact pumping ramp on the output member directs fluid from the shear space into the reservoir chamber during rotation of the input member. A temperature-responsive valve arrangement controls the flow of fluid from the reservoir chamber to the shear space. The output member has mounting pads against which fan blades are secured. The mounting pads are located axially on the output member between the lands and grooves, and the reservoir chamber and at least, in part, radially outwardly in the lands and grooves.