Viscous coupling

A viscous coupling comprising two parts which are rotatable relative to one another around a common longitudinal axis, said parts forming an annular chamber which is filled with a highly viscous fluid, first coupling plates connected to the first one of said parts for rotation therewith, second coupling plates connected to the second one of said parts and arranged so as to alternate in the longitudinal direction with said first coupling plates, said second coupling plates being alternately arranged with clamping rings on said second one of said parts, said clamping rings in turn, being connected to said second one of said parts for rotation therewith;

• a first axial adjusting device which acts on said second coupling plates and on said clamping rings in an axial direction and locks the same relative to one another and to said second one of said parts, said first axial adjusting device having a ball/ramp mechanism with a pressure ring connected to one of said parts and rotationally connected therewith and axially displaceable, a freely rotatable setting ring brakable relative to the other one of said parts, wherein balls are arranged between both of said rings, wherein said balls are held in ramplike circumferential grooves in opposing faces of said rings;
• a brake assembly for said setting ring having a second viscous coupling with a second annular chamber filled with a highly viscous fluid in which third coupling plates are connected to said setting ring for rotation therewith, and fourth coupling plates are connectable to the said other one of said two parts, and are arranged so as to alternate in the longitudinal direction with said third coupling plates, and wherein said fourth coupling plates are arranged so as to alternate with second clamping rings on said other one of said parts, said second clamping rings being, in turn, connected to rotate with said other one of said parts;
• and a second axial adjusting device for said brake assembly for said setting ring.