Patent ID: 6161667
Filing Date: 2000-12-19
Classification: F16D

Abstract:
A coupling device comprising:two parts which are coaxially rotatable relative to one another;a friction coupling having friction plates which are alternatively connected to one of said two parts and the other of said two parts, and an actuating device for said friction coupling, said actuating device comprises an annular chamber formed in said one of said two parts and containing a highly viscous fluid, a first rotational member arranged in said annular chamber and drivingly connected to said other of said two parts, and which acts on the highly viscous fluid adhering to it; andsaid actuating device, when said two parts rotate relative to one another, causing an increase in pressure of said highly viscous fluid for the purpose of loading said friction coupling for transmitting torque between said two parts, inside said annular chamber there being provided a second rotational member which is rotatable relative to said one of said two parts to a limited extent to thereby release a short circuit connection between a region of high pressure in said annular chamber and a region of low pressure in said annular chamber, wherein said second rotationally movable member rotates relative to said one of said two parts to release said short circuit connection when the differential speed between said one of said two parts and said other of said two parts exceeds a given differential rotational speed.