Fluid filled dampening mechanism utilizing a fluid having a thick viscosity

A dampening disk assembly comprising:

• a pair of plates each having an inner axially facing surface and joined together at a radial outer portion thereof;
• a hub disposed at a generally central portion of said pair of plates, said hub and said axially facing surfaces of said plates defining a generally annular fluid chamber therebetween, said annular fluid chamber being a closed and sealed space that is filled with a viscous fluid, said hub having a contact portion extending partially into said annular fluid chamber;
• an undulated flat-spring disposed in said annular fluid chamber, said undulated flat-spring being compressible between said contact portion of said hub and a contact portion of one of said pair of plates in response to relative rotary displacement between said hub and said pair of plates, said undulated flat-spring having axial edges facing said axial surfaces of said pair of plates;
• and
• a axial gap being defined between each of said axially facing surfaces of said pair of plates and each of said axial edges of said undulated flat-spring, said axial gaps defining a choke for limiting movement of said viscous fluid within said annular chamber in response to compression of said undulated flat-spring, said axial gaps being within a range of 0.1 to 0.6 mm at all portions thereof.