Viscous damper module for torsional vibration damping mechanism

Claim 1

A torsional vibration damping mechanism in a free standing clutch plate assembly adapted to be rotationally interposed in a driveline between an output drive of a prime mover and an input drive of a transmission; the mechanism comprising: first and second assemblies disposed for relative rotation about a common axis, the first assembly including first and second radially extending, axially spaced apart wall members secured together and adapted for driving connection to the prime mover drive, the second assembly including annular hub means adapted for connection to the transmission input drive, and bearing means for journaling a radially inner extent of at least one of the wall members on the hub means; an intermediate means including a radially extending member disposed between the first and second wall members, the member of the intermediate means drivingly connected to and extending radially outward of the hub means; a spring set disposed between radially inner and outer extends of the wall members, the spring set comprising a plurality of helical compression springs of relatively high spring rate circumferentially spaced apart and resiliently interconnecting the wall members with the intermediate means member, the springs being flexibly operative to attenuate torsionals when the driveline is connected to a load; a friction assembly including first and second axially facing friction surfaces respectively defined on opposite sides of a radially extending flange, the friction surfaces disposed radially outward of the radially outer extent of the wall members, a radially inner portion of the flange fixed to the first assembly, and the friction surfaces adapted to be frictionally clamped between pressure plates of an engagement mechanism defining said input drive; the improvement comprising: a viscous shear damper module disposed axially adjacent the first assembly, said damper module including annular housing and clutch assemblies mounted for relative rotation, the housing assembly having first and second axially spaced apart sidewalls defining a chamber containing a viscous shear liquid with at least one of said sidewalls having an interior surface defining a first clutching surface, said clutch assembly being drivingly connected to one of said means and having a radially extending portion thereof disposed in said chamber, said portion defining a second clutching surface closely spaced from said first clutching surface and in viscous clutching coaction therewith via said viscous shear liquid; and axially extending means fixing a radially outer portion of the annular housing assembly for rotation with the first assembly at positions radially outward of the spring set and radially inward of the axially facing friction surfaces.