Hydraulic torsional vibration damper

The hydrodynamic converter having an input member and an output member;

• damping means for connecting said input member and said output member in direct drive relationship;
• said damping means including a lock-up plate with an inboard and an outboard surface and means for imposing hydrodynamic convertor pressure on the inboard surface for moving said lock-up plate in a direction to be coupled to said input member;
• means carried by said output member engageable with said damping means for operating said damping means upon relative rotation between said input member and said output member in a first direction;
• said damping means including a spring diaphragm connected to said lock-up plate for forming a sealed fluid filled damping chamber on the inboard surface thereof;
• cam means carried by said lock-up plate and cam follower means responsive to relative rotation between said input member and said output member to shift said spring diaphragm to vary the volume of said damping chamber and to absorb torsional vibrations;
• and
• fluid restriction means for controlling flow of liquid from a liquid source to said damping chamber in accordance with the relative velocity of said input and output members for imposing a force on said lock-up member to damp relative rotation between said input member and said output member as said lock-up member is directly coupled to said input member.

The hydrodynamic converter damping mechanism for damping engine vibrations in a vehicle drive train when a lock-up plate is engaged with a rotatable convertor input housing of the hydrodynamic converter for directly coupling the rotatable housing to an output member of the hydrodynamic converter as a hydraulic pressure differential is applied across the inboard and outboard surfaces of the lock-up plate to a relief chamber on the opposite side of the lock-up plate which relief chamber is selectively connected to a sump of a hydraulic supply which is connected to the hydrodynamic converter for charging the high pressure chamber, said damping mechanism comprising:

• hydraulic damping means including means forming a liquid filled variable volume chamber for imposing a vibration damping force on said lock-up plate for damping engine vibrations between said input member and said output member as the lock-up plate engages said input member;
• said means forming said variable volume chamber including a first ring on said lock-up plate having a radially inwardly located sealing surface formed circumferentially thereof;
• a second ring having an annular shoulder supported within said sealing surface and further including a radially inwardly located cam surface thereon;
• means for connecting said second ring for rotation with said output member;
• a third ring supported within said second ring and coacting sealing surfaces on said third ring and said second ring for sealing therebetween;
• said third ring having cam follower tabs thereon engageable with said cam surface of said second ring for causing said third ring to shift axially of said second ring upon relative rotation between said input member and said output member;
• and
• fluid restriction means for controlling flow of liquid into and from said variable volume chamber in accordance with the rate of relative rotation between said input member and said output member of said hydrodynamic converter so as to control the level of damping torque on said lock-up plate in accordance with the relative movement between said input member and said output member.