Valving for vane damper

A torsion isolator assembly adapted to be disposed for rotation about an axis in a driveline torque converter housing filled with an incompressible torque converter fluid, the assembly immersed in the fluid and drivingly connected between first and second rotatably mounted drives;

• the assembly comprising resilient means for transmitting driveline torque between the drives and a hydraulic coupling for damping torque fluctuations in response to flexing of the resilient means;
• the coupling including first and second relatively rotatable housing means defining an annular chamber having radially spaced apart cylindrical surfaces and first and second axially spaced apart end surfaces, the cylindrical surfaces and the first end surface defined by the first housing means, and circumferentially spaced apart walls sealingly fixed to the first housing means and extending radially and axially across the annular chamber for dividing the annular chamber into at least two independent arcuate chambers;
• a piston disposed in each arcuate chamber for dividing each arcuate chamber into pairs of first and second volumes which vary inversely in volume in response to movement of the pistons relative to the first housing means, each piston having radially oppositely facing surfaces in sliding sealing relation with the chamber cylindrical surfaces, having first and second axially oppositely facing end surfaces in sliding sealing relation respectively with the first and second end surfaces of the chamber, and having first and second circumferentially spaced apart and oppositely facing surfaces respectively intersecting the first and second oppositely facing end surfaces;
• the second housing means including an annular radially extending housing member having an axially facing surface defining the second end surface of the annular chamber, the second end surface being in sliding sealing relation with each piston second end surface, the housing member being in sliding sealing relation with portions of the first housing means and retained against axial movement in a direction away from the first end surface of the annular chamber by means affixed to the first housing means, and the housing member having a set of circumferentially spaced and axially extending through openings;
• piston drive means for connecting the pistons to the first drive via a path independent of the resilient means, the piston drive means extending through the housing member openings with circumferential free play therebetween for allowing limited to-and-fro circumferential movement of the pistons relative to the housing member;
• housing drive means for connecting the first housing means to the second drive independent of the resilient means;
• and passage means for effecting fluid communication of the pairs of volumes with the fluid in the torque converter housing;
• characterized by:
• the passage means including fluid passages extending through the housing member, for communicating the torque converter fluid with each volume via first and second paths associated respectively with the first and second volumes, portions of the sealing relation between the pistons and the housing member movable to positions blocking the first paths and unblocking the second paths in response to flexing of the resilient means in a direction tending to decrease and increase the first and second volumes respectively, and the portions movable to positions blocking the second paths and unblocking the first paths in response to the flexing tending to decrease and increase the second and first volumes, respectively.