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 and 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 intersecting the first and second 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, and the piston drive means connected to each piston at a position intermediate the first and second circumferentially facing surfaces thereof;
• 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 first and second recesses in each piston second end surface and respectively extending circumferentially in opposite directions from an inlet thereof spaced from the drive means by a portion of the piston second end surface and to positions respectively communicating with the first and second volumes, each first recess inlet sealingly covered by the housing member second end surface and each second recess inlet opening into the associated housing member opening in response to movement of the pistons in a direction tending to decrease the first volumes, thereby respectively sealing the first volumes from communication with fluid in the torque converter housing via the first recesses and communicating the second volumes with fluid in the torque converter housing via the second recesses, and each second recess inlet sealingly covered by the housing member second end surface and each first recess inlet opening into the associated housing member opening in response to movement of the pistons in a direction tending to decrease the second volumes, thereby respectively sealing the second volumes from communication with fluid in the torque converter housing via the second recesses and communicating the first volumes with fluid in the torque converter housing via the first recesses.