Hydrokinetic torque coupling device having turbine-piston lockup clutch, and related methods

A hydrokinetic torque coupling device for coupling together a driving shaft and a driven shaft, the torque coupling device comprising:

• an impeller rotatable about a rotational axis and comprising an impeller shell;
• a casing comprising the impeller shell and a casing shell fixedly connected to so as to be non-rotatable relative to the impeller shell, the casing having a first engagement surface;
• a turbine-piston hydrodynamically drivable by the impeller and comprising a turbine-piston shell having a second engagement surface facing the first engagement surface, the turbine-piston being axially displaceable relative to the impeller between a hydrodynamic transmission mode in which the first and second engagement surfaces are spaced from and not frictionally engaged with one another, and a lockup mode in which the first and second engagement surfaces are frictionally engaged with one another to mechanically lock the turbine-piston with the casing so as to be non-rotatable relative to the casing;
• a stator situated between the impeller and the turbine-piston;
• a biasing device configured to exert an axial load against the turbine-piston to urge the turbine-piston axially away from the lockup mode and towards the hydrodynamic transmission mode, wherein the axial load exerted by the biasing device decreases as the turbine-piston moves axially towards the lockup mode and increases as the turbine-piston moves axially away from the lockup mode;
• an output hub;
• and
• a damper assembly interconnecting the turbine-piston to the output hub.

A method of assembling a hydrokinetic torque coupling device for coupling a driving shaft and a driven shaft together, comprising:

• providing a torque converter rotatable about a rotational axis and comprising
• an impeller comprising an impeller shell;
• a turbine-piston hydrodynamically drivable by the impeller and comprising a turbine-piston shell;
• and
• a biasing device;
• and
• operatively connecting a casing shell to the impeller shell of the torque converter to form a casing that is rotatable about the rotational axis and has a first engagement surface, the turbine-piston having a second engagement surface and being axially displaceable relative to the impeller between a hydrodynamic transmission mode in which the first and second engagement surfaces are spaced from and not frictionally engaged with one another, and a lockup mode in which the first and second engagement surfaces are frictionally engaged with one another to mechanically lock the turbine-piston with the casing so as to be non-rotatable relative to the casing,
• wherein the biasing device is configured to exert an axial load against the turbine-piston to urge the turbine-piston axially away from the lockup mode and towards the hydrodynamic transmission mode, wherein the axial load exerted by the biasing device decreases as the turbine-piston moves axially towards the lockup mode and increases as the turbine-piston moves axially towards the hydrodynamic transmission mode.