Hydrokinetic torque coupling device with centered lock-up clutch

A hydrokinetic torque-coupling device for coupling together a driving shaft and a driven shaft rotatable about a rotational axis, comprising:

• an impeller wheel, a turbine wheel and a stator interposed axially between the impeller wheel and the turbine wheel;
• a casing including a cover shell, an impeller shell non-moveably secured to the cover shell, and a center hub non-moveably attached to the cover shell of the casing;
• a hollow stationary stator shaft operatively coupled to the stator, the driven shaft axially extending through the stationary stator shaft;
• a first hydraulic fluid passage formed axially through the driven shaft;
• a second hydraulic fluid passage formed radially between the stationary stator shaft and the driven shaft;
• a third hydraulic fluid passage formed radially adjacent to the stationary stator shaft and radially spaced from the second hydraulic fluid passage;
• an impeller hub unitary with the impeller shell and coaxial to the rotational axis an annular bushing disposed radially between the impeller hub and the stationary stator shaft;
• a generally cylindrical sleeve non-moveably secured to the stationary stator shaft and radially spaced therefrom so as to define the third hydraulic fluid passage between the sleeve and the stationary stator shaft;
• and
• a lock-up clutch interconnecting the turbine wheel and the casing, the lock-up clutch including
• a piston housing member non-moveably attached to the center hub;
• a lockup piston axially movable relative to the piston housing member along the center hub toward and away from the cover shell to position the hydrokinetic torque coupling device into and out of a lockup mode;
• a friction device disposed axially between the lockup piston and the cover shell;
• a first hydraulic chamber defined between the lockup piston and the piston housing member;
• and
• a second hydraulic chamber defined between the lockup piston and the cover shell;
• the center hub having a first hydraulic channel hydraulically connected to the first hydraulic chamber and a second hydraulic channel hydraulically connected to the second hydraulic chamber so as to operate the lockup clutch;
• the first hydraulic fluid passage hydraulically connected to the first hydraulic chamber through the first hydraulic channel, the second hydraulic fluid passage hydraulically connected to the second hydraulic chamber through the second hydraulic channel, and the third hydraulic fluid passage hydraulically connected to a torus chamber defined between the impeller wheel and the turbine wheel;
• the stationary stator shaft having at least one hydraulic channel extending generally radially therethrough and fluidly connecting the third hydraulic fluid passage with an annular cavity located radially between the impeller hub and the stator shaft.