Hydrokinetic torque converter with lockup clutch

A hydrokinetic torque converter comprising:

• a housing having a fluid-containing chamber and being rotatable about a predetermined axis;
• a pump, a turbine and a stator in said chamber;
• and
• an engageable and disengageable lockup clutch interposed between said housing and said turbine and comprising a piston movable in said chamber in the direction of said axis and dividing said chamber into a first compartment disposed at a first radial distance from said axis and a second compartment wherein the pressure of fluid varies when the converter is in use, at least one first friction surface carried by said piston and at least one second friction surface carried by a component rotatable with said housing, said friction surfaces confronting and being in engagement with each other in the engaged condition of said clutch and being disposed at a greater second radial distance from said axis, at least one of said piston and said component having at least one passage for the flow of fluid from said second compartment into said first compartment along said friction surfaces in the engaged condition of said clutch, at least one of said piston and said component being elastically deformable at said at least one passage and said at least one passage being configurated to permit variations of the rate of fluid flow therein as a function of variable fluid pressure in said second compartment and the elastic deformability of said at least one of said piston and said component.