Hydrokinetic coupling apparatus with locking clutch for motor vehicle

Hydrokinetic coupling appliance, having an input element (10), in the form of a casing, able to be made integral with respect to rotation with a driving shaft and provided with an axially fixed transverse wall (11), an output element (5) in the form of a hub, a centering device (21) having a blind hole (120) at a center and being integral with the transverse wall (11) whilst being interposed axially between the latter and the hub (5), a piston (20) mounted at an internal periphery so as to be axially movable with respect to the transverse wall (11) whilst being connected to said wall (11) with respect to rotation, at least one friction lining (22) able to be clamped disengageably between the external periphery of the piston (20) and the transverse wall (11), and means for fixing the friction lining (22) to the hub (5), characterized in that, the hub (5) having an internally fluted socket (50) for connecting the hub (5) with a driven shaft (201) with respect to rotation, the said socket (50) enters inside the blind hole (120) in the centering device (21), in that the hub (5) has, parallel to said socket (50) and radially above said socket (50), an axially oriented annular rim (52) whose external periphery constitutes a guide surface (59) for the piston (20), and in that a sealing joint (56) acts between the rim (52) and the piston (20).