An oil transfer unit has a rotating part, a stationary part provided with an oil mouth, and a floating part having a support body coupled to the stationary part; the floating part has an annular pad, that is distinct from the body and is provided with a cylindrical surface fitted onto an outer cylindrical surface of the rotating part in a non-contact configuration, with an annular groove provided between the pad and the rotating part to put the oil mouth into communication with an inner chamber of the rotating part; both sides of the groove are sealed by a hydrostatic seal between the cylindrical surfaces; an angular retaining constraint is provided to retain angularly the pad with respect to the body; at least one element is breakable or plastically deformable to release the angular constraint when the torque transferred to the body, in use, exceeds a defined threshold.