Variable-diameter wheel

Variable-diameter wheel comprising:

• at least one rim or hub having a predefined diameter, to which at least one drive axle of the wheel is connected;
• at least one outer surface, external to the hub, having an outer diameter greater than the predefined diameter of said hub;
• the wheel is applied to a vehicle in which the outer diameter of the outer surface of said wheel is defined by at least one tread of at least one tire mounted on said hub;
• the wheel comprises at least one diameter variation mechanism secured to said axle and adapted to vary an actual diameter of said wheel in response to variation in torque applied to the drive axle by at least one propulsion system;
• the diameter variation mechanism is passive and can take at least two operating configurations:
• an idle configuration, in which said diameter variation mechanism is substantially incorporated within the outer diameter of the outer surface of the wheel;
• an active configuration, in which said diameter variation mechanism increases the actual diameter of the wheel by bringing at least a portion of said diameter variation mechanism beyond the outer diameter of the outer surface of the wheel;
• wherein a variation in the torque applied to the axle due to the wheel being obstructed or blocked by an obstacle brings the diameter-variation mechanism into the active operating configuration.