On-board centralized system for regulating the pressure of the tyres of a motor-vehicle

An on-board centralized system for regulating pressure of tyres of a motor-vehicle having at least two, steering or non-steering, driving wheels, wherein each driving wheel is rigidly connected to a wheel spindle, which is rotatably supported on a wheel support and is connected in rotation to a respective axle shaft via a constant-velocity joint having an input member connected in rotation to said axle shaft and an output member rigidly connected to said wheel spindle, said system comprising:

• a source of pressurized air;
• pneumatic rotary joints, each associated to a respective driving wheel;
• and
• a circuit, which sets in communication the source of pressurized air with an inlet fitting of said pneumatic rotary joint, said circuit including a solenoid valve for opening or closing said communication,
• wherein said output member of the constant-velocity joint and said wheel spindle have an internal duct for passage of air, and
• wherein said internal duct has a first end that gives out onto an outer surface of said output member of the constant-velocity joint and is connected by a flexible hose to an outlet fitting of the pneumatic rotary joint, and a second end that gives out onto an end surface of the wheel spindle and communicates with a plenum of the respective driving wheel;
• and
• means for connecting said plenum of the driving wheel with the inner chamber of the respective tyre.