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

Described herein is an on-board centralized system for regulating the pressure of the tyres of a motor-vehicle. The system comprises a source of pressurized air (IO l ), a circuit that sets in communication the source of pressurized air (I O l) with a plenum (P, PR) of each wheel (W, WR), a solenoid valve (102) for opening or closing said communication, and means for connection of the plenum (P, PR) of each wheel (W, WR) to the inner chamber (C) of the respective tyre. The aforesaid connection means comprise a first connection line (L2) and a second connection line (L3), set in parallel to one another, for deflation and inflation, respectively, of the tyre, and a first one-way valve (28) and a second one-way valve (32) interposed, respectively, in the first and second connection lines (L2, L3) to allow only a flow of air respectively from and to the inner chamber (C) of the tyre. Furthermore, associated to the first one-way valve (28) is a return spring (30) having a pre-set load, in such a way as to isolate the inner chamber (C) of the tyre of each wheel (W, WR) from the part of the circuit upstream of the one-way valve (28) when said upstream part of the circuit is at atmospheric pressure, and in such a way as to guarantee a pre-set minimum value of the pressure of the inner chamber (C) of the tyre when the part of the circuit upstream of the one-way valve (28) is at a pressure lower than atmospheric pressure.