Electronically controlled butterfly valve provided with a flat leaf spring and a spiral spring to establish the limp-home position

An electronically controlled butterfly valve (1) comprising a valve body (2), a valve seat (4) formed in the valve body (2), a butterfly disc (5) adapted to engage the valve seat (4), a shaft (6) on which the butterfly disc (5) is keyed, an electric motor (3) coupled to the shaft (6) by means of a gear transmission (8) having a final gear (18) keyed on the shaft (6) in order to rotate the butterfly disc (5) between a position of maximum opening and a closed position of the valve seat (4), a spiral return spring (35) adapted to rotate the butterfly disc (5) towards the closed position, and an opposing spring (36) adapted to rotate the butterfly disc (5) towards a partially open or limp-home position defined by an abutment body (37) against the action of the return spring (35), the butterfly valve (1) being characterised in that the opposing spring (36) is a flat leaf spring and is mounted on a moving member (39) which is mounted coaxially and idly on the shaft (6) and has a projection (47) adapted to engage in abutment against the abutment body (37), an end (44) of the opposing spring (36) being free and ending in a projection (45) which is disposed so as to be superimposed on the trajectory followed by a member (46) rigid with the final gear (18).