Fuel injector and relative production method

A fuel injector comprising:

• a tubular injector body (3) including a wall (9) having a receiving hole (15);
• a high-pressure fuel supply conduit (7) comprising a ring-shaped end portion (24);
• a fitting (6) fixed along said wall (9) at said receiving hole (15) for connecting said supply conduit (7) to said injector body (3) through said receiving hole (15);
• said fitting (6) comprising:
• a threaded sleeve (19) having a housing hole (22) for housing said supply conduit (7) and gripping said ring-shaped end portion (24) between the injector body (3) and said sleeve (19);
• said housing hole (22) being smaller in diameter than said ring-shaped end portion (24);
• an attachment (18) having a threaded hole (21) aligned with said receiving hole (15) to connect said sleeve (19) to said attachment (18);
• a ring (17) integral with said attachment (18);
• wherein said wall has a flared portion (16) extending from said receiving hole (15), and said sleeve (19) has an opposing flared portion (23) extending from said housing hole (22) and facing said flared portion (16) of said receiving hole (15);
• said flared portion (16) of said wall (9) and flared portion (23) of said sleeve (19) flaring in opposite directions and bearing against opposite flared surfaces of said ring-shaped end portion of said supply conduit (7) so that when said sleeve (19) is threadably advanced in said attachment (18), said ring-shaped end portion (24) is deformed between said flared portion (16) of said wall (9) and said flared portion (23) of said sleeve (19) to provide hermetic sealing between said supply conduit (7) and said injector body (3).