FUEL PUMP FOR A DIRECT INJECTION SYSTEM WITH AN IMPROVED HYDRAULIC SEALING OF THE INTAKE VALVE

A fuel pump (4) for a direct injection system (1) having: a pumping chamber (14); a piston (15), which is mounted in a sliding manner on the inside of the pumping chamber (14); an intake channel (17), which originates from a wall of the pumping chamber (14) and has a housing portion (28); an intake valve (18), which is inserted into the housing portion (28) of the intake channel (17); and a locking ring nut (30) with an annular shape, which is threaded and is screwed into the housing portion (28) of the intake channel (17) so as to strike against the intake valve (18); the housing portion (28) has an annular abutment (29), which reduces the diameter of the housing portion (28) and against which the intake valve (18) strikes; the locking ring nut (30) is screwed into the housing portion (28) with a tightening force that is sufficient to determine a plastic deformation of the annular abutment (29) against the intake valve (18).