Air filter for internal combustion engine

A filter for filtering combustion air of an internal combustion engine, said filter comprising a case having a generally cup-shaped body (1) with a base and a wall extending from said base, and a cover (10) which caps said body, said base having a raised portion (3) surrounded by an annular groove (5) and a pipe (6) which constitutes an inlet opening of the filter, said pipe opening onto said annular groove tangentially of said annular groove, said case defining a filtering chamber provided with openings including the inlet opening (6) and an outlet opening (4) arranged coaxially in the base, a generally cylindrically shaped filter cartridge (9) with open opposite ends and of a flexible material through which cartridge said openings communicate with each other, and means for supporting said cartridge so that it preserves the integrity of its shape, said supporting means comprising a ring arrangement of a series of parallel rods (8) with respect to which rods said cartridge is supported, said rods being disposed about a circle extending around the outlet opening of the case said circle being coaxial with said outlet opening, said rods being integrally moulded with said case, said rods being free relative to each other at one end thereof.