Fuel injector for internal combustion engines

A fuel injector for internal combustion engines, comprising an injector body provided with fuel injection ports, a needle valve adapted to be lifted in said injector body and open said injection ports, a control piston joined to said needle valve and adapted to control a sliding movement of said needle valve, a fuel chamber formed in said injector body so as to store a fuel therein, a return spring provided in said fuel chamber and adapted to urge said needle valve in said fuel port closing direction, a piezoelectric element adapted to be displaced in accordance with voltage variation so as to control the lift of said control piston, and a displacement increasing mechanism adapted to increase the displacement of said piezoelectric element so as to lift said needle valve, and transmit the resultant displacement to said control piston,

• wherein said displacement increasing mechanism comprises a pressure member fixed to said piezoelectric element and provided on its outer circumferential surface with projecting portions having points of application of a displacement force, a hollow support member fixed in the interior of said injector body provided with fulcrum projecting portions, a lift member provided liftably in a hollow portion of said support member, and a disc spring set between said pressure member and said support member with an inner circumferential end portion thereof engaged with said lift member.