Patent ID: 8556602

Claim:
A fuel pump for a direct injection system comprising: at least one pumping chamber; a piston slidingly mounted inside the pumping chamber to cyclically vary a volume of the pumping chamber; an intake duct connected to the pumping chamber and regulated by an inlet valve; a delivery duct connected to the pumping chamber and regulated by a one-way valve allowing only outgoing-fuel flow from the pumping chamber; a seat arranged below the pumping chamber around a lower portion of the piston; an annular seal housed in the seat and preventing fuel leakage along a side wall of the piston; and an annular element delimiting, on an upper side thereof, the seat housing the seal such that an axial dimension of the seat is not greater than an axial dimension of the seal to prevent the seal from axially “shaking” inside the seat as a consequence of cyclic axial movement of the piston, wherein the annular element defines a lower limit of travel of the piston and a shoulder of the piston rests on the annular element, preventing further descent of the piston, the annular element has a lower edge that, on one side, forms the lower limit of travel of the piston and, on another side, forms an upper boundary of the seat housing the seal, and the lower edge of the annular element has a U-shaped cross-section so as to provide a certain elastic deformability.