Patent ID: 7665976

Claim:
A high pressure fuel pump, comprising: a pump housing; a cylinder fitted to the pump housing; a plunger slidably fitted in the cylinder; a seal unit comprised of a first seal configured to prevent fuel leaked from an end of a sliding portion between said cylinder and said plunger from leaking out to atmosphere, a second seal axially spaced along said plunger from said first seal to prevent a lubricant oil for a driving mechanism of said plunger from entering into said cylinder from said end of the sliding portion of said cylinder and said plunger and a seal holder for said first and second seals; a holder configured to hold the seal unit around the plunger and provided with a stepped seal holding portion for fixing said seal holder therein, wherein an outer circumference of said holder is fixed to an inner circumference of said pump housing, and said seal unit is held between an inner circumference of said holder and said plunger and between said seal holder and said stepped seal holding portion so as to constitute a unit, and an outer diameter of said cylinder is smaller than that of said holder.