HIGH PRESSURE FUEL PUMP
A high pressure fuel pump according to the present invention includes a cylinder which is fitted in a concave portion formed in a pump housing and which defines a compression chamber of the pump and a plunger which pressurizes, by sliding against the cylinder, the fluid in the compression chamber. The high pressure fuel pump is structured such that the fluid sucked into the compression chamber by reciprocating motion of the plunger is pressurized and is then discharged from the compression chamber. The cylinder is formed of a cylindrical member which has a ceiling portion and in which the compression chamber is partitionedly formed. A fuel suction path formed in the pump housing reaches the compression chamber through the cylinder and a fuel discharge path formed in the pump housing is connected to the compression chamber through the cylinder. The cylinder is pressed, for sealed fixation, against the pump body by a fuel pressurizing force applied to the cylinder. Neither holder nor caulking is used for cylinder fixation.
1 - 10 . (canceled)
11 . A high-pressure fuel supply pump comprising:
a cylinder having a ceiling portion and a cylindrical portion;
a plunger sliding with a sliding portion formed on an inner peripheral surface of the cylindrical portion;
a pump housing having an insertion hole through which the cylinder is inserted,
the cylinder has a through hole formed in the cylindrical portion, and is press-fitted in the insertion hole so that the ceiling portion is a downstream side in a press-fitting direction,
wherein
the cylinder has a first press-fitting portion formed on an outer peripheral surface of the ceiling portion in contact with an inner peripheral surface of the insertion hole and a second press-fitting portion formed on an outer peripheral surface of the cylindrical portion in contact with the inner peripheral surface of the insertion hole,
the second press-fitting portion is located closer to the through hole than an opening end of the cylinder into which the plunger is inserted, and
a radial gap between the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the insertion hole is provided on an upstream side in the press-fitting direction from the second press-fitting portion.
12 . The high-pressure fuel supply pump according to claim 11 ,
wherein the cylinder has an enlarged portion having an inner diameter larger than the sliding portion, the enlarged portion formed between the sliding portion and the ceiling portion.
13 . The high-pressure fuel supply pump according to claim 11 ,
wherein the plunger has a large diameter portion and a small diameter portion smaller than the large diameter portion, and
wherein the pump housing is formed with a flow path through which fuel contacts the small diameter portion of the plunger.
14 . The high-pressure fuel supply pump according to claim 11 ,
the insertion hole communicates with a low pressure fuel chamber and is closed by the ceiling portion.