Patent ID: 9151290
Filing Date: 2015-10-06
Classification: B23P,F02M,F04B,Y10T

Abstract:
1. A fuel supply pump comprising: a plunger that is adapted to reciprocate in an axial direction thereof; and a housing that includes a cylinder hole, in which the plunger is axially slidably received, wherein: one axial end portion of the cylinder hole is fluid-tightly closed by the plunger to form a pressurizing chamber therein; the plunger is adapted to reciprocate and slide in the axial direction in the cylinder hole to change a volume of the pressurizing chamber and thereby to draw fuel into the pressurizing chamber and then discharge the fuel from the pressurizing chamber upon pressurization of the fuel in the pressurizing chamber; a discharge flow passage is connected to the pressurizing chamber at the housing and is adapted to guide and discharge the pressurized fuel from the pressurizing chamber to an outside of the fuel supply pump; a connection opening of the discharge flow passage opens to the pressurizing chamber and is formed in a hole wall of the cylinder hole, which forms the pressurizing chamber; a prestressed area is formed in the hole wall of the cylinder hole and a passage wall of the discharge flow passage such that the prestressed area includes an inner peripheral edge of the connection opening and has a residual compression stress generated by a pressure that is applied through autofrettage; a check valve is placed in the discharge flow passage to limit a backflow of the fuel into the pressurizing chamber; the check valve opens to conduct the pressurized fuel from the pressurizing chamber to the outside of the fuel supply pump through the discharge flow passage when a fuel pressure of the pressurized fuel in the pressurizing chamber becomes larger than predetermined valve opening pressure; a seat, relative to which a valve element of the check valve is adapted to be seated and lifted, is formed in the passage wall of the discharge flow passage; and a pressure applying area, to which the pressure is applied through the autofrettage to form the prestressed area, does not reach to the seat in the passage wall of the discharge flow passage.