Patent ID: 8672652
Filing Date: 2014-03-18
Classification: B23K,F02M,F04B

Abstract:
1. A high-pressure fuel supply pump, comprising: a pump housing with a recess formed therein to form a pressurizing chamber; a first cylindrical surface formed on an inner wall of the recess; a cylinder having, on its outer surface, a second cylindrical surface fitted into the first cylindrical surface, and at a central section, a through-hole with one end thereof apertured toward the pressurizing chamber; a piston plunger that takes a fluid into the pressurizing chamber by repeating reciprocation under a slidingly fitted condition in the through-hole, and discharges the fluid from the pressurizing chamber under pressure; and a welded connection that maintains the pump housing and the cylinder in a fitting-in state of the housing and cylinder, thereby to prevent both from sliding out from each other; wherein: the welded connection forms an alloyed diffusion zone inclined to a central axis of the cylinder and interposed between a first metal of which the pump housing is formed and a second metal of which the cylinder is formed to permit joinder of dissimilar first and second metals; and plastic flow zones of metals of the pump housing and the cylinder are formed at opposed ends of the alloyed diffusion zone so that the alloyed diffusion zone is sandwiched between the plastic flow zones.