Fuel injection valve for internal combustion engine

摘要

In a fuel injection valve, it is intended to enhance valve-closing responsivity while maintaining durability (anti wear property) of a collision portion between a stationary core and a movable core and valve-opening responsivity.;An annular end face 106A of the movable core 106 in the fuel injection valve is provided with a collision portion 106C that collides to a stationary core 107 when the movable core is magnetically attracted toward the stationary core side and a non-collision portion that keeps a fluid gap between both cores at an area of an outer side or an inner side from the collision portion. The annular end faces of the stationary core and the movable core are coated with platings 30, 31 having anti wear property, and at least one of the platings of the stationary core and the movable core is formed in such a manner that the thickness thereof at the collision portion 106C is to be thicker and the thickness thereof at the non-collision portion is to be thinner.

主权项

1. A fuel injection valve for an internal combustion engine comprising an electromagnetic coil, a movable valve element, a stationary core, a movable core, and a spring, wherein the stationary core and the movable core are disposed in a moving direction of the movable valve element so that annular end faces of the stationary core and the movable core are opposed to each other with a predetermined gap when the electromagnetic coil is not energized, by the spring applying a spring load to the movable core in a closing-direction of the movable valve element, and the movable core is magnetically attracted toward the stationary core against force of the spring when the electromagnetic coil is energized, thereby to open the fuel injection valve, wherein
the annular end faces of the stationary core and the movable core are provided respectively with collision portions that collide to each other when the movable core is magnetically attracted toward the stationary core and non-collision portions for keeping a fluid gap at areas outside or inside from the collision portions, at least one of the annular end faces of the stationary core and the movable core is comprised of an annular flat face formed at its non-collision portion and an annular protuberance formed at its collision portion so as to be higher than the annular flat face, the annular end faces of the stationary core and the movable core are coated respectively with platings having anti wear property, at least one of the platings of the stationary core and the movable core is formed in such a manner that a first thickness thereof over the annular protuberance of the collision portion is thicker than a second thickness thereof over the annular flat face of the non-collision portion, a relationship of the fluid gap and the annular protuberance is set so that the fluid gap is greater than a height of the annular protuberance, and the first thickness of the at least one of the platings is positioned closer to the movable valve element than the second thickness of the at least one of the platings.