Accumulator fuel injection device

Abstract

In an accumulator fuel injection device, a valve member of a solenoid valve includes a shaft and a spherical member. The spherical member is slidably supported at the tip portion of the shaft. The spherical member is prevented from falling off by caulking the tip of the shaft. A flat plate working as a valve seat for the spherical member is provided so that the spherical member allows communication between a pressure control chamber and a low-pressure side when separated from the flat plate, while prohibiting the communication therebetween when seated on the flat plate. On the other hand, the flat plate is formed with fuel relief passages in a tight contact region between the flat plate and the spherical member. The fuel relief passages communicate with the low-pressure side even when the spherical member is seated on the flat plate. Thus, a hydraulic force applied to the spherical member in a solenoid valve opening direction when the spherical member is seated on the flat plate, is rendered smaller. Accordingly, a biasing force of a spring urging the valve member in a solenoid valve closing direction can be set smaller, and thus, a magnetic force of the solenoid valve for lifting the valve member against the biasing force of the spring can also be set smaller. The fuel relief passages may be provided on the spherical member.