| 摘要 |
A piston can reciprocate in a piston guide cylinder in an axial direction and has a cavity on a piezo driver side thereof. If the piezo driver is energized, a tip of a projecting section of a pushing member pushes a bottom wall of the piston defining the cavity. If fuel pressure of a pressure control chamber increases via a pressurization chamber and a communication passage due to pressurization by the piston, a needle moves in a valve-opening direction against a first compression coil spring. Since the piston has the cavity, a movable mass of the piston is reduced while securing axial length of a sliding section. Thus, fuel leak from the sliding section between the piston and the piston guide cylinder can be suppressed, and an inertial resistance caused in the piston can be reduced. |
