Control element for injectors with switchable nozzle needle

The invention relates to a device for actuating a control piston or nozzle needle ( 27 ) via a control chamber ( 26 ). The control chamber communicates via a control chamber line ( 25 ) with valve chambers ( 3, 22 ) of a 3/2-way valve ( 5 ). The valve body ( 6, 40, 51 ) of this valve is switchable by means of an actuator ( 11 ). By means of a restoring spring ( 14 ), the valve body ( 6, 40, 51 ) is acted upon such that a seat portion ( 7 ), embodied in the housing ( 4 ) on the valve body ( 6, 40, 51 ), is put into its valve seat ( 20 ). The valve body ( 6, 40, 51 ) of the 3/2-way valve ( 5 ) has a seat portion ( 7 ) and a longitudinal slide portion ( 8 ), as well as hydraulic faces ( 31,32 ), facing one another, that make the state of pressure equilibrium of the valve body ( 6, 40, 51 ) possible. The valve body ( 6, 40, 51 ) is moved to different stroke lengths ( 10; 23, 24 ) by means of an actuator ( 11 ).