Valve assembly for an injection valve and injection valve

An injection valve comprising:

• a valve body having a longitudinal axis and a cavity with a fluid inlet portion and a fluid outlet portion;
• a valve needle axially moveable in the cavity to prevent a fluid flow through the fluid outlet portion in a closing position and releasing the fluid flow through the fluid outlet portion in further positions;
• the valve needle comprising a needle shaft, an upper retaining element and a lower retaining element both fixedly connected to the needle shaft;
• the upper retaining element extending in a radial direction and disposed in a first axial region of the valve needle facing away from the fluid outlet portion;
• the lower retaining element extending in the radial direction and arranged in a second axial region of the valve needle facing the fluid outlet portion;
• an electro-magnetic actuator unit to actuate the valve needle, the electro-magnetic actuator unit comprising a pole piece and an armature spaced from the pole piece by a first axial gap when the electro-magnetic actuator unit is de-energized;
• the armature axially movable in the cavity and joined to the valve needle by form-fit;
• the armature sliding on the valve needle between the upper retaining element and the lower retaining element;
• a calibration spring preloaded to bias the valve needle towards the closing position;
• and
• a spring element arranged between the armature and the upper retaining element which biases the armature towards the lower retaining element;
• wherein the spring element and the calibration spring are adapted to one another such that the armature compresses the spring element and travels at least 50% but no more than 70% of the first axial gap before an opening force for displacing the valve needle away from the closing position becomes larger than a total needle closing force, thereby initiating a displacement of the valve needle away from the closing position before the armature comes into contact with the pole piece;
• the opening force for displacing the valve needle away from the closing position is transferred from the armature to the valve needle completely through the spring element throughout a full range of axial displacement of the armature during the operation of the valve assembly;
• and
• the armature and the upper retaining element remain spaced apart from each other throughout the full range of axial displacement of the armature during the operation of the valve assembly.