Modular actuator unit for a fuel injection valve
View Patent ↗An actuator unit for a fuel injection valve of a vehicle internal combustion engine. The actuator unit includes an electronic component formed as a stack. The component includes a plurality of electrode layers and a plurality of material layers which are arranged alternately and react to the application of an electric field. The component also has two outer electrodes electrically connected to respective electrode layers on at least one circumferential side of the component. Additionally, the actuator unit has a piezoelectric sensor coupled to the component in a force-fitting manner, in the stroke direction of the component. When the component is in operation, the sensor detects a force generated by the component, as a voltage or charge between two electrodes arranged on opposing end faces, of a sensor element. The electrodes are deposited from an electrically conductive material directly onto at least the end faces of the sensor element.
1. An actuator unit for an injection valve of an internal combustion engine of a vehicle, comprising:
an electronic component in the form of a stack, with
a plurality of inner stack electrode layers;
a plurality of layers of material that react to the application of an electric field, wherein layers of material and the inner stack electrode layers are stacked alternately; and
two outer stack electrodes, to which the inner stack electrode layers are each alternately electrically connected on at least one peripheral side of the component;
a piezoelectric sensor comprising a sensor body and two outer sensor electrodes disposed on opposite end faces of the sensor body,
wherein one of the two outer sensor electrodes of the piezoelectric sensor is coupled to the component through an insulation layer in a force-fit manner in the stroke direction of the component, and the piezoelectric sensor detects a force generated and applied to the one of the two outer sensor electrodes by movement of the component during operation of the component, the force applied to the one of the two outer sensor electrodes being detected as a voltage or charge between the two outer sensor electrodes,
wherein the two outer sensor electrodes are comprised of electrically conductive material deposited directly onto at least one of the end faces of the sensor body.
2. The actuator unit as claimed in claim 1 , in which a respective end face of the sensor body is bounded by side edges, wherein the electrode disposed on the respective end face is spaced apart from at least one of the associated side edges by a spacing.
3. The actuator unit as claimed in claim 1 , in which the electrodes are produced by plasma deposition or sputtering or vapor deposition.
4. The actuator unit as claimed in claim 1 , in which the sensor is connected to the component in a force-fit manner by an insulation layer.
5. The actuator unit as claimed in claim 1 , in which at least one contacting segment of a respective electrode is disposed on at least one lateral surface of the sensor body, wherein the at least one contacting segment and the associated electrode are produced over a side edge in one step.
6. The actuator unit as claimed in claim 5 , in which at least on a side edge opposite the contacting segment the spacing is provided between the electrode and said side edge.
7. The actuator unit as claimed in claim 1 , in which the sensor body is a monolithic plate made of a piezo ceramic.
8. The actuator unit as claimed in claim 7 , in which the piezo ceramic of the sensor is made of a different material from the layers of material of the component.
9. The actuator unit as claimed in claim 1 , in which the electrodes have a layer thickness of less than 20 μm.
10. The actuator unit as claimed in 2 , in which the electrodes have a layer thickness of less than 10 μm.
11. The actuator unit as claimed in claim 9 , in which a respective end face of the sensor body is bounded by side edges, wherein the electrode disposed on the respective end face is spaced apart from at least one of the associated side edges by a spacing.