Abstract: A piezoelectric component with a monolithic stack, has electrode layers and piezoceramic layers arranged alternately one on top of the other, the piezoceramic layers have a piezoceramic, and having at least one porous security layer arranged in the stack for the formation of a crack if mechanical overload of the stack should occur. The piezoelectric component has an infiltration barrier arranged between the security layer and a lateral surface section of the stack for suppressing the penetration of a foreign substance into the security layer. The piezoelectric component can be as a piezoactuator for controlling a valve, particularly a valve of an internal combustion engine.

Abstract: An actuator for actuating a fuel injection valve has a piezoactuator, enclosed in an actuator housing unit (14, 16). The housing unit has a cylindrical actuator housing (14) which is elongate in its axial direction (A) and at least partially encased by an extruded plastic coat. The actuator housing unit (14, 16), in its encased area, is provided with a ventilation aperture (20) in which a ventilation element (22) produced from a microporous material is disposed.

Abstract: A protective cover for an actuating drive, that can be used as universally as possible, for components (14, 16) of a contacting and/or sealing arrangement of the actuating drive. The sealing arrangement is embodied in a liquid-tight but gas-permeable manner and ends in a cavity on the outer side, the cavity being covered by a cover (28) held on the actuating drive by means of a catch connection (30, 32).

Abstract: A piezoelectric component with a monolithic stack, has electrode layers and piezoceramic layers arranged alternately one on top of the other, the piezoceramic layers have a piezoceramic, and having at least one porous security layer arranged in the stack for the formation of a crack if mechanical overload of the stack should occur. The piezoelectric component has an infiltration barrier arranged between the security layer and a lateral surface section of the stack for suppressing the penetration of a foreign substance into the security layer. The piezoelectric component can be as a piezoactuator for controlling a valve, particularly a valve of an internal combustion engine.

Abstract: A method for creating a soldered joint to contacts of a piezoelectric actuator and polarizing the piezoceramic layers of the piezoelectric actuator has the steps of Polarization and soldering of the joint which are performed simultaneously such that the duration of the process is reduced.

Abstract: A fuel injector has a housing for an actuator (1), especially to a fuel injector with a connector of a contact stud support injection-molded thereto. The injector has a casing (10), disposed across at least part of the periphery of the actuator (1), and an actuator cover (20) placed on the casing (10). The actuator cover (20) is laser-welded to the casing (10) in an overlapping area (30) between the actuator cover (20) and the casing (10). According to a method for finishing the housing of a fuel injector having the aforementioned features, a laser beam used for a laser welding method is incident on the overlapping area (30) in a substantially perpendicular or substantially parallel orientation in relation to the axial direction (A) of the actuator (1) and laser-welds the actuator cover (20) to the casing (10).

Abstract: A protective cover for an actuating drive, that can be used as universally as possible, for components (14, 16) of a contacting and/or sealing arrangement of the actuating drive. The sealing arrangement is embodied in a liquid-tight but gas-permeable manner and ends in a cavity on the outer side, the cavity being covered by a cover (28) held on the actuating drive by means of a catch connection (30, 32).

Abstract: An actuator for actuating a fuel injection valve has a piezoactuator, enclosed in an actuator housing unit (14, 16). The housing unit has a cylindrical actuator housing (14) which is elongate in its axial direction (A) and at least partially encased by an extruded plastic coat. The actuator housing unit (14, 16), in its encased area, is provided with a ventilation aperture (20) in which a ventilation element (22) produced from a microporous material is disposed.

Abstract: A method is described for improving the long-term stability of a piezoelectric actuator encased in a potting compound containing or forming hydrogen atoms. Oxygen is contained in the piezoelectric actuator's piezoelectric ceramic. Appropriate means are employed so that unsaturated bonds of the hydrogen in the potting compound will release less oxygen from the piezoelectric ceramic. One means consists in reducing the concentration of hydrogen in the potting compound, with appropriate thermal processes as a result of which the concentration of hydrogen will be reduced to below a predefined threshold being applied after the piezoelectric actuator has been encased in the potting compound. Means that form bonds with the hydrogen in the potting compound or duct oxygen thereto are provided in further embodiments.

Abstract: A method is described for improving the long-term stability of a piezoelectric actuator encased in a potting compound containing or forming hydrogen atoms. Oxygen is contained in the piezoelectric actuator's piezoelectric ceramic. Appropriate means are employed so that unsaturated bonds of the hydrogen in the potting compound will release less oxygen from the piezoelectric ceramic. One means consists in reducing the concentration of hydrogen in the potting compound, with appropriate thermal processes as a result of which the concentration of hydrogen will be reduced to below a predefined threshold being applied after the piezoelectric actuator has been encased in the potting compound. Means that form bonds with the hydrogen in the potting compound or duct oxygen thereto are provided in further embodiments.

Abstract: A method for creating a soldered joint to contacts of a piezoelectric actuator and polarizing the piezoceramic layers of the piezoelectric actuator has the steps of Polarization and soldering of the joint which are performed simultaneously such that the duration of the process is reduced.