Abstract: A piezo-stack includes a plurality of lateral surfaces and a first passivation layer applied to a first lateral surface. The first passivation layer terminates flush with opposing lateral surfaces that adjoin the first lateral surface.

Abstract: A method for producing a piezo actuator includes: providing a green stack including alternately successive green films and inner electrode layers; forming trenches on the outside green stack in areas in which the inner electrode layers are intended to be electrically insulated from the corresponding outer electrodes, the trenches shortening the inner electrode layers from the outside of the green stack toward the inside; filling the trenches with an electrically insulating slurry; further processing the green stack, including filling the trenches with slurry, such that the green films produce piezo electric layers and the green stack produces a piezo stack; mounting two outer electrodes on the outside of the piezo stack, such that the two outer electrodes are alternately electrically connected to the inner electrode layers. The trenches may be filled with the slurry using one of the following methods; screen printing, immersion, spraying, or vacuum infiltration.

Abstract: A piezo-stack includes a plurality of lateral surfaces and a first passivation layer applied to a first lateral surface. The first passivation layer terminates flush with opposing lateral surfaces that adjoin the first lateral surface.

Abstract: A piezoceramic multilayer actuator has a first sub-stack (12, 14, 16) with a plurality of piezoceramic layers (22) and at least one internal electrode (24, 26), the piezoceramic layers (22) and the at least one internal electrode (24, 26) being laminated in an alternating manner, a second sub-stack (12, 14, 16) has a plurality of piezoceramic layers (22) and at least one internal electrode (24, 26), the piezoceramic layers (22) and the at least one internal electrode (24, 26) being laminated in an alternating manner, and a connection layer (40) arranged between the first sub-stack (12, 14, 16) and the second sub-stack (12, 14, 16), wherein the connection layer (40) is set up by a multitude of single connection points or connection lines (44) or other connection regions.

Abstract: A piezoelectric component, e.g., for use as an actuator of a fuel injection valve in a motor vehicle, may include a stack-shaped actuator body including a plurality of piezoelectric elements and inner electrode layers arranged in an alternating manner in a stacking direction, each inner electrode layer being connected alternately to one of two metalizations on an outer face of the stack in an electrically conductive manner. Each metalization is connected to an electrically conductive electrode structure via an electrically conductive contacting element (e.g., adhesive or solder). The stack-shaped actuator body has at least one predetermined breaking point, and the metalizations and/or the contacting elements have a recess in the region of the at least one predetermined breaking point.

Abstract: A piezoelectric component with a monolithic stack has piezoceramic layers and electrode layers arranged alternately one on top of the other, at least one porous security layer arranged in the stack for the formation of a crack if mechanical overload of the stack occurs, at least one outer electrode arranged at a lateral surface section for electric contacting of the electrode layers and a plastic sheath of the stack for protecting the stack, wherein the plastic sheath has silicon. The piezoelectric component is characterized in that a coating of the outer electrode, has silicon-free polymer, is arranged between the outer electrode and the plastic sheath. By coating the plating of the outer electrode, the area of the security layer present directly under the plating is protected from silicon component deposits. The piezoelectric component is used for the control of valves, particularly of injection valves of internal combustion engines.

Abstract: A method for producing a piezo actuator includes: providing a green stack including alternately successive green films and inner electrode layers; forming trenches on the outside green stack in areas in which the inner electrode layers are intended to be electrically insulated from the corresponding outer electrodes, the trenches shortening the inner electrode layers from the outside of the green stack toward the inside; filling the trenches with an electrically insulating slurry; further processing the green stack, including filling the trenches with slurry, such that the green films produce piezo electric layers and the green stack produces a piezo stack; mounting two outer electrodes on the outside of the piezo stack, such that the two outer electrodes are alternately electrically connected to the inner electrode layers. The trenches may be filled with the slurry using one of the following methods; screen printing, immersion, spraying, or vacuum infiltration.

Abstract: A piezoelectric actuator unit which undergoes less change in the amount of displacement and shows high durability in continuous operation under a high voltage and a high pressure over a long period of time is provided. The piezoelectric actuator unit including a multi-layer piezoelectric element having piezoelectric layers and metal layers with the piezoelectric layers and the metal layers being stacked one on another, and a case which houses the multi-layer piezoelectric element, wherein at least one of the plurality of metal layers is stress relieving layer which consists of a plurality of partial metal layers that are scattered throughout the entire region between two piezoelectric layers which adjoin the partial metal layers in the direction of stacking, and voids, and a peel-off section is formed at least in a part of the interface between the stress relieving layer and the piezoelectric layer that adjoins therewith.

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 multi-layer piezoelectric element includes a stack having metal layers and piezoelectric layers stacked one on another, and a pair of external electrodes formed on the side faces of the stack. At least one of the metal layers is a stress relieving layer having partial metal layers scattered between the two piezoelectric layers and voids. Junction sections are formed between the two piezoelectric layers to join and are disposed on both sides of an imaginary straight line drawn to connect the center of width of one of the external electrodes and the center of width of the other of the external electrodes in a plane including the stress relieving perpendicular to the stacking direction.

Abstract: A multi-layer piezoelectric element having higher durability which experience less decrease in the amount of displacement even when operated continuously over a long period of time under a high pressure and a high voltage is provided. The multi-layer piezoelectric element comprises a plurality of piezoelectric layers and a plurality of internal electrode layers, wherein the piezoelectric layers and the internal electrode layers are stacked alternately one on another, and at least one of the plurality of internal electrode layers contains at least one nitride, titanium nitride or zirconium nitride.

Abstract: A piezoelectric stack (1) has alternately successive piezoelectric layers (2) and inner electrode layers (3, 4) which are alternately electrically connected to two outer electrodes (7, 8) which are arranged on the outer side (5, 6) of the piezoelectric stack (1). The piezoelectric stack (1) also has at least one safety layer (9, 40, 50) which is arranged between two successive piezoelectric layers (2) instead of one of the inner electrode layers (3, 4). The safety layer (9, 40, 50) is structured in such a manner that it has an internal interruption (13, 44, 45, 53) which is configured in such a manner that the safety layer (9, 40, 50) does not form an electrical contact between the two outer electrodes (7, 8) if it contact-connects both outer electrodes (7, 8) and is electrically conductive.

Abstract: In a piezoelectric multilayer actuator (1) having micromechanical relief zones (30) and an insulation layer (40) as well as in a method for producing said actuator, as a result of the micromechanical relief zones (30), poling cracks are concentrated in these relief regions (30). This makes it possible to provide the sections I, II, III of the multilayer actuator (1) with an insulation layer (40) which only has an extension behavior similar to the multilayer actuator (1) without poling cracks.

Abstract: A piezoceramic multilayer actuator (10) includes a plurality of green layers, wherein the green layers are to be converted to piezoceramic layers (12) with a piezoceramic material in a subsequent step of heating. A security layer material mixture with a second material (32) and particles (30) embedded in the second material (32) is provided, wherein the particles (30) have a third material different from the first material and different from the second material (32). The security layer material mixture is laminated between two piezoceramic layers (12), thereby forming a green stack. The green stack is heated to a sintering temperature, wherein the green layers are converted to the piezoceramic layers (12), and wherein a chemical reaction of the third material degrades the mechanical connection of the piezoceramic layers (12) by the security layer (20).

Abstract: A piezoactuator of monolithic multilayer design with an overall stack has at least one piezoelectrically active partial stack with piezoceramic layers arranged one above another and electrode layers arranged between these layers, at least one piezoelectrically inactive terminating region arranged above the partial stack, and at least one transition region arranged between the partial stack and the terminating region.

Abstract: A piezoelectric actuator unit which undergoes less change in the amount of displacement and shows high durability in continuous operation under a high voltage and a high pressure over a long period of time is provided. The piezoelectric actuator unit including a multi-layer piezoelectric element having piezoelectric layers and metal layers with the piezoelectric layers and the metal layers being stacked one on another, and a case which houses the multi-layer piezoelectric element, wherein at least one of the plurality of metal layers is stress relieving layer which consists of a plurality of partial metal layers that are scattered throughout the entire region between two piezoelectric layers which adjoin the partial metal layers in the direction of stacking, and voids, and a peel-off section is formed at least in a part of the interface between the stress relieving layer and the piezoelectric layer that adjoins therewith.

Abstract: A piezoceramic multilayer actuator (10) has a plurality of piezoceramic layers (12), a security layer (20) and a plurality of inner electrodes (16, 18). The piezoceramic layers (12) has a piezoceramic first material sintered at a sintering temperature. The security layer (20) has a second material and is disposed between two piezoceramic layers (12). Each of the plurality of inner electrodes (16, 18) has a third material and is deposited between two piezoceramic layers (12). The degree of sintering of the second material is lower than the degree of sintering of the third material.

Abstract: A piezoceramic multilayer actuator (10) has a plurality of piezoceramic layers (12) and a security layer (20) disposed between two piezoceramic layers (12). The piezoceramic layers (12) have a piezoceramic first material sintered at a sintering temperature. The security layer (20) has a second material (32) and particles (30) at least partially embedded in the second material (32). The particles (30) have a third material different from the first material and different from the second material (32). An adhesion between the third material and the first material is weaker than an adhesion between the second material (32) and the first material.

Abstract: A piezoelectric stack (1) has alternately successive piezoelectric layers (2) and inner electrode layers (3, 4) which are alternately electrically connected to two outer electrodes (7, 8) which are arranged on the outer side (5, 6) of the piezoelectric stack (1). The piezoelectric stack (1) also has at least one safety layer (9, 40, 50) which is arranged between two successive piezoelectric layers (2) instead of one of the inner electrode layers (3, 4). The safety layer (9, 40, 50) is structured in such a manner that it has an internal interruption (13, 44, 45, 53) which is configured in such a manner that the safety layer (9, 40, 50) does not form an electrical contact between the two outer electrodes (7, 8) if it contact-connects both outer electrodes (7, 8) and is electrically conductive.

Abstract: A piezoceramic multilayer actuator has a first sub-stack (12, 14, 16) with a plurality of piezoceramic layers (22) and at least one internal electrode (24, 26), the piezoceramic layers (22) and the at least one internal electrode (24, 26) being laminated in an alternating manner, a second sub-stack (12, 14, 16) has a plurality of piezoceramic layers (22) and at least one internal electrode (24, 26), the piezoceramic layers (22) and the at least one internal electrode (24, 26) being laminated in an alternating manner, and a connection layer (40) arranged between the first sub-stack (12, 14, 16) and the second sub-stack (12, 14, 16), wherein the connection layer (40) is set up by a multitude of single connection points or connection lines (44) or other connection regions.