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 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 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 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 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 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 multi-layer piezoelectric element which undergo less change in the amount of displacement and shows high durability during continuous operation under a high voltage and pressure over a long period are provided. The multi-layer piezoelectric element comprises 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, wherein at least one of the metal layers is stress relieving layer having partial metal layers scattered between the two piezoelectric layers and voids, wherein 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 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: In a method of manufacturing a piezoceramic multilayer actuator (10), a plurality of green layers is provided, 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).