Method for producing a monolithic piezo actuator with stack elements, monolithic piezo actuator with stack elements, and use of the piezo actuator

Abstract

A piezo actuator has a stack element and at least one further stack element, wherein each of the stack elements has stacked piezoceramic layers and electrode layers arranged between the piezoceramic layers, each of the electrode layers extends to at least one of at least two lateral surface sections of the stack element which have external metallizations on them, and are connected to the electrode layers such that adjacently stacked electrode layers can have different electrical potentials applied to them indirectly via the external metallizations, the stack elements are arranged above one another to form a monolithic total stack, and connected to one another by at least one connecting layer. The following steps are provided: a) provision of the total stack and b) production of a load-relieving crack in the connecting layer. An electrical connector in the form of a wire can be fitted on the relevant external metallization regions.

1 . A method for producing a monolithic multilayer piezo actuator, comprising:
 a stack element and   at least one further stack element, wherein   each of the stack elements comprises piezoceramic layers arranged above one another and electrode layers arranged between the piezoceramic layers,   each of the electrode layers of the respective stack element extends to at least one of at least two side surface sections of the stack element,   external metallizations are arranged on the side surface sections of the respective stack element and are connected to the electrode layers of the stack element, such that different electrical potentials can be applied directly to the electrode layers of the stack elements arranged adjacently above one another via the external metallizations,   the stack elements are arranged above one another into a monolithic total stack and   the stack elements are connected to each other with the aid of at least one connecting layer arranged between the stack elements,   the method comprises the following steps:   a) Preparation of the total stack and   b) Creation of a load-relieving crack of the connecting layer.   
     
     
         2 . The method according to  claim 1 , wherein the following further method steps being executed to create the load-relieving crack:
 c) Polarization of the stack element and   d) Polarization of the further stack element.   
     
     
         3 . The method according to  claim 2 , wherein the electrode layers of the further stack element being short circuited during the polarization of the stack element. 
     
     
         4 . The method according to  claim 1 , wherein the following further method steps being executed to create the load-relieving crack:
 e) Polarization of the total stack and   f) Depolarization of one of the stack elements.   
     
     
         5 . The method according to  claim 2 , wherein a part polarization being carried out for polarization of the stack element and/or for polarization of the further stack element. 
     
     
         6 . The method according to  claim 2 , wherein a compressive stress being applied to the total stack during the polarization of the stack element and/or during the polarization of the further stack element and/or during the polarization of the total stack and/or during of the depolarization of one of the stack elements. 
     
     
         7 - 10 . (canceled) 
     
     
         11 . A method for producing a monolithic multilayer piezo actuator, comprising:
 providing a stack element and at least one further stack element,   arranging piezoceramic layers of each of the stack elements above one another and electrode layers between the piezoceramic layers, wherein each of the electrode layers of the respective stack element extends to at least one of at least two side surface sections of the stack element,   arranging external metallizations on the side surface sections of the respective stack element and connecting the external metallizations to the electrode layers of the stack element, such that different electrical potentials can be applied directly to the electrode layers of the stack elements arranged adjacently above one another via the external metallizations,   arranging the stack elements above one another into a monolithic total stack and   connecting the stack elements to each other with the aid of at least one connecting layer arranged between the stack elements, and   creating a load-relieving crack of the connecting layer.   
     
     
         12 . The method according to  claim 11 , wherein the following further method steps being executed to create the load-relieving crack:
 polarizing the stack element, and   polarizing the further stack element.   
     
     
         13 . The method according to  claim 12 , wherein the electrode layers of the further stack element being short circuited during the polarization of the stack element. 
     
     
         14 . The method according to  claim 11 , wherein the following further method steps being executed to create the load-relieving crack:
 polarizing the total stack, and   depolarizing one of the stack elements.   
     
     
         15 . The method according to  claim 12 , wherein a part polarization being carried out for polarization of the stack element and/or for polarization of the further stack element. 
     
     
         16 . The method according to  claim 12 , wherein a compressive stress being applied to the total stack during the polarization of the stack element and/or during the polarization of the further stack element and/or during the polarization of the total stack and/or during of the depolarization of one of the stack elements.