Multilayer piezo actuator for Diesel oil injection system with feature restricting formation of cracks and process for producing thereof

摘要

A piezo-multilayer actuator having a plurality of piezoceramic layers (2) arranged in a stack and a plurality of inner electrodes (22, 32) interleaved in the piezoceramic layers (2), the plurality of inner electrodes extending from first and second sides of the stack in alternating fashion. First and second outer electrodes (42, 52) are connected to the plurality of inner electrodes extending respectively from the first and second sides of the stack. The inner electrodes include thickened portions (26) at the first and second connection areas, the thickened portions being thicker than other portions of the plurality of inner electrodes so as to reinforce the inner electrodes. Cracks (72) which may form on the inner electrodes due to tensile stresses tend to migrate around the thicker portions of the inner electrodes at the first and second connection areas. Propagation of the cracks to the outer electrodes with the attendant possibility of current interruption in the outer electrodes, is thereby reduced or halted.