PIEZOELECTRIC ACTUATOR UNIT WITH IMPROVED HEAT DISSIPATION AND FUEL INJECTOR

摘要

The invention relates to a piezoelectric actuator unit (13) and to a fuel injector (11) that is configured with a piezoelectric actuator unit (13). The problem of generic structures of this kind is that the heat dissipated in the actuator unit (13), especially during multiple injections, is not dissipated into the environment in an optimum manner, thereby leading to an overheating which may impair the function of the actuator unit (13) and of the fuel injector (11). The aim of the invention is therefore to improve heat dissipation. For this purpose, a cavity (16) is defined between an actuator module (8) and a plastic sleeve (2) configured as a casting mold and is filled with a casting compound (6). Said casting compound (6) has a plurality of pores and/or interstices (9) and is an open-pore compound to a degree well over the percolation limit. In this manner, not only thermal conductivity is improved but also the actuator module (8) is electrically passivated, especially if the pores or interstices (9) are filled with a liquid.