Abstract:
The present invention relates an actuator arrangement for use in a fuel injector, comprising: a piezoelectric actuator having a body section, said body section having a first end piece and a second end piece; a sleeve which enshrouds at least part of the body section of the actuator; and at least one constrictive member, disposed externally with respect to the sleeve wherein the constrictive member applies a constrictive force to the sleeve to maintain a seal between the sleeve and the underlying body section of the actuator. The underlying body section comprises an alternation of smooth sections and rough sections; said rough sections comprising superficial markings.
Abstract:
The invention concerns an encapsulated actuator as well as a method of encapsulating an actuator/stack in an encapsulation member, which comprising at least an innermost heat shrinkable, polymeric sleeve member and an overlaying outermost, heat shrinkable, polymeric sleeve member. The sleeve members have each a different shrinkage temperature, wherein the shrinkage temperature of the outermost sleeve member is higher than the shrinkage temperature of the innermost sleeve member. The method comprising essentially the following steps: a. Arranging the stack inside the innermost sleeve member, b. Arranging the outermost sleeve member so as to overlay the innermost sleeve member(s), c. Placing the stack under vacuum so as to degas it, d. Heating the stack above the shrinkage temperature of the outermost sleeve member so as to shrink the outermost sleeve member, e. Placing the stack under atmospheric pressure f. Cooling the stack.