Study on a PZT Actuator Based on Pre-stressed Mechanism

In this paper, a redesign of the prestress mechanism of the stack-type piezoelectric ceramic actuator is provided. Belleville (disc) springs which have a specific height-to-thickness ratio are constructed to generate a constant pre-stress force to the PZT and operated in a special condition. The zero-spring-rate preload mechanism is not only used to handle the tensile stress but also used in both the constant force actuation mode and elastic suspension mode. The feasibility of the concept of the output force and vibration isolation is determined by the experimental results. The comparison of the output force and the dynamic response of the pretress mechanism between the different settings of the actuator designed in this study and the commercial products reveal that the constant output force can be maintained and the new prestress mechanism exhibits an extremely low natural frequency which approach to zero as height-to-thickness ratio of the Belleville springs equal to root 2.