Design of a contactless rotary energy transmission for an industrial application

Till now, the common practice of transferring energy from a stationary to a rotating plane is realized via slip rings. These systems exhibit a small mechanical size but limit the achievable rotational speed. Due to abrasion, the lifetime of slip rings is limited. Contactless rotary energy transmissions can overcome these problems. They are not affected by fouling and are theoretically maintenance-free. This paper deals with the development of a contactless energy transmission for a drilling tool. The developed energy transmission transfers up to 200 W. The transferred energy is used to drive a piezoelectric actuator, which in turn controls the position of the cutting edge of the drilling tool. First, the mechanical constraints of this application are given and the consequences for the energy transmission are derived. Afterwards, the topology most suitable for this application is selected. Subsequently, the different methods to solve the difficulties, which arise from the mechanical constraints, with their advantages and disadvantages are compared and their influence on the design of the components is shown. At the same time, it is determined which degree of mechanical dislocation is allowed before the system will trip.