Design of Integrated Magnetic Springs for Linear Oscillatory Actuators

Spring assisted oscillating actuators allow to reduce the energy consumption. The concept relies on springs that take and release energy into the system when required. Conventional mechanic springs impose some limitations on the system regarding mainly compactness, friction, material fatigue and failure. Magnetic springs show the potential to overcome these issues especially for long stroke high frequent operation. This paper investigates the integration of a magnetic spring into a linear oscillatory motor, without any changes to the permanent magnet arrangement on the mover. The focus lies on a compact design with maximum energy storage capacity. The proposed design guidelines are used as starting point for a finiteelement based optimization. Moreover the investigation covers the expected losses and demonstrates that a correct choice of materials is crucial for an efficient operation. The results of the simulated spring characteristic as well as the losses are validated with measurements on a prototype of the linear oscillatory motor featuring the proposed integrated magnetic spring.