Design of a large stroke flexure-based suspension for an iron core torque motor

Iron core torque motors provide a high power density, but require high off-axis stiffness, which is normally too demanding for flexure mechanisms especially when considering large range of motion applications. In this paper, a flexure-based suspension for a high torque iron core direct drive torque motor with a large range of motion of 60 degrees is presented. This flexure-based suspension provides the required high radial stiffness (>1000N/mm) combined with a high radial load capacity (500N) over the full range of motion. Furthermore, the suspension maintains a constant position of the pivot axis within 0.1mm, which is required to limit pull-in forces and to stay within alignment tolerances of the actuator. A prototype has been designed and constructed and experimental validations confirm the high radial stiffness and load capacity of the rotor suspension.