Electrification of a landing gear – actuators with toothed coupling

Abstract

This study presents the design of an electric motorisation for a landing gear. The concept of More Electric Aircraft is currently with one of the major concerns of all aircraft manufacturers and equipment suppliers throughout the world. The objective consists of eliminating, to the greatest extent possible, the use of any actuator containing fluid pressure and increasing the use of electric actuators. This applies to all airplane orders and accessories. The choice of this motorisation was to design synchronous machines with toothed coupling. When actuators of very high mass performance are required, the use of this type of actuator is an interesting solution, compared with conventional actuators with polar coupling. The principles used in our design method are based on two-dimensional finite-element simulations. The study and the calculation can be performed in two dimensions from a simple element called an elementary pattern, representing the interaction of magnets with stator teeth. Following a summary presentation of this type of actuator and its dimensioning, two prototypes are presented. To replace the hydraulic cylinders in the landing gear of an A320 aircraft, a vernier machine, and a multi-air gap linear motor has been dimensioned, manufactured and tested.