High force density solenoid actuator for aerospace application

Solenoid is an electromagnetically operated actuator. A typical application of solenoid is to operate valves near aircraft engine, under harsh environmental conditions and high endurance requirements. Under these circumstances usage of higher hardness materials for spindle becomes unavoidable. Unfortunately these materials exhibit magnetic susceptibility. This causes higher flux leakage and reduces the efficacy of the solenoid. Solenoid having very high force to weight ratio over a range of stroke with limited envelope is much appreciated for aerospace and space applications. A novel method of introducing flux router (a nonmagnetic component) at an appropriate location in the solenoid geometry in order to divert the unused magneto motive force (MMF) into working air gap is discussed in this paper. Numerical simulations based on finite element methods is used for performance comparison of conventional and proposed solenoid keeping same applied MMF and simulation parameters for various flux router geometries. This analysis considers worst case solenoid geometry and it also includes method of modeling the practical non-idealities that exists due to manufacturing and assembly process. This analysis also provides input for refinement of solenoid part dimensions and tolerance stack up.