Development of Cylindrical Linear Actuator for Vertical Transfer: Fundamental Consideration of Effect of Shape on Thrust Characteristics

Abstract

  In conventional elevators, vibration and twisting of the cable become a serious problem when the cable is long. Therefore, an elevator that omits the counterweight and is moved by an actuator on a single cable with both ends fixed has been considered. However, contact decreases the efficiency and damages the cable owing to the inclusion of foreign matter. Therefore, a vertical transportation system is proposed that moves above a long, uniform conductor cable without contact by using a cylindrical linear induction motor (LIM) as the actuator. A cylindrical LIM above the reaction plate, which is a cylindrical shell-shaped conductor, has the advantage that the magnetic force acts on the reaction plate uniformly. This suppresses the vibration in the gap direction. However, a conventional LIM drives the mover in the horizontal direction. Therefore, a model was constructed for analyzing the cylindrical LIM for vertical transfer, and electromagnetic field analyses were performed using the finite-element method. The thickness of the reaction plate was varied, and the effect on the generated thrust was investigated. The optimal thickness of the cable was determined from the results by obtaining the range of the magnetic flux density acting on the cable.