ELECTRICALLY CONTROLLED BRAKE

摘要

An electrically controlled brake includes as conventional a rotatable first mechanical system and a second mechanical system that is stationary or fixed. The two systems have friction surfaces/parts (110) that can be made to come in engagement with each other, providing a braking effect, and be withdrawn from each other releasing the braking effect. In the second system, windings can be wound around two braking shoes (102, 103) made from soft magnetic material so that an electric current flowing in the windings affects magnetic fluxes through the soft magnetic parts to move at least one thereof. The movement is in a direction that affects the effective width of an air gap (107) in the closed main magnetic path. The electric current gives attraction forces over the air gap which tend to move the braking shoes to reduce the length of the air gap. A spring (107) that e.g. can be a flat spring is rigidly mounted to inner ends of the braking shoes, creating forces on the braking shoes acting in a direction substantially opposite that of the attraction forces. The spring and the braking shoes form a unified structure that via a portion of the spring is rigidly attached to a stationary component (111) of the brake, such as through a bar (105). Since the movements of the braking shoes is not performed about some shaft or articulation, there is no mechanical play in the brake.