Apparatus for controlled movement of an element

摘要

A method and apparatus for supporting a movable member ( 10 ) with respect to a fixed member ( 40 ) is provided. The movable member ( 10 ) includes a magnetically permeable portion ( 81 ) contained therein and magnetic element ( 50 ) fixedly attached thereto and movable therewith. The movable member ( 10 ) is supported for rotation with respect to the fixed member ( 40 ) by an outer bearing surface ( 11 ) of the movable member and an inner bearing surface ( 20 ) of the fixed member ( 40 ). The fixed member ( 40 ) provides access to the movable member ( 10 ) from two sides thereof. A magnetically permeable stator element ( 70 ) is fixedly attached to the fixed member ( 40 ) and positioned within a magnetic flux field of the magnetic element ( 50 ) such that an air gap ( 73 ) is formed between the magnetic element ( 50 ) and the stator element ( 70 ). Accordingly a magnetic traction force acts across the air gap ( 73 ) for urging the moveable member ( 10 ) toward the fixed member ( 40 ) thereby clamping the movable element in a fixed orientation with respect to the movable element. The stator element ( 70 ) includes stator current coils ( 60 ) wound onto portions of the stator element for inducing electromagnetic forces within the stator element in response to a current passing through the coils. The electromagnetic force acts on the magnetic element ( 50 ) to move the movable member ( 10 ) in a controllable manner.