Linear motor magnetic shield apparatus

摘要

A magnetic shield having non-magnetic gaps provides reduced magnetic cross-talk for a linear motor array in a precision positioning system. Redirecting the leakage flux limits the cross-talk and associated deleterious effects. Such preferred magnetic circuit paths for the leakage are affixed to the moving magnet system of the linear motor. Embodiments of the preferred flux leakage paths are realized by providing a ferromagnetic shield separated by a non-magnetic gap between the permanent magnets and the back-irons. In another embodiment, the ferromagnetic shield separation includes diamagnetic materials.

主权项

1. A linear motor, comprising:
a first back iron and a second back iron extending in a first direction; a first plurality of magnetized poles arranged with alternating polarity to each other in the first direction, wherein the first plurality of magnetized poles are coupled to the first back iron; a second plurality of magnetized poles arranged with alternating polarity to each other in the first direction, wherein the second plurality of magnetized poles are coupled to the second back iron and wherein the second plurality of magnetized poles are arranged opposite to the first plurality of magnetized poles; a coil disposed within a gap, wherein the gap separates the first plurality of magnetized poles from the second plurality of magnetized poles; a first shield disposed in a first leakage flux pathway, wherein the first shield is separated from the first plurality of magnetized poles and is separated from the first back iron, the first shield comprises a first part and a second part detached from the first part, and the first back iron is located between the first part and the second part of the first shield; and a second shield disposed in a second leakage flux pathway, wherein the second shield is separated from the second plurality of magnetized poles, is separated from the second back iron, and is detached from the first shield, wherein the second shield comprises a third part and a fourth part detached from the third part, the second back iron is located between the third part and the fourth part of the second shield, and the third and fourth parts of the second shield are detached from the first and second parts of the first shield.