US 9,755,493 B2Granted

Linear motor and stage apparatus

AssigneeShanghai Micro Electronics Equipment (Group) Co., Ltd.

InventorsLiwei Wu, Qingsheng Chen, Lanzhou Yan

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Abstract

A linear motor includes a magnet unit and a coil unit. The magnet unit includes two magnet arrays oppositely parallel and symmetrically located on a magnetic yoke: a first and a second magnet array. The coil unit is disposed in a magnetic gap between the two magnet arrays. In a spatial rectangular coordinate system defined by X, Y and Z axes, the coil unit includes a first and a second coil array arranged in a stacked manner in the Z-axis direction and staggered from each other by a distance of ΔP in the Y-axis direction. ΔP satisfies: when a control system charges the coil unit with a desired current, the coil unit generates a control force along the Y-axis direction, another control force along the Z-axis direction, and a moment about the X-axis direction, which may reduce a magnetic flux leakage and provide higher driving forces, making the linear motor generate required three degrees-of-freedom control force or control torque, and further improve vertical and horizontal magnetic fluxes in the magnet array.

Claims18

Dependent claims

A linear motor comprising a magnet unit and a coil unit, the magnet unit comprising a first magnet array and a second magnet array arranged on a magnetic yoke, symmetrically and in parallel to each other, the coil unit being disposed in a magnetic gap formed between the first and second magnet arrays, wherein in a spatial rectangular coordinate system defined by X, Y and Z axes, the coil unit comprises a first coil array and a second coil array arranged in a stacked manner in the Z-axis direction and the first and second coil arrays are staggered from each other by a distance of ΔP in the Y-axis direction, and ΔP is so set that when the coil unit is provided with a desired electrical current from a control system, the coil unit generates a first control force along the Y-axis direction, a second control force along the Z-axis direction, and a moment about the X-axis direction,

wherein each of the first and second magnet arrays is composed of first-type magnets, second-type magnets and third-type magnets arranged along the Y-axis direction in a similar periodically alternating manner of a Halbach array, each of the third-type magnets being interposed between a corresponding one of the first-type magnets and an adjacent one of the second-type magnets, wherein the first-type magnets and second-type magnets are arranged along the Y-axis direction in an alternating and equidistant manner, wherein each of the third-type magnets is a one-piece unitary prismatic magnet or comprises three prismatic magnets, when each of the third-type magnets is a one-piece unitary prismatic magnet, each pair of adjacent magnets has oblique abutting side faces, and when each of the third-type magnets comprises three prismatic magnets, each pair of adjacent ones of the three prismatic magnets has oblique abutting side faces, and wherein each set of one of the third-type magnets, the adjacent one of the first-type magnets and the adjacent one of the second-type magnets, of one of the first and second magnet arrays, jointly forms a closed magnetic circuit with a corresponding set of the other symmetrical one of the first and second magnet arrays.

A stage apparatus, comprising a stage and two support legs disposed on opposing ends of the stage, wherein the stage is provided with a driving force in a Y-axis direction and a levitation force in a Z-axis direction from motors arranged on tops of the respective support legs, wherein each of the motors comprises a magnet unit and a coil unit, the magnet unit comprising a first magnet array and a second magnet array arranged on a magnetic yoke, symmetrically and in parallel to each other, the coil unit being disposed in a magnetic gap formed between the first and second magnet arrays, wherein in a spatial rectangular coordinate system defined by X, Y and Z axes, the coil unit comprises a first coil array and a second coil array arranged in a stacked manner in the Z-axis direction and the first and second coil arrays are staggered from each other by a distance of ΔP in the Y-axis direction, and ΔP is so set that when the coil unit is provided with a desired electrical current from a control system, the coil unit generates a first control force along the Y-axis direction, a second control force along the Z-axis direction, and a moment about the X-axis direction,

wherein each of the first and second magnet arrays is composed of first-type magnets, second-type magnets and third-type magnets arranged along the Y-axis direction in a similar periodically alternating manner of a Halbach array, each of the third-type magnets being interposed between a corresponding one of the first-type magnets and an adjacent one of the second-type magnets, wherein the first-type magnets and second-type magnets are arranged along the Y-axis direction in an alternating and equidistant manner, wherein each of the third-type magnets is a one-piece unitary prismatic magnet or comprises three prismatic magnets, when each of the third-type magnets is a one-piece unitary prismatic magnet, each pair of adjacent magnets has oblique abutting side faces, and when each of the third-type magnets comprises three prismatic magnets, each pair of adjacent ones of the three prismatic magnets has oblique abutting side faces, and wherein each set of one of the third-type magnets, the adjacent one of the first-type magnets and the adjacent one of the second-type magnets, of one of the first and second magnet arrays, jointly forms a closed magnetic circuit with a corresponding set of the other symmetrical one of the first and second magnet arrays.

Dependencies are inferred from the claim text.