A structure and method of operation of a journal bearing is disclosed that minimizes contact of the shaft with the sleeve during start up and slow down of rotation of the shaft relative to the sleeve, or vice versa. The bearing assembly includes a gravitational load reduction mechanism with magnets disposed on the sleeve and on the shaft in alignment with one another. The magnet(s) on the shaft interacts with the magnet(s) disposed on the sleeve to provide a force against the pressure of the shaft towards the sleeve generated by gravity on the rotating component. The magnets enable centering of the rotating component within the stationary component during low rotation and non-rotation. This prevents rubbing of the rotating journal bearing component surfaces, e.g., sleeve, against the stationary journal bearing component, e.g., shaft, during assembly, ramp-up, and coast-down when the journal bearing fluid provides minimal or no bearing centering capability.

A structure and method of operation of a journal bearing is disclosed that minimizes contact of the shaft with the sleeve during start up and slow down of rotation of the shaft relative to the sleeve, or vice versa. The bearing assembly includes a gravitational load reduction mechanism with magnets disposed on the sleeve and on the shaft in alignment with one another. The magnet(s) on the shaft interacts with the magnet(s) disposed on the sleeve to provide a force against the pressure of the shaft towards the sleeve generated by gravity on the rotating component. The magnets enable centering of the rotating component within the stationary component during low rotation and non-rotation. This prevents rubbing of the rotating journal bearing component surfaces, e.g., sleeve, against the stationary journal bearing component, e.g., shaft, during assembly, ramp-up, and coast-down when the journal bearing fluid provides minimal or no bearing centering capability.

The invention relates to a bearing device arranged to support in a vertical direction a first part of an apparatus with respect to a second part of the apparatus, comprising a magnetic gravity compensator. The magnetic gravity compensator comprises:

a first permanent magnet assembly mounted to one of the first part and the second part and comprising at least a first column of permanent magnets, the first column extending in the vertical direction, wherein the permanent magnets have a polarization direction in a first horizontal direction or in a second horizontal direction opposite to the first horizontal direction, wherein vertically adjacent permanent magnets have opposite polarization directions,

a second permanent magnet assembly mounted to the other of the first part and the second part and comprising at least one other column of permanent magnets, the at least one other column extending in the vertical direction, wherein vertically adjacent permanent magnets of the at least one other column have opposite polarization directions in the first horizontal direction or the second horizontal direction,

wherein the first permanent magnet assembly at least partially encloses the second permanent magnet assembly.

Provided are a tape guide roller and tape drive having a guide roller having magnets and bushings to stabilize a roller barrel for a tape medium. The tape guide roller has a roller barrel extending around a vertical axis. The tape medium passes across the roller barrel to guide the tape medium on a tape path. A plurality of magnets positioned with respect to the vertical axis provide an axial force to stabilize the tape guide roller axially.

In a substrate stage, when a Y coarse movement stage moves in the Y-axis direction, an X coarse movement stage, a weight cancellation device, and an X guide move integrally in the Y-axis direction with the Y coarse movement stage, and when the X coarse movement stage moves in the X-axis direction on the Y coarse movement stage, the weight cancellation device move on the X guide in the X-axis direction integrally with the X coarse movement stage. Because the X guide is provided extending in the X-axis direction while covering the movement range of the weight cancellation device in the X-axis direction, the weight cancellation device is constantly supported by the X guide, regardless of its position. Accordingly, a substrate can be guided along the XY plane with good accuracy.

In a substrate stage, when a Y coarse movement stage moves in the Y-axis direction, an X coarse movement stage, a weight cancellation device, and an X guide move integrally in the Y-axis direction with the Y coarse movement stage, and when the X coarse movement stage moves in the X-axis direction on the Y coarse movement stage, the weight cancellation device move on the X guide in the X-axis direction integrally with the X coarse movement stage. Because the X guide is provided extending in the X-axis direction while covering the movement range of the weight cancellation device in the X-axis direction, the weight cancellation device is constantly supported by the X guide, regardless of its position. Accordingly, a substrate can be guided along the XY plane with good accuracy.

In a substrate stage, when a Y coarse movement stage moves in the Y-axis direction, an X coarse movement stage, a weight cancellation device, and an X guide move integrally in the Y-axis direction with the Y coarse movement stage, and when the X coarse movement stage moves in the X-axis direction on the Y coarse movement stage, the weight cancellation device move on the X guide in the X-axis direction integrally with the X coarse movement stage. Because the X guide is provided extending in the X-axis direction while covering the movement range of the weight cancellation device in the X-axis direction, the weight cancellation device is constantly supported by the X guide, regardless of its position. Accordingly, a substrate can be guided along the XY plane with good accuracy.

In a substrate stage, when a Y coarse movement stage moves in the Y-axis direction, an X coarse movement stage, a weight cancellation device, and an X guide move integrally in the Y-axis direction with the Y coarse movement stage, and when the X coarse movement stage moves in the X-axis direction on the Y coarse movement stage, the weight cancellation device move on the X guide in the X-axis direction integrally with the X coarse movement stage. Because the X guide is provided extending in the X-axis direction while covering the movement range of the weight cancellation device in the X-axis direction, the weight cancellation device is constantly supported by the X guide, regardless of its position. Accordingly, a substrate can be guided along the XY plane with good accuracy.

Provided are a tape guide roller and tape drive having a guide roller having magnets and bushings to stabilize a roller barrel for a tape medium. The tape guide roller has a roller barrel extending around a vertical axis. The tape medium passes across the roller barrel to guide the tape medium on a tape path. A plurality of magnets positioned with respect to the vertical axis provide an axial force to stabilize the tape guide roller axially.

Magnetically coupled mixer having an impeller magnetically coupled to a drive shaft and thrust bearings that support the impeller. The drive shaft can be moved along its axis, and an upwardly directed axial force is applied to the drive shaft to partially offset downward forces exerted by the impeller and thereby reduce friction between the thrust bearing surfaces while maintaining contact between them. In one disclosed embodiment, the force is applied to the drive shaft by a pair of magnets arranged so that the magnetic fields interact to produce the force, and the magnitude of the force is controlled by adjusting the distance between the magnets. The forces exerted by the impeller can be monitored and utilized in controlling the magnitude of the force applied to the shaft.