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.

A device for producing a releasable clearance-free position of a rolling bearing, having a rolling bearing which has an outer ring, an inner ring mounted on a shaft and a plurality of rolling elements arranged between the inner ring and the outer ring, and having a tensioning device mounted on the circumference of the rolling bearing outer ring for generating a radial preload which is uniform over the outer circumference of the rolling bearing outer ring between the tensioning device and the rolling bearing outer ring, wherein the tensioning device has an axially adjustable tensioning element which can be brought into a first alignment in which the rolling bearing has play, and which can be brought into a second alignment in which the rolling bearing is free of play. A corresponding method is also described.

A device for producing a releasable clearance-free position of a rolling bearing, having a rolling bearing which has an outer ring, an inner ring mounted on a shaft and a plurality of rolling elements arranged between the inner ring and the outer ring, and having a tensioning device mounted on the circumference of the rolling bearing outer ring for generating a radial preload which is uniform over the outer circumference of the rolling bearing outer ring between the tensioning device and the rolling bearing outer ring, wherein the tensioning device has an axially adjustable tensioning element which can be brought into a first alignment in which the rolling bearing has play, and which can be brought into a second alignment in which the rolling bearing is free of play. A corresponding method is also described.

A gas bearing assembly includes a snap joint for attaching an externally pressurized porous gas bearing to a bearing cartridge. The gas bearing assembly has an adjustment screw which supplies a gas to an end of the adjustment screw via a through bore. The externally pressurized porous gas bearing has a housing portion with a washer and a snap ring. The gas bearing assembly additionally includes an air transfer tube positioned in the end of the adjustment screw and the housing portion. The washer and the snap ring retain the housing portion on the end of the adjustment screw to removably retain the bearing on the bearing cartridge.

A gas bearing assembly includes a snap joint for attaching an externally pressurized porous gas bearing to a bearing cartridge. The gas bearing assembly has an adjustment screw which supplies a gas to an end of the adjustment screw via a through bore. The externally pressurized porous gas bearing has a housing portion with a washer and a snap ring. The gas bearing assembly additionally includes an air transfer tube positioned in the end of the adjustment screw and the housing portion. The washer and the snap ring retain the housing portion on the end of the adjustment screw to removably retain the bearing on the bearing cartridge.

An apparatus (10) for preloading a bearing assembly (14) on a shaft (12) includes a first annular threaded member (56) positioned about the shaft (12) and a second annular threaded member (68) positioned about the shaft (12). The first and second threaded members (56,68) have intermeshing threads such that rotation of the second threaded member (68) causes axial translation of the first threaded member (56) to apply a first axial force to the bearing assembly (14) to preload the bearing assembly (14). An actuator is operable to rotate the second threaded member (68) relative to the first threaded member (56) to apply the first axial force to the bearing assembly (14).

An oil supply assembly for a bearing damper of a gas turbine engine includes an oil supply tube configured to supply oil in a first direction. The assembly also includes a bearing support having a bearing damper path connecting the bearing damper to the oil supply tube and a bearing compartment path connecting a bearing compartment to the oil supply tube. The assembly also includes a check valve disposed within the bearing damper path and configured to allow fluid communication in the first direction from the oil supply tube to the bearing damper and block fluid communication in a second direction opposite the first direction.

An oil supply assembly for a bearing damper of a gas turbine engine includes an oil supply tube configured to supply oil in a first direction. The assembly also includes a bearing support having a bearing damper path connecting the bearing damper to the oil supply tube and a bearing compartment path connecting a bearing compartment to the oil supply tube. The assembly also includes a check valve disposed within the bearing damper path and configured to allow fluid communication in the first direction from the oil supply tube to the bearing damper and block fluid communication in a second direction opposite the first direction.

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.