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

A rotation mechanism includes: a housing; a shaft inserted through a hole provided at the housing; bearings installed at the housing and rotatably supporting the shaft; a rotary member provided at one end portion of the shaft, adapted to be rotated together with the shaft, and having a portion that projects to a radially outer side of the hole and faces the housing with a gap having a predetermined size; and a gas passage adapted to connect the gap to outside of the housing and allow gas contained in a portion of the gap to pass to the outside of the housing.

A rotation mechanism includes: a housing; a shaft inserted through a hole provided at the housing; bearings installed at the housing and rotatably supporting the shaft; a rotary member provided at one end portion of the shaft, adapted to be rotated together with the shaft, and having a portion that projects to a radially outer side of the hole and faces the housing with a gap having a predetermined size; and a gas passage adapted to connect the gap to outside of the housing and allow gas contained in a portion of the gap to pass to the outside of the housing.

A hydrostatic bearing is provided which may include foot part supporting a load- carrying unit, a head part, and body part forming a lower chamber and an upper chamber. A lower member is supported by the load-carrying unit and arranged inside the lower chamber. An upper member is controllable by a pressurizing fluid and arranged inside the upper chamber. The lower member is controllably moveable along a central axis of the hydrostatic bearing between a retracted state, where the lower member is distanced from the upper member, and an extended state, where the lower member is also in contact with the upper member. The hydrostatic bearing acts both as a conventional slave bearing and a conventional master bearing.

Applicant respectfully submits that no new matter is entered into this application by the new abstract.

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.

An axial load management system for a turbomachine including a rotating drivetrain, a thrust bearing assembly, a sensor, and a valve supply line. The rotating drivetrain includes a compressor section and an expander section fluidly coupled together by a closed flowpath. The thrust bearing assembly includes a thrust runner, a thrust bearing housing, and a gas thrust bearing extending between the thrust runner and the thrust bearing housing. Further, the gas thrust bearing supports the rotating drivetrain. The sensor is attached to at least one of the thrust bearing housing or the gas thrust bearing. The valve supply line is fluidly coupled to the closed flowpath. A valve positioned within the valve supply line selectively allows a working fluid to flow between the closed flowpath and a thrust chamber defined by a rotating surface and a fixed surface to modify an axial load on the rotating drivetrain.

An axial load management system for a turbomachine including a rotating drivetrain, a thrust bearing assembly, a sensor, and a valve supply line. The rotating drivetrain includes a compressor section and an expander section fluidly coupled together by a closed flowpath. The thrust bearing assembly includes a thrust runner, a thrust bearing housing, and a gas thrust bearing extending between the thrust runner and the thrust bearing housing. Further, the gas thrust bearing supports the rotating drivetrain. The sensor is attached to at least one of the thrust bearing housing or the gas thrust bearing. The valve supply line is fluidly coupled to the closed flowpath. A valve positioned within the valve supply line selectively allows a working fluid to flow between the closed flowpath and a thrust chamber defined by a rotating surface and a fixed surface to modify an axial load on the rotating drivetrain.