A circumferential seal assembly suitable for forming a thin film between a rotatable runner and a sealing ring is presented. The assembly includes an annular seal housing, a rotatable runner, an annular seal ring, and a plurality of groove structures. Each groove structure includes a groove and an optional feed groove. The groove includes at least two adjoining steps defined by base walls arranged to decrease depthwise. Two adjoining base walls are disposed about a base shoulder. Each base shoulder locally redirects a longitudinal flow to form an outward radial flow in the direction of the annular seal ring. The base walls are bounded by and intersect a pair of side walls. A side wall includes side shoulders which narrows the groove widthwise and locally redirects the longitudinal flow to form a lateral flow in the direction of the other side wall. Outward and lateral flows separately or in combination enhance stiffness of a thin-film layer between the annular seal ring and the rotatable runner.

A thrust gas bearing includes a collar portion fixed to a shaft portion, a first base part facing one axial end surface of the collar portion, a first gas film forming part formed between the collar portion and first base part, a second base part facing an other axial end surface of the collar portion, a second gas film forming part formed between the collar portion and second base part, and a cooling flow path to carry a fluid flow. The cooling flow path includes a first flow path formed on one axial end side of the first base part and extending from an axial center toward an outer periphery, and a second flow path formed on an other axial end side of the second base part and extending from an outer periphery toward an axial center. The second flow path is located downstream of the first flow path.

An air bearing for calibrating a force measurement device comprises an inner wall, an outer wall, an upper wall, a lower wall, an internal chamber, an object retention opening, and a plurality of air outlets. The inner wall and outer wall each have a cylindrical shape with the outer wall being concentric with the inner wall. The upper wall and lower wall each have an annular shape and are attached to the inner wall and the outer wall. The internal chamber is formed by inner surfaces of the four walls, and is configured to retain compressed air. The object retention opening is formed by an outer surface of the inner wall and is configured to receive and retain an object. The air outlets are positioned along the inner wall and are configured to allow compressed air to flow from the internal chamber to the object retention opening.

Provided is a floating-sleeve hybrid fluid bearing. The floating-sleeve hybrid fluid bearing may comprise: a bearing housing which is mounted by ring-coupling to the outer circumferential surface of a rotary shaft; and a floating sleeve which is mounted between the rotary shaft and the bearing housing so that there is a gap between the floating sleeve and the rotary shaft, and between the floating sleeve and the bearing housing, wherein the rotation of the floating sleeve is constrained by the bearing housing during the rotation of the rotary shaft, and one side of the floating sleeve in the circumferential direction is open in the radial direction.

A cantilever linear motion reference device employing two-layer air suspension. By means of a two-layer force sealed air suspension structure, the invention realizes two-dimensional air suspension support and motion guiding and improves the rotational stiffness per unit for an air suspension working surface. By combining accurate driving and feedback control, the invention achieves high speed, high acceleration, high frequency motion, and enables construction of a small-volume, long cantilever, high torque load two-dimensional motion reference device.

A gas dynamic bearing includes a shaft extending along a central axis extending vertically, and a sleeve with a hole opening at least at one end of the sleeve in an axial direction, at least a portion of the shaft housed inside the hole. The sleeve includes dynamic pressure grooves in an inner peripheral surface of the hole. The shaft includes a core portion, and a protective portion that is disposed on an outer peripheral surface of the core portion and that includes at least a portion facing the inner peripheral surface of the hole in a radial direction. The protective portion includes a first protective portion and a second protective portion. The first protective portion is at least above or below the second protective portion in the axial direction, and includes at least a portion with a thickness in the radial direction more than a thickness of the second protective portion in the radial direction.

A support table for a lithographic apparatus, a method of loading a substrate, a lithographic apparatus and a method for manufacturing a device using a lithographic apparatus. In one arrangement, a support table is configured to support a substrate. The support table has a base surface. The base surface faces a surface of the substrate when the substrate is supported by the support table. One or more gas cushion members are provided above the base surface. Each of the gas cushion members includes a recess. The recess is shaped and configured such that a lowering of the substrate into a position on the support table at which the substrate is supported by the support table causes a localised build-up of pressure within the recess. The localized build-up of pressure provides a localised gas cushioning effect during the lowering of the substrate.

A cantilever linear motion reference device employing two-layer air suspension. By means of a two-layer force sealed air suspension structure, the invention realizes two-dimensional air suspension support and motion guiding and improves the rotational stiffness per unit for an air suspension working surface. By combining accurate driving and feedback control, the invention achieves high speed, high acceleration, high frequency motion, and enables construction of a small-volume, long cantilever, high torque load two-dimensional motion reference device.

An active aerostatic bearing comprises a first plate and a force actuator. The first plate has a central recess area including an orifice forming an inlet restrictor for pressurized air from a central nozzle. The pressurized air forms an air gap between a guiding surface and the first plate. The force actuator is configured to act to deform the first plate so as to change a shape of the air gap, wherein the actuator is configured to cause a conical deformation of the first plate.

A rotary machine for an aeronautical device includes a thrust generator. The rotary machine additionally includes a rotary component rotatable with the thrust generator. Moreover, the rotary machine of the present disclosure includes a plurality of gas bearings, with the plurality of gas bearings substantially completely supporting the rotary component of the rotary machine.