A method for machining ribs or grooves on a workpiece such as a shaft or an air or gas axial bearing intended to be rotated about a longitudinal axis of a centrifugal compressor. All of the ribs or grooves are obtained at once by the machining tool on a workpiece portion driven such that it rotates, by moving the workpiece or the tool holder in a longitudinal machining direction, the machining tool moving back and forth with a machining position in contact with the workpiece and a position wherein it is not in contact with the workpiece from the start to the end of the workpiece portion. The back-and-forth movements of the machining tool are synchronised with the sinusoidal program set up in the machining unit, as well as with the desired, programmed arrangement of the ribs or grooves to be produced on the workpiece portion.

The invention relates to a compressor (20) for generating a compressed air flow for a fuel cell (10), having a compressor element (21), in particular a compressor wheel, wherein the compressor element (21) is coupled in a to a drive shaft (23) for co-rotation, the drive shaft (23) being driven by a motor (22), in particular an electric motor, wherein at least one hydrodynamic or hydrostatic bearing (24, 25) is used to mount the shaft (23) in a rotatable manner, wherein the plain bearing (24, 25) is connected to a lubricant supply means (30), which is used to supply a lubricant for hydrodynamic or hydrostatic pressure generation to the plain bearing (24, 25), wherein the lubricant is water or a fluid mixture, predominantly comprising water, wherein the plain bearing (24, 25) has a lubricant inlet and a lubricant outlet, wherein the lubricant can be routed to the plain bearing (24, 25) via the lubricant inlet and the lubricant can be discharged from the plain bearing (24, 25) via the lubricant outlet, and wherein a discharge area of the circulation system (30) is disposed in the area of the lubricant outlet. An operationally safe design can be implemented for such a compressor if provision is made for the cross-section area of the outlet of the liquid outlet of the plain bearing (24, 25) to be completely covered by the lubricant held in the discharge area.

The invention relates to a compressor (20) for generating a compressed air flow for a fuel cell (10), having a compressor element (21), in particular a compressor wheel, wherein the compressor element (21) is coupled in a to a drive shaft (23) for co-rotation, the drive shaft (23) being driven by a motor (22), in particular an electric motor, wherein at least one hydrodynamic or hydrostatic bearing (24, 25) is used to mount the shaft (23) in a rotatable manner, wherein the plain bearing (24, 25) is connected to a lubricant supply means (30), which is used to supply a lubricant for hydrodynamic or hydrostatic pressure generation to the plain bearing (24, 25), wherein the lubricant is water or a fluid mixture, predominantly comprising water, wherein the plain bearing (24, 25) has a lubricant inlet and a lubricant outlet, wherein the lubricant can be routed to the plain bearing (24, 25) via the lubricant inlet and the lubricant can be discharged from the plain bearing (24, 25) via the lubricant outlet, and wherein a discharge area of the circulation system (30) is disposed in the area of the lubricant outlet. An operationally safe design can be implemented for such a compressor if provision is made for the cross-section area of the outlet of the liquid outlet of the plain bearing (24, 25) to be completely covered by the lubricant held in the discharge area.

A centrifugal compressor assembly and method of operation provides a motor that drives a first stage compressor. The motor comprises a rotor. The motor uses radial aerostatic bearings to stabilize rotation and axial displacement of the rotor. The motor also uses a thrust aerostatic bearing to balance an axial force of the rotor. The radial aerostatic bearings and the thrust aerostatic bearing use a low-viscous vapor-liquid two-phase fluid as a lubricating medium. The radial aerostatic bearings supports the rotor. The thrust aerostatic bearing uses porous aerostatic bearings that use a low-viscous vapor-liquid two-phase fluid, so as to reduce radial and axial oscillation of the rotor. This enables clearance between a blade tip of an impeller and a volute. This causes a seal clearance to be reduced by a half; thereby increasing efficiency of the centrifugal compressor by at least 10 percent.

A fuel cell including a two-stage, fluid compressor including a case having a fluid inlet and a compressed fluid outlet and containing a shaft rotatably mounted about a longitudinal axis, first and second compression wheels mounted back-to-back on the shaft and forming respectively first and second compression stages, and a motor positioned between the first and second compression wheels and arranged to rotate the shaft. The case includes a through inner housing extending coaxially to the longitudinal axis and inside which is arranged at least the motor, the inner housing having an internal wall arranged to form, with the motor, channels between at least the inner wall and the motor, the channels extending between the first and second compression stages, allowing the motor to be cooled. Further, the case includes at its surface at least one cavity forming at least one integrated housing arranged to receive at least one electronic component of the compressor, the integrated housing extending towards the inner wall.

A bearing system includes a bearing housing and a foil bearing assembly. The bearing housing includes a sleeve that defines a cylindrical bore and includes at least one bearing assembly locking feature, and a mounting structure. The foil bearing assembly includes an outer foil assembly, an inner foil assembly, and a bump foil assembly positioned between the outer foil assembly and the inner foil assembly. The outer foil assembly includes at least one outer foil pad that extends circumferentially from a first end including a bearing retention feature to a second end. The bearing retention feature is cooperatively engaged with the at least one bearing assembly locking feature. The inner foil assembly includes a plurality of circumferentially-spaced inner foil pads. Each inner foil pad extends circumferentially from a tab to a free end. At least one inner foil pad is welded to the outer foil assembly along the tab.

A bearing system includes a bearing housing and a foil bearing assembly. The bearing housing includes a sleeve that defines a cylindrical bore and includes at least one bearing assembly locking feature, and a mounting structure. The foil bearing assembly includes an outer foil assembly, an inner foil assembly, and a bump foil assembly positioned between the outer foil assembly and the inner foil assembly. The outer foil assembly includes at least one outer foil pad that extends circumferentially from a first end including a bearing retention feature to a second end. The bearing retention feature is cooperatively engaged with the at least one bearing assembly locking feature. The inner foil assembly includes a plurality of circumferentially-spaced inner foil pads. Each inner foil pad extends circumferentially from a tab to a free end. At least one inner foil pad is welded to the outer foil assembly along the tab.

An aerator for aerating water comprises a distribution system for distributing air below the water surface and a compressor with an air inlet and at least one air outlet. The compressor is configured to be placed below the water surface. The infiltration of water at the air inlet is prevented by an intake pipe with one open end above the water surface and the other open end has a watertight connection to the compressor. The distribution system has a watertight connection to the air outlet and, due to its nature or by at least one valve, can hold back water. The housing is in thermal contact with the water to cool the compressor. The compressor is a centrifugal compressor that comprises an impeller that is driven by a shaft that it is mounted on air bearings, magnetic bearings or both.

An electric compressor includes a housing; a rotary shaft; an impeller connected to at least a first end portion of the rotary shaft in an axial direction of the rotary shaft, of the first end portion and a second end portion of the rotary shaft in the axial direction; and a pair of air bearings supporting the rotary shaft such that the rotary shaft is rotatable relative to the housing. A load on the first end portion is larger than a load on the second end portion. The pair of air bearings includes a first air bearing, and a second air bearing supporting the rotary shaft at a position closer to the second end portion of the rotary shaft than the first air bearing is. A load carrying capacity of the first air bearing is larger than a load carrying capacity of the second bearing.

An electric compressor includes a housing; a rotary shaft; an impeller connected to at least a first end portion of the rotary shaft in an axial direction of the rotary shaft, of the first end portion and a second end portion of the rotary shaft in the axial direction; and a pair of air bearings supporting the rotary shaft such that the rotary shaft is rotatable relative to the housing. A load on the first end portion is larger than a load on the second end portion. The pair of air bearings includes a first air bearing, and a second air bearing supporting the rotary shaft at a position closer to the second end portion of the rotary shaft than the first air bearing is. A load carrying capacity of the first air bearing is larger than a load carrying capacity of the second bearing.