Compressor rotor structure and methodology for harmonizing compressor aerodynamics and rotordynamics are provided. Disclosed embodiments benefit from a compressor design effective for improving rotordynamics (e.g., stiffer rotor structure) without reducing a usable aerodynamics range of the compressor. This design may involve variation of the rotor structure along the rotor axis to locate respective surfaces defined by respective inlets of the one or more impellers at a varying distance relative to the rotor axis based on respective ratios selected for the configuration of the impeller bodies. This arrangement may be effective for improving rotordynamics while satisfactorily meeting the respective varying aerodynamics requirements at the various compression stages by the impeller bodies.

Rotor structure for a turbomachine, such as a centrifugal compressor, is provided. Disclosed embodiments make use of structural and/or operational relationships (e.g., distinct axially-extending zones in the radially-inner contour of respective impeller bodies configured to balance mass distribution about a rotor axis) designed to control relative radial and/or axial growth between corresponding interface locations along the rotor axis at which corresponding faces of respective hirth couplings mesh with one another. The ability to control relative radial and/or axial growth between corresponding interface locations may be effective for reducing rotor vibration and/or to establish more reliable contact patterns and reduced levels of mechanical stresses and distortion (e.g., angular distortion) at the hirth coupling interfaces.

Rotor structure for a turbomachine, such as a centrifugal compressor, is provided. Disclosed embodiments make use of structural and/or operational relationships (e.g., distinct axially-extending zones in the radially-inner contour of respective impeller bodies configured to balance mass distribution about a rotor axis) designed to control relative radial and/or axial growth between corresponding interface locations along the rotor axis at which corresponding faces of respective hirth couplings mesh with one another. The ability to control relative radial and/or axial growth between corresponding interface locations may be effective for reducing rotor vibration and/or to establish more reliable contact patterns and reduced levels of mechanical stresses and distortion (e.g., angular distortion) at the hirth coupling interfaces.

An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

An electrical submersible well pump assembly has first and second permanent magnet motors. The first motor drive shaft is connected to a coupling that has internal splines for receiving an externally splined end of the second motor drive shaft. Alignment devices rotationally align magnetic poles of the first drive shaft with the magnetic poles of the second drive shaft prior to securing the housings of the first and second motors together. The alignment devices may be a coupling irregularity in the internal splines that is at a controlled orientation relative to the magnetic poles of the first shaft and a shaft irregularity in the external splines that prevents the second drive shaft from fully engaging the coupling unless the shaft irregularity is in a specified rotational position relative to the coupling irregularity.

An impeller assembly includes: a compressor impeller; a flange member in which a shaft is inserted, the flange member having an abutting portion to abut on an upstream-side end surface, in an axis line direction, of the hub, and an impeller-side flange portion provided on an upstream side, in the axis line direction, of the abutting portion and protruding outward in a radial direction; a nut screwed on a tip portion of the shaft so as to hold the flange member between the nut and the end surface of the hub; a rotor of an electric generator or an electric motor, the rotor having a rotor-side flange portion disposed on an opposite to the hub across the impeller-side flange portion; and a fastening member fastening the impeller-side flange portion and the rotor-side flange portion to each other.

Disclosed is a two-piece shaft assembly for a driven turbocharger with a traction drive. The turbo shaft is attached to a turbine and compressor, and is inserted into a traction barrel that has traction surfaces to mate to the traction drive. In this way, the traction drive can be assembled with only the traction barrel, and the turbo shaft can be inserted through the barrel at the end to simplify assembly.

Disclosed is a two-piece shaft assembly for a driven turbocharger with a traction drive. The turbo shaft is attached to a turbine and compressor, and is inserted into a traction barrel that has traction surfaces to mate to the traction drive. In this way, the traction drive can be assembled with only the traction barrel, and the turbo shaft can be inserted through the barrel at the end to simplify assembly.

A method of loading a rotating assembly of a turbocharger can include positioning a swage collar on an end portion of a turbocharger shaft that extends through a through bore of a compressor wheel; applying a pulling force to the end portion of the turbocharger shaft to achieve a desired amount of loading; deforming the swage collar to form a swaged collar fixed to the end portion of the turbocharger shaft; and releasing the pulling force wherein the swaged collar maintains the desired amount of loading.

A method of loading a rotating assembly of a turbocharger can include positioning a swage collar on an end portion of a turbocharger shaft that extends through a through bore of a compressor wheel; applying a pulling force to the end portion of the turbocharger shaft to achieve a desired amount of loading; deforming the swage collar to form a swaged collar fixed to the end portion of the turbocharger shaft; and releasing the pulling force wherein the swaged collar maintains the desired amount of loading.