Abstract: A planet gear includes an annular planet gear rim having a constant inner radius along a complete axial length and an outer radius defined as the radial distance to the root of the gear teeth. The annular planet gear rim further has an average rim radius defined at a halfway point between the constant inner radius and the outer radius. The average rim radius and the rim thickness define a ratio including values in a range from and including about 4 to and including about 9. A gear assembly and turbomachine including the planet gear are disclosed.

Abstract: A ring gear having a longitudinal axis includes an annular gear rim. The annular gear rim further includes an inner annular surface and a plurality of teeth extending from the inner annular surface, the plurality of teeth configured to mate with a planet gear of a planetary gear assembly. The annular gear rim further includes a plurality of pin members distributed circumferentially about the annular gear rim, each pin member of the plurality of pin members oriented parallel to the longitudinal axis. The plurality of pin members is configured to couple the annular gear rim to a secondary structure and, when coupled to the secondary structure, to facilitate bending of the annular gear rim when a load is applied to at least a portion of the plurality of teeth by the planet gear.

Abstract: A ring gear having a longitudinal axis includes an annular gear rim. The annular gear rim further includes an inner annular surface and a plurality of teeth extending from the inner annular surface, the plurality of teeth configured to mate with a planet gear of a planetary gear assembly. The annular gear rim further includes a plurality of pin members distributed circumferentially about the annular gear rim, each pin member of the plurality of pin members oriented parallel to the longitudinal axis. The plurality of pin members is configured to couple the annular gear rim to a secondary structure and, when coupled to the secondary structure, to facilitate bending of the annular gear rim when a load is applied to at least a portion of the plurality of teeth by the planet gear.

Abstract: A planet gear includes an annular planet gear ring including an annular planet gear rim. The annular planet gear rim has an inner radius and an outer radius. The inner radius and the outer radius define a rim thickness therebetween. The annular planet gear rim further has a bending stress neutral axis. The bending stress neutral axis radius and the rim thickness define a ratio including values in a range from and including about 3 to and including about 10.

Abstract: A counter rotating helico-axial pump is provided, the pump comprising: (a) an inner rotor comprising a plurality of outwardly extending helico-axial impeller vanes; (b) a hollow outer rotor comprising a plurality of inwardly extending helico-axial impeller vanes; (c) a single driving device configured to drive the inner rotor or the hollow outer rotor; and (d) a force transmission coupling joining the inner rotor and the hollow outer rotor and configured to permit rotation of the inner rotor and hollow outer rotor in opposite directions; wherein at least a portion of the inner rotor is disposed within the hollow outer rotor, and wherein the inner rotor, the hollow outer rotor and the helico-axial impeller vanes define a fluid flow path, and wherein the inner rotor and hollow outer rotor are configured such that at least some of adjacent helico-axial impeller vanes are configured to rotate in opposite directions.

Abstract: A counter rotating helico-axial pump is provided, the pump comprising: (a) an inner rotor comprising a plurality of outwardly extending helico-axial impeller vanes; (b) a hollow outer rotor comprising a plurality of inwardly extending helico-axial impeller vanes; (c) a single driving device configured to drive the inner rotor or the hollow outer rotor; and (d) a force transmission coupling joining the inner rotor and the hollow outer rotor and configured to permit rotation of the inner rotor and hollow outer rotor in opposite directions; wherein at least a portion of the inner rotor is disposed within the hollow outer rotor, and wherein the inner rotor, the hollow outer rotor and the helico-axial impeller vanes define a fluid flow path, and wherein the inner rotor and hollow outer rotor are configured such that at least some of adjacent helico-axial impeller vanes are configured to rotate in opposite directions.