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 seal assembly includes a carbon seal that has a sealing surface. A seal seat has a sealing surface and is positioned for rotation relative to the carbon seal. A diamond-like carbon coating at least partially forms the sealing surface on the seal seat.

A sealing arrangement for a shaft according to an example of the present disclosure includes a shaft and a sealing assembly. The sealing assembly includes a seal cartridge that has at least one sealing element. The first and second mating rings are configured to axially locate the seal cartridge with respect to the shaft. The second mating ring includes at least one tang that is configured to extend through at least one corresponding slot in the shaft, the at least one tang is configured to engage a retaining ring to axially retain the second mating ring on the shaft. A gearbox/accessory interface assembly and a method of sealing a gearbox with respect to an accessory are also disclosed.

A centrifugal pump, and components thereof, operable at high speeds, is described under the present disclosure. A hard polymer sleeve can be applied to certain surfaces of a seal casing within the pump. If the sleeve is applied along surfaces near the center shaft, then the hard polymer will withstand the forces and pressures of the system. The hard polymer might not be used along the outer diameter, farther from the shaft, because velocities are higher the further out one goes. The current disclosure allows for the use of fluoropolymer in the lining sleeve. The benefits of fluoropolymer have been unavailable in high speed centrifugal pumps because the forces are too great on the periphery of the seal casing. However, the lower speeds along the interior, near the shaft, allow fluoropolymer to be used.

A rotor assembly for a gas turbine engine according to an example of the present disclosure includes, among other things, a rotor that has a hub carrying one or more rotatable blades. The rotor is mechanically attached to a shaft, and an annular seal is carried by the shaft. The annular seal includes a substrate, a first layer disposed on the substrate, and a second layer disposed on the first layer and arranged to establish a sealing relationship with the rotor. The second layer includes a solid lubricant that has molybdenum trioxide (MoO3). A method of sealing for a gas turbine engine is also disclosed.

A component for a gas turbine engine includes an airfoil. A first trunnion has an outer surface and extends from a first end of the airfoil. A first bushing at least partially surrounds the outer surface. At least one of the first bushing or the first trunnion includes a plurality of surface irregularities.

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 multi-shaft assembly includes an inner shaft and an outer shaft coaxially aligned with the inner shaft to establish a shared axis of rotation. The multi-shaft assembly also includes an ablatable shaft feature with a lubricant surface coating on an interior surface of the outer shaft and an ablatable metallic alloy layer overlaying a portion of the lubricant surface coating with a radial air gap formed between the ablatable metallic alloy layer and an exterior surface of the inner shaft.

A seal structure for a turbocharger, including: a seal ring; a seal groove in which the seal ring is disposed; and a treated portion, which is formed at least at a part of one or both of the seal ring and the seal groove, and is subjected to surface treatment for anti-oxidation.

An abrasive tip comprises an additive layer having an additive; the additive is configured to prevent adhesion of an organic component from an abradable seal onto an abrasive blade tip.