Abstract: A fuel pump assembly for a gas turbine engine includes a shaft for transmitting motion, a gear connected to and coaxial with the shaft with the gear having a first wear surface, a first bearing coaxial with the shaft with the first bearing being configured to support the gear and having a second wear surface positioned to interact with the first wear surface, and a plurality of indents. The indents are distributed in the first wear surface or the second wear surface and at least two of the plurality of indents are partially aligned in a radial direction.

Abstract: A variable displacement pump can include a rotor having a plurality of vanes, a cam ring surrounding the rotor and vanes, the vanes configured to extend from the rotor and contact an inner cam surface of the cam ring, and a retainer configured to contact the cam ring and to move the cam ring relative to the rotor to modify a pumping action. The pump can also include a direct actuation mechanism configured to control a position of the retainer to control a position of the cam ring and the pumping action.

Abstract: Apparatus and associated methods relate to monitoring health of a hydraulic system. A method includes monitoring pressure within the system and determining when a potential fatigue condition may occur based on counting the number of times pressure in the system has exceeded the at least one threshold. In some embodiments, strain cycle data is calculated based on a time sequence of signals generated by a hydraulic fitting, which is indicative of strain of the hydraulic fitting. An output signal indicative of the fatigue condition determined is generated. In some embodiments, the strain data includes a number of strain cycles that the time sequence of signals crosses from below a strain threshold to above the strain threshold.

Abstract: A dual vane pump system includes first and second vane pumps having first and second rotors with a plurality of vanes moving radially inwardly and outwardly of the first and second rotors, and into contact with an inner surface of the first and second outer liners. A first pre-pressurization passage connects a first pump inlet in the first pump that is at discharge pressure to a second pump outlet in the second pump which is upstream of the second discharge opening. There is a coupling connecting the first and second rotors for rotation together. The pre-pressurization passage extending through the bearing.

Abstract: A method can include receiving, at a control module, first pump characteristic data from a data source associated with a pump, sensing second pump characteristic data from a flow system using one or more sensors, comparing the first pump characteristic data to the second pump characteristic data sensed in the flow system, and determining a health of the pump based on the comparison of the first pump characteristic data to the second pump characteristic data.

Abstract: A gear for a pump includes a gear body defining a root circle, and a plurality of gear teeth extending from the gear body radially outwardly of the root circle. Each of the plurality of gear teeth have a tip portion, a leading edge, a trailing edge, a circular thickness defined between the leading edge and the trailing edge, a first radially outwardly facing surface and a second radially outwardly facing surface. At least one of the first radially outwardly facing surface and the second radially outwardly facing surface includes a chamfered portion that extends from the leading edge toward the trailing edge across a portion of the circular thickness.

Abstract: A dual vane pump system includes first and second vane pumps having first and second rotors with a plurality of vanes moving radially inwardly and outwardly of the first and second rotors, and into contact with an inner surface of the first and second outer liners. A first pre-pressurization passage connects a first pump inlet in the first pump that is at discharge pressure to a second pump outlet in the second pump which is upstream of the second discharge opening. There is a coupling connecting the first and second rotors for rotation together. The pre-pressurization passage extending through the bearing.

Abstract: A method can include receiving, at a control module, first pump characteristic data from a data source associated with a pump, sensing second pump characteristic data from a flow system using one or more sensors, comparing the first pump characteristic data to the second pump characteristic data sensed in the flow system, and determining a health of the pump based on the comparison of the first pump characteristic data to the second pump characteristic data.

Abstract: An assembly for a coupling together rotatable components according to an example of the present disclosure includes, among other things, a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft, a gear mounted on an outer diameter of the rotor shaft, a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear, and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion. The projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. A starter assembly and a method of assembly are also disclosed.

Abstract: Apparatus and associated methods relate to monitoring health of a hydraulic system. A method includes monitoring pressure within the system and determining when a potential fatigue condition may occur based on counting the number of times pressure in the system has exceeded the at least one threshold. In some embodiments, strain cycle data is calculated based on a time sequence of signals generated by a hydraulic fitting, which is indicative of strain of the hydraulic fitting. An output signal indicative of the fatigue condition determined is generated. In some embodiments, the strain data includes a number of strain cycles that the time sequence of signals crosses from below a strain threshold to above the strain threshold.

Abstract: A starter for a gas turbine engine includes a rotor shaft rotatable about an axis and includes an inner bore extending from an axial end of the rotor shaft with respect to the axis. A sun gear is on the rotor shaft. A lock nut is received against an axial end face of the sun gear and threadedly engaged with an outer diameter of the rotor shaft. A retainer is positioned to bias the nut against the axial end face and includes a projection portion threadedly engaged with the rotor shaft in the inner bore. A bolt through the projection portion is threadedly engaged with the rotor shaft.

Abstract: A gear pump bearing can include a body sized and shaped to occupy a portion of a pump housing cavity such that a clearance is formed between the body and a pump housing. The gear pump bearing can also include at least one clearance consuming feature extending from an outer surface of the body configured to reduce motion of the body within the pump housing cavity.

Abstract: An assembly for a coupling together rotatable components according to an example of the present disclosure includes, among other things, a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft, a gear mounted on an outer diameter of the rotor shaft, a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear, and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion. The projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. A starter assembly and a method of assembly are also disclosed.

Abstract: Embodiments include an apparatus and techniques for operating an electromagnetic cartridge seal. Embodiments include operating a cartridge seal in one of a plurality of modes, and receiving a signal at a force applying mechanism of the cartridge seal, the force applying mechanism being coupled to a primary sealing component of the cartridge seal. Embodiments also include controlling the force applying mechanism based at least in part on the received signal.

Abstract: A starter for a gas turbine engine includes a rotor shaft rotatable about an axis and includes an inner bore extending from an axial end of the rotor shaft with respect to the axis. A sun gear is on the rotor shaft. A lock nut is received against an axial end face of the sun gear and threadedly engaged with an outer diameter of the rotor shaft. A retainer is positioned to bias the nut against the axial end face and includes a projection portion threadedly engaged with the rotor shaft in the inner bore. A bolt through the projection portion is threadedly engaged with the rotor shaft.

Abstract: A bearing assembly for a gear pump that includes a bearing housing, a bearing, and a biasing member. The bearing housing has a housing bore that extends between a first housing end and a second housing end along a bearing axis. The bearing is disposed within the housing bore. The bearing has an outer diameter extending between a first bearing end and a second bearing end. The biasing member is disposed between the bearing and the bearing housing to apply a biasing load to the bearing.

Abstract: A bearing for a gear pump includes a bearing body defining a bearing bore defined therethrough along an axis for receiving a gear shaft. The bearing bore defines a cylindrical bearing inner diameter surface. The bearing body defines an outer mating surface configured for mounting to another bearing body. A groove is defined in the inner diameter surface along an axial direction relative to the axis to provide clearance for gear journal motion between the inner diameter surface and the gear shaft. The groove is defined in a portion of the inner diameter surface opposite the mating surface.

Abstract: A gear pump bearing can include a body sized and shaped to occupy a portion of a pump housing cavity such that a clearance is formed between the body and a pump housing. The gear pump bearing can also include at least one clearance consuming feature extending from an outer surface of the body configured to reduce motion of the body within the pump housing cavity.

Abstract: A bearing assembly for a gear pump that includes a bearing housing, a bearing, and a biasing member. The bearing housing has a housing bore that extends between a first housing end and a second housing end along a bearing axis. The bearing is disposed within the housing bore. The bearing has an outer diameter extending between a first bearing end and a second bearing end. The biasing member is disposed between the bearing and the bearing housing to apply a biasing load to the bearing.

Abstract: Embodiments include an apparatus and techniques for operating an electromagnetic cartridge seal. Embodiments include operating a cartridge seal in one of a plurality of modes, and receiving a signal at a force applying mechanism of the cartridge seal, the force applying mechanism being coupled to a primary sealing component of the cartridge seal. Embodiments also include controlling the force applying mechanism based at least in part on the received signal.