Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

A sliding member includes an overlay layer made of a resin on a side of a sliding surface of a bearing alloy layer. When a valley void volume Vvv (μm.sup.3/μm.sup.2) in the sliding surface of the overlay layer is defined as Vv1, Vv1 is in a range of 0.015≤Vv1≤0.200.

Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

A bearing assembly includes an outer race having an inner surface defining a concave contour and an inner race positioned in the outer race. The inner race has an inner surface defining a bore therethrough and an outer surface defining at least one groove circumscribing the outer surface. A plurality of rolling elements is rollably located in the groove and is in rolling contact with the inner surface of the outer race. A lubricious liner has an inner liner-surface and an exterior liner-surface, the exterior liner-surface being disposed on the inner surface defining the bore. The lubricious liner has a modulus of compression of a magnitude sufficient to allow misalignment of the inner liner-surface relative to the exterior liner-surface in response to a force applied thereto.

It is possible to provide an iron-based sintered sliding material excellent in the sliding performance. Provided is an iron-based sintered sliding material including, a base containing, by mass, 3 to 15% of S, 0.2 to 6% in a total amount of at least one selected from the group consisting of Cr, Ca, V, Ti, and Mg, and a remainder of Fe and inevitable impurities, sulfide particles containing at least one selected from the group consisting of Cr, Ca, V, Ti, and Mg being dispersed in the base, and pores.

Gearboxes for aircraft gas turbine engines, in particular arrangements for journal bearings such gearboxes, and related methods of operating such gearboxes and gas turbine engines. A gearbox for an aircraft gas turbine engine includes: a sun gear; a plurality of planet gears surrounding and engaged with the sun gear; and a ring gear surrounding and engaged with the plurality of planet gears, each of the plurality of planet gears being rotatably mounted around a pin of a planet gear carrier with a journal bearing having an internal sliding surface on the planet gear and an external sliding surface on the pin.

A bearing assembly includes an outer race having an inner surface defining a concave contour and an inner race positioned in the outer race. The inner race has an inner surface defining a bore therethrough and an outer surface defining at least one groove circumscribing the outer surface. A plurality of rolling elements is rollably located in the groove and is in rolling contact with the inner surface of the outer race. A lubricious liner has an inner liner-surface and an exterior liner-surface, the exterior liner-surface being disposed on the inner surface defining the bore. The lubricious liner has a modulus of compression of a magnitude sufficient to allow misalignment of the inner liner-surface relative to the exterior liner-surface in response to a force applied thereto.

Aspects of the disclosure are directed to a rotatable shaft, and a plurality of bearings coupled to the rotatable shaft, where the plurality of bearings include a first bearing, a second bearing, and a third bearing, where the first bearing defines an axial first bearing centerline, where the second bearing defines an axial second bearing centerline, where the third bearing defines an axial third bearing centerline, and where the axial second bearing centerline is radially offset from the axial first bearing centerline and the axial third bearing centerline.

A bearing system for rock mechanics test under high temperature and high pressure multi-field coupling includes a force sensor lifting seat and a jack. The force sensor lifting seat includes a connecting disk connected with the jack, a support disk, and an operation channel. A groove dented downwards is arranged on the connecting disk, the support disk is disposed in the groove and freely propped upon the connecting disk; through holes of the connecting disk and the support disk form a control operation channel; and a limiting device is arranged for preventing an MTS triaxial force sensor from disengaging from the support disk. A bolt hole of the force sensor can be aligned with a mounting hole on a solid steel column by rotating the connecting disk for convenient and accurate bolting.