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 plain bearing, having a bearing base body made from a metallic material, having an intermediate layer made from a metallic material applied onto the bearing base body, and having a plain-bearing layer made from a non-metallic material applied onto the intermediate layer. The intermediate layer is an arrangement of wires or a perforated plate. The arrangement of wires or the perforated plate forms undercuts and the plain-bearing layer is a layer made from polyether ether ketone.

An overlay of a sliding component, such as a sliding component for an engine, may provide a bearing surface against a steel journal, for example. The overlay may include intermetallic particles disposed in a matrix including tin (Sn). The matrix may be formed by electroplating. Examples of intermetallic particles include, but are not limited to, aluminides and nickel aluminides. The matrix may include an electroplated matrix of tin and/or a tin alloy.

Disclosed herein is a sliding member, such as a sliding bearing, including a resin overlay layer having improved conformability. The sliding member includes a bearing alloy layer and a resin overlay layer formed on the bearing alloy layer, wherein the resin overlay layer includes a solid lubricant phase, a binder resin phase, and a cushion phase, and an area ratio of the cushion phase is 0.5% or more but 5.0% or less.

Among other things, a bearing assembly comprising a hybrid coating is provided. A bearing assembly may comprise a substrate having a surface and a hybrid wear resistant coating over the surface of the substrate. In an example, the substrate may be an inner radial bearing and/or and outer radial bearing within a bearing assembly. The hybrid wear resistant coating may comprise a high wear resistant coating and a low wear resistant coating. The high wear resistant coating may comprise a wear resistant matrix over the surface and a set of wear resistant elements within the wear resistant matrix. In an example, wear elements within the set of wear elements may comprise tungsten carbide. The low wear resistant coating may be over a low wear area of the surface. In an example, the low wear resistant coating may be positioned between the first high wear resistant coating and a second high wear resistant coating.

A sliding element for use in an internal combustion engine may include a ferrous base having a peripheral sliding surface covered by a protective surface layer, the protective surface layer including at least one nitride applied via at least one of physical vapour deposition and a nitrided layer. The peripheral sliding surface may have a diamond like carbon (DLC) coating disposed thereon. The coating may include at least one of (a) one or more transition layers composed of WC1-x and (b) an adhesive layer of metallic chromium with a crystal structure. The coating may include an intermediate layer of metal DLC, the metal may be tungsten in a multilayer structure of a-C:H:W and a-C:H, and an outer layer of metal-free DLC.

A valve device includes a body that defines a passage through which a fluid flows, a shaft that is movably supported with respect to the body and defines an axis, a valve element that is fixed to the shaft to open and close the passage; and a cylindrical bearing bush that movably supports the shaft with respect to the body, in which the bearing bush includes a mixed region in which a metal core material and expanded graphite are mixed with each other, and a first expanded graphite region made of only the expanded graphite such that the metal core material is not exposed in an inner circumferential side region in contact with an outer circumferential surface of the shaft.

A bearing pad for a tilting-pad bearing includes a first member having a bearing surface and a second member disposed on a back surface side of the first member. At least one of a back surface of the first member or a front surface of the second member facing the back surface of the first member has a recess for forming a cavity between the first member and the second member. Preferably, the bearing pad further includes a support member disposed on a back surface side of the second member and tiltably supporting the first member and the second member, and the recess is formed over at least a part of an installation range of the support member in a plan view of the bearing pad.

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 titanium alloy spherical sliding bearing includes an inner ring made of an α+β or α type titanium alloy, and having a convex spherical sliding surface region on the outer periphery of the inner ring. The bearing further includes an outer ring in sliding contact with the sliding surface region via a lubricative liner. The sliding surface region contains primary and secondary α crystal grains, and includes an oxygen diffusion layer of which the oxygen concentration is not less than 0.8% by mass, and the hardness of the surface is not less than 550 Hv, and the oxygen concentration continuously decreases with depth from the surface of the sliding surface region.