A ball bearing includes an inner ring (1), an outer ring (2), and a ball (3). The inner ring (1) has an inner ring groove curvature radius Ri. The outer ring (2) has an outer ring groove curvature radius Re. The ball (3) has a ball diameter Dw. The ratio of the outer ring groove curvature radius Re to the ball diameter Dw satisfies: Re/Dw0.5275; and/or the ratio of inner ring groove curvature radius Ri to the ball diameter Dw satisfies: 0.5175Ri/Dw0.55. The ball bearing may be accommodated in a housing, thereby forming a ball bearing assembly.

A component of a gas foil bearing, having a plurality of material layers forming a composition gradient that defines a first coefficient of thermal expansion (CTE) and a second CTE that differs from the first CTE, wherein: the plurality of material layers include at least two dissimilar metals, plastics, or fiber filled metals or plastics, that are layered on top of each other; when the component is subject to heating, the component changes from a first shape to a second shape; and the component is a bearing sleeve.

A component of a gas foil bearing, having: a plurality of materials forming a composition gradient that defines a first coefficient of thermal expansion (CTE) and a second CTE that differs from the first CTE, wherein: the plurality of materials include one or more of different metals, plastics, or fibers; and the plurality of materials is formed with fluid or gas filled voids, so that when the component is subject to selected heating, the fluid or gas filled voids increase in temperature and the component changes from a first shape to a second shape.

A component of a gas foil bearing, having a plurality of material layers forming a composition gradient that defines a first coefficient of thermal expansion (CTE) and a second CTE that differs from the first CTE, wherein the plurality of material layers include at least two dissimilar metals, plastics, or fiber filled metals or plastics, that are layered on top of each other, and wherein when the component is subject to heating, the component changes from a first shape to a second shape, and wherein the component is a bump foil.

A component of a gas foil bearing, having: a plurality of material layers forming a composition gradient that defines a first coefficient of thermal expansion (CTE) and a second CTE that differs from the first CTE, wherein: the plurality of material layers include at least two dissimilar metals, plastics, or fiber filled metals or plastics, that are layered on top of each other; when the component is subject to heating, the component changes from a first shape to a second shape; and the component is a top foil.

A steel material for a torsionally stressed component, such as a driveshaft, having a minimum tensile strength of 800 MPs, and the microstructure consists of more than 50 vol. % of bainite, having an alloy with the following composition in wt. %: C: 0.02 to 0.3; Si: up to 0.7; Mn: 1.0 to 3.0; P: max. 0.02; S: max. 0.01; N: max. 0.01; Al: up to 0.1; Cu: up to 0.2; Cr: up to 3.0; Ni: up to 0.3; Mo: up to 0.5; Ti: up to 0.2; V: up to 0.2; Nb: up to 0.1; B: up to 0.01; where 0.02Nb+V+Ti0.25, residual iron, and smelting impurities. The steel material is inexpensive and has good torsional fatigue strength when used for a torsionally stressed component. The invention also relates to a method for producing a component made of the material and to such a component.

A propeller shaft assembly for an aircraft engine includes a shaft having: an annular wall extending circumferentially about a shaft axis and circumscribing a hollowed interior defining a cavity in a front end portion of the shaft, the annular wall having an outer surface and an inner surface facing radially inwardly to the cavity; and a front flange projecting radially outwardly from the annular wall. The front flange includes a hub side surface defining an interface plane and adapted to abut with a propeller hub. The shaft also includes a reinforcement web defining an end wall of the cavity, the reinforcement web extending radially inwardly from the inner surface of the annular wall. At least part of the reinforcement web is radially aligned with the front flange. At least one perforation extends axially through the reinforcement web.

Roller cone drill bits and methods of increasing the wear resistance of a roller cone drill bit are disclosed. The roller cone drill bit includes a plurality of rolling elements within a bearing assembly of a cone. Each rolling element of the plurality of rolling elements may have a surface hardness of HRC 59-63, a hardened depth that is 0.5 mm to 3.0 mm deep, and may be derived from a low carbon bearing steel material. The hardened depth is measured from the surface of each rolling element and the low carbon bearing steel material has, by weight percent, from 0.12% to 0.25% carbon.

A sealing arrangement for a wheel bearing includes a carrier element connectable to a first bearing part of the wheel bearing, a resilient sealing element, and a counterflow plate connectable to a second bearing part of the wheel bearing. The resilient sealing element includes a resilient main body arranged on the carrier element, first and second axial sealing lips extending away from the resilient main body, and a radial sealing lip extending away from the resilient main body. The counterflow plate is arranged with one side facing the carrier element such that the first and second axial sealing lips, and the radial sealing lip, are in sliding contact with the counterflow plate. The first axial sealing lip, second axial sealing lip, and radial sealing lip rest against the counterflow plate with respective contact pressures.

A rigid connecting portion for mechanical coupling of at least a first and second components includes at least one opening; a longitudinal center axis with a center point assigned to the opening; at least one end region in which the opening is arranged; an outer boundary surface at least partially surrounding the opening; and an inner boundary surface configured such that the opening is entirely bounded in a radial direction by the inner boundary surface, the inner and outer boundary surfaces arranged at a distance from each other such that the connecting portion partially surrounds the opening in a ring-like manner with a varying ring thickness.