A wave bearing of a space strain wave gearing device comprises an inner ring formed from a bearing steel, an outer ring formed from a martensitic stainless steel, and balls formed from ceramics. On the inner ring formed from a bearing steel, a ceramic coating formed by an AD method is formed as a rust-preventive coating. In the space strain wave gearing device that adopts solid lubrication (powder lubrication), it is possible to reliably prevent rust from developing on the inner ring formed from a bearing steel of the wave bearing. In a space environment where the temperature greatly changes, appropriate setting of the linear expansion coefficients of the inner ring, the outer ring, and the balls enables a change in the radial gap of the wave bearing to be suppressed to a range that does not interfere with practical use.

Methods and apparatuses are described to increase emissivity within a gearbox. Loss-of-lube conditions can cause a gearbox in a vehicle to quickly heat up and fail, which could lead to loss of aircraft and/or life. Surface treatments within a gearbox, such as black paint, black oxide coatings, shot-peening, and others, can increase emissivity within the gearbox. The increased emissivity can increase heat transfer via radiation, leading to longer operational capabilities during loss-of-lube conditions.

A component includes a metallic substrate having a tribological surface and a coating. The coating includes a first layer disposed on the tribological surface and a second layer disposed on the first layer. The first layer includes titanium, chromium, or a diamond-like carbon (DLC). The second layer includes a disulfide.

A strain wave gearing (1) has a hollow input shaft (5). A wave generator (4), which makes an externally toothed gear (3) flex in the radial direction so as to engage an internally toothed gear (2), has a wave bearing (43) that has a ball retainer (47). An input-shaft outer circumferential surface portion of the hollow input shaft (5) that is positioned on the inside of the externally toothed gear (3) is coated with an oil-repellent coating (14). The surface of the ball retainer (47) is also coated with an oil-repellent coating (15). The oil-repellent coatings (14, 15) lower the grease stirring resistance of the hollow input shaft (5) and the ball retainer (47) and make it possible to reduce loss torque at the strain wave gearing (1).