US Patent 11280396 Fire resistant gearbox housing

A gearbox housing includes a set of ribs on an inner surface of a wall portion of the housing. During a fire event, heat received at the outside of the gearbox is transferred to the ribs, which transfer the heat away from the wall portion, in turn resisting the fire. The ribs may transfer the heat to oil, which may flow toward an oil drain. In addition or alternatively, the ribs may transfer the heat to a heat sink of the housing to which they are connected. The ribs may allow a thin region surrounding the ribs to a have a minimum thickness that is thinner than required to pass a fire test, thereby allowing for lighter weight gearbox houses that are still fire resistant.