In many gas turbine engines, a low pressure spool includes a low pressure turbine that is connected to and drives a low pressure compressor, and a high pressure spool includes a high pressure turbine that is connected to and drives a high pressure compressor. Air is compressed by the compressors and communicated to a combustor section where air is mixed with fuel and ignited to generate a high pressure exhaust gas stream that expands through the turbines. Energy is extracted from the turbines to drive the compressors. The spools are mounted for rotation about an engine central longitudinal axis relative to an engine static structure via several bearing systems. The bearing systems are located within bearing compartments that include heat shields to protect components from the high temperatures of the exhaust gases.
The heat shields are typically comprised of sheet metal plates that are attached to the engine static structure with bolts. Due to the thinness of the plates, the bolts can potentially damage areas of the heat shield that come into contact with the head of the bolt during installation. This increases maintenance costs as the shields have to be replaced during overhaul service operations. Riveted-on nut plates are not preferred in hot sections of the engine because threads can seize and pull apart anti-rotation features on the plates requiring them to be drilled out. Another proposed solution is to use thicker mount flanges that are welded to the shields; however, this increases cost and weight.