COMBINAZIONE SOLLECITANTE CUSCINETTI REGGISPINTA DI TURBOMOTORI A GAS

A plurality of openings are provided in a stationary wall of a gas turbine engine aft of the compressor discharge to admit compressor discharge air into a sealed cavity formed between the stationary wall and the rotor of the gas turbine engine. A valve, biased to an open position, is associated with each of the openings so that under low speed conditions some of the compressor discharge air is admitted to the cavity to provide supplementary axial force on the rotor in one direction to prevent crossover under such conditions. Under higher speed conditions the increase in compressor discharge pressure overcomes the force biasing the valve to its open position, thereby causing the valve to close and terminate flow of compressor discharge air to the cavity, terminating the aforementioned supplementary axial force on the rotor. Each of the valves includes a housing surrounding the corresponding opening in the stationary wall and a valve piston within the housing is biased to an open position by open or more belleville springs positioned within the housing.