New methods for identifying diagnostic indicators of the technical condition of aircraft gas turbine engine reduction gearboxes

Abstract

Planetary gearboxes of aviation gas turbine engines are their most stressed units. Control of their technical condition under operating conditions by measuring the oil temperature and the presence of chips in it by a visual endoscopic method does not provide the required completeness of control. High vibration activity of gearboxes, especially in case of development of a widespread defect in the form of wear of tooth flanks, requires additional methods of assessment of their technical condition. The practice of operating such complex and stressed objects shows that vibroacoustic diagnostics is the most effective one. However, for aviation gas-turbine engines its use is connected with certain difficulties. First of all, it is the change of vibration intensity when the engine is relocated from the test bench to the object. At the engine manufacturer's stand, as a rule, the collection of experimental material for the development of methods of vibration-based diagnostics of defects is carried out. To overcome the above-mentioned problem, we suggest new methods for detecting diagnostic signs of tooth flank wear. Both vibration processes and signals of standard tachometric sensors of input and output gearbox shaft rotation frequency are used. A set of diagnostic features on the basis of frequency parameters is proposed. The use of some of them makes it possible to assess the technical condition of the engine gearbox during operation, for example in the performance of routine maintenance work.