Study On The Dynamic Factor Of The Heavy Load And High-speed Involute Spur Gear

The aviation industry is a national strategic high-tech industry.Its level of development directly demonstrates the strength of national defense and economic strength,and is of great significance to air transport and national security.Gears are the basic transmission components of aero-engines,and most of the aviation gear transmissions are under the condition of heavy-duty and high linear velocity.The relative high sliding speed of the gear surface of the heavy-duty and high speed line gears in aviation causes the vibration,noise and additional dynamic loads of the gear pair which will affect the safety and stability of the entire transmission system.The long-term theoretical research and engineering practice results show that the engine failure caused by gear failure has largely constrained the development of China’s aviation industry.At present,especially,it is unreasonable to determine the dynamic factor at supercritical speed by using the classical formula in the theoretical design of high linear speed and heavy load gear transmission of aviation.This paper studies the dynamic factor of aircraft gear during the bending strength verification,discusses the mechanism of internal additional dynamic load in the process of aerodynamic involute spur gear meshing transmission,compares the advantages and disadvantages of classical calculation formulas,and proposes an amendment formula of dynamic factor to meet the requirements of aviation spur gear transmission.The actual dynamic response and analysis have important theoretical and reference values for the design of aerospace gears.Major content of the thesis are summarized as follow:1 The mechanism of the dynamic load on the aerospace gear is studied,and the dynamic load impact and the vibration excitation basis are described.The dynamic load coefficient variation law at the supercritical speed is calculated and analyzed.2 The dynamic model of aerospace spur gear pair is established,and the excitation parameters that affect the dynamic load coefficient are analyzed,and the dynamic meshing force is numerically calculated and simulated.3 The inherent characteristics of the vibration of the aerospace gear structure is analyzed and the contact modes with prestress state are calculated.Based on the contact modes,the natural frequency and main vibration mode of the gear pair is discussed,and analyze the influence of the aerospace gear design parameters on the natural frequency.4 Based on the classical dynamic load coefficient calculation method,statistical calculation and data fitting methods are used to obtain the calculation formula of the corrected dynamic factor and validated by an example calculation.