Eccentric And Resonance Of Aviation High-speed Motor Shaft Fatigue Research

In the study of modern shaft’s fatigue and life, what caused by the asymmetry between the two bearing installation error of Angle research there has been a lot and very mature, but due to the vibration and installation error caused by the eccentric shaft end of the shaft fatigue life analysis are very few, and in view of the eccentric and vibration is a common and practical solutions are put forward also very few. So there is of great significance for shaft parts verified resonance and eccentric shaft end influence on fatigue life research. Through to analysising the broken shaft section morphology, fracture texture of this article Got the fracture is mainly due to the eccentric shaft parts, vibration, fracture face while rotating bending moment under the common function.Shear stress rupture properties are torque under the action of formation of the overload fracture. Rotor dynamics analysis was carried out on the motor rotor, the rotor of the third order critical speed is 1565.5 r/min, 22558 r/min and 22765 r/min, compared with the motor speed of 11076 r/min, close to the speed safety margin of 85.8% and 50.9% respectively, were greater than the danger margin 10%, research shows the motor rotor will not happen to resonance caused by the critical speed and rated speed close to effects shaft fatigue life, at the same time, the modal analysis and inherent frequency by modal test analysis verify the accuracy of simulation and test data also shows that the motor won’t impact on shaft fatigue life because of the inherent frequency and resonant. To actual eccentric shaft extension end and theoretical calculation, stress practical limit eccentricity is 0.125 mm, shaft weak stress value is 785.44 mpa, Through ANSYS finite element simulation analysis software of aviation motor spindle condition boundary conditions to simulate the stress analysis was weak place stress on the size of 752 mpa, the accuracy of the calculation results and simulation analysis is verified for the shaft stress design provides reference basis. Refer to manual of aviation materials received 30 Cr Mn Si material fatigue life curve, and 13 stress points on the curve corresponding to the fatigue life cycles, according to the broken shaft stress size and S.N curve fitting get broken shaft fatigue life of 20674 cycles. In eccentric and vibration influence on fatigue life of shaft parts, put forward the bearing under the pre.tightening force and add rubber gasket between bearing and bushing have vibration and the transfer of eccentric fixed end purpose gives shaft parts life greatly improved, and by every 200 hour record motor front.end and back.end, backend method of lateral vibration of motor 1500 hour life experiment was carried out, and the motor parts can still work normally. Through the theory of finite element simulation to compare the shaft’s weak place stress to before and after of the improvement,without rubber ring weak place stress on the shaft of 785.44 mpa, added a rubber ring on the rear shaft weak stress size at 95.78 mpa, shows that under the same eccentric limit of 0.125 mm, bearing and bushing interface slot with rubber ring method for weak axis stress greatly reduced. for the future practical application way to improve the shaft fatigue life research provides a theoretical basis for reference.