The Study Of Mechanical Parts Reliability Under Several Distributions

Reliability is the top quality indexes of military products. The reliability of the product is an important factor of battle effectiveness in troops and it is an important symbol of the national industrial modernization. Gear and bearing are aviation engine accessory machine box key components and carrying on the reliability analysis to them has practical significance.Mechanical reliability analysis of common distribution type is normal distribution, logarithmic normal distribution and weibull distribution. According to the principle of the JC checking-point method realizes three types of distribution under arbitrary combination of reliability calculation. SORM is based on standard space time of FORM. Through the transition matrix, the author realizes the relation between JC method that bases on the original state space time and SORM method.The gears of aviation engine accessory machine box include cylindrical gears and spiral bevel gears. According to GB and HB of the cylindrical gear and HB of the spiral bevel gear, the author established the mathematical model. The reliability sensitivity analysis is an important aspect of the reliability design work and you can grasp the important factors of the reliability design from the result of the reliability sensitivity analysis. Through the improved JC method reliability sensitivity analysis principle, the author realizes the reliability sensitivity analysis of cylindrical gears and spiral bevel gears under arbitrary distribution combination.When the reliability of bearing life is in0.4～0.9, the bearing life obeys two parameters weibull distribution. According to this theory, the author establishes the function equation between reliable life correction coefficient and bearing life reliability under bearing life reliability in0.4～0.9. When bearing life reliability in0.9～1, according to the principle of curve fitting, the author establishes the function between reliable life correction coefficient and bearing life reliability. When not considered the load fluctuation, it calculates bearing life reliability according reliable life correction coefficient. When considered the load fluctuation, it solves bearing life reliability through the JC checking-point method iterations by using the reliable life correction coefficient and bearing life reliability formula. The author calculates traditional and considering the load fluctuation life reliability under mainly focusing on the deep groove ball bearings, angular contact ball bearings and cylinder bearings.The author uses the VC++to program for the whole project and achieves the automatic computation for gears and bearings reliability analysis. If this program is applied in project, it can be greatly save money and time of design, and enhance the efficiency.