| As a new type of cylindrical gear,the cylindrical gear with variable hyperbolic circular-arc-tooth-trace(VH-CATT)has better transmission performance than spur gears,helical gears and double helical gears with the same structural parameters(such as modulus,number of teeth,and pressure angle,etc.),which is suitable for high-speed and heavy-duty conditions.But for high-speed and heavy-duty gear transmissions,tooth surface wear is one of the most basic failure modes,and it is also one of the main reasons for power loss.Therefore,it is of great significance to study the lubrication and wear of this new type of gear under different conditions for prolonging gear life and reducing gear loss.This subject mainly focuses on the study of mixed lubrication characteristics,dry friction and wear characteristics under thermal mixed lubrication of the VH-CATT cylindrical gear.(1)According to the tooth surface equation of the VH-CATT cylindrical gear,a pair of meshing gear pairs are established.Combined with the principle of gear meshing,the principal curvature and induced normal curvature of the VH-CATT cylindrical gear are derived.The main curvatures and induced normal curvatures of the concave and convex surfaces of the VH-CATT cylindrical gear are obtained by numerical calculation,which lays a foundation for the later research.Through the tooth profile equation,the tooth profile shape of each section of the VH-CATT cylindrical gear is analyzed.(2)By simplifying the model of the VH-CATT cylindrical gear,the curvature radius,contact half width and contact pressure of the VH-CATT cylindrical gear are derived,and then the gear wear prediction model of the VH-CATT cylindrical gear under dry friction is established.The rationality of the wear prediction model is proved by comparing the wear calculation models.Through numerical calculation,the wear change of the VH-CATT cylindrical gear is obtained,and the influence of gear design parameters and operating parameters on gear wear is analyzed.(3)Based on the basic equation of mixed lubrication point contact and the transmission characteristics of the VH-CATT cylindrical gear,a prediction model of mixed lubrication for the VH-CATT cylindrical gear is established.The distribution law of pressure and oil film thickness of the VH-CATT cylindrical gear under mixed lubrication is solved by using compound iterative method,and the influence of transmission parameters and design parameters on oil film pressure and oil film thickness is analyzed.(4)Combined with the mixed lubrication prediction model,flash temperature model and modified Archard wear model,the wear prediction model of the VH-CATT cylindrical gear under hot mixed lubrication is established.The wear prediction model is solved by numerical calculation,and the change of wear of the VH-CATT cylindrical gear under hot mixed lubrication is obtained.The influence of gear design parameters and operating parameters on gear wear under hot mixed lubrication is analyzed.Compared with the gear wear under dry friction,the influence of surface roughness and lubricating oil performance on gear wear is further analyzed.The research results of this subject show that good lubrication and high-precision tooth surface can reduce tooth surface wear.Among them,the level of tooth surface accuracy has a greater impact on tooth surface wear.At the same time,through the research of this subject,it can also provide a certain theoretical basis for the failure research and life prediction of the VH-CATT cylindrical gear. |
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