Analysis On Temperature Field For Gears With Solid Lubricant Coating

Gear transmission has been widely used in modern industry because ofits advantages as accurate transmission ratio,high transmission efficiency,constant power,safe and reliable.Under heavy loadand high-speed condition,the gear tooth surface temperature is exorbitant caused by friction heat and meshing tooth surfaces can’t form effective lubricating oil film,causing the bond failure of tooth surface.At the same time, the high Gear temperature can lead to excessive thermal deformation,causing heat stress,even can eliminate tooth flank transmission clearance.Traditional lubricant oil(or grease) can hardly meet the lubrication requirements of gears operating under special and extreme circumstances such as high temperature,high vacuum,high load and strong radiation,thus the solid lubrication technology is developed and applied to gear drive.In order to meet the needs of the overloading and high-speed gear transmission, the paper adopts theory of gear meshing, heat transfer theory, tribology, surface engineering, heat transfer and thermal analysis techniques and FEM to research gear temperature field and friction and wear mechanisms of high speed and heavy load gear coating,in order to apply solid lubrication composite coating, with low friction and anti-scuffing, on gear surface successfully to meet the critical demands imposed on functionality and performance of gear transmission, many theory and experiment study have been done. The concrete research works include:① According to the basic knowledge of heat transfer, the partial differential equation of heat conduction is deduced, discusses the gear heat balance equation of steady state temperature field of ontology and the establishment of the boundary conditions; Based on Hertz contact theory, the paper analyzes the meshing gear pair in the process of the relative sliding velocity and the changing rule of the hertz contact stress; studies the convection heat transfer coefficient of gear end face and surface area under lubrication condition.② Establish gear temperature field finite element analysis model, calculate the tooth surface friction heat input and convective heat transfer coefficient of thermal physical parameters, etc. Apply the finite element analysis software ANSYS to get the temperature field distribution. Change different transmission parameters of gears, such as load, speed, friction coefficient, analyzed the impact of these parameters on gear steady-state temperature field of ontology and systematically discussed the impact characteristics of gear temperature field of ontology.③ In order to apply the sulfurizing coating to power transmitting gears, coating are deposited on bearing balls. Friction and wear tests are performed using a MRS-1J test rig. the friction coefficient and grinding spot diameter of different friction pair are obtained. Studied the friction and wear properties of base balls and coated steel balls under the conditions of grease lubrication and oil lubrication. Optical microscopy and X-ray photoelectron spectrometer are used to observe the surface of coating and wear scar to analyze the wear mechanisms. The results show that Fe S coatings havebetter friction and wear performance under the condition of lubrication. The main wear mechanism of coating is abrasive wear and peeling.