Experimental Study Of Traction Characteristics Of Low-speed Grease For Sliding Bearing On Construction Machinery

In recent years, with the rapid development of modern industry, the tribology inindustrial applications has been received a great deal of attention and promotion，andthe research on the traction characteristics of the elastohydrodynamic lubrication (EHL)has been paid more and more attention. In the dynamic design of modern bearing, asone of the basic elements of sliding bearing，lubricant has become an important factorthat affects the dynamic performance and service life of the bearing. Therefore, thetraction characteristic of lubricant in the dynamic design of sliding bearing has becomean indispensable reference. However, The oil film on the surface of the contact is verythin in low speed and heavy load applications，so the shear stress of the oil film isvery large and rheological effect is obvious. Moreover, a variety of factors such asthe working conditions of bearing,the thermal effects, the instantaneous effect of thecontact region and the rheological properties of lubricant will lead to a complicatedvariety of the traction characteristics of the lubricant， so there will be manydifferences between pure theory of EHL and actual conditions and it will be difficult tomeet the designer’s need for lubricant traction characteristic data.Therefore, thetraction characteristic test under simulated working condition and theoretical researchon the traction characteristic has an important practical significance in the design ofthe sliding bearing and lubrication performance.In order to meet the requirements of traction characteristics experiment on specialgrease under low speed conditions, the test rig designed by ourselves was improved.Advanced3Moly calcium sulfonate complex grease and Desert Gold complex lithiumgrease, which are used for foreign construction machinery were tested on the improvedtest rig under the conditions of various speeds, loads and temperatures. Through thetest and analysis, the lubrication performances of the two grease for low-speed slidingbearing were assessed. The traction characteristics of the Desert Gold grease andAdvanced3Moly grease were summarized. Besides, their advantages and disadvantages were analyzed and the results are satisfactory. the tractioncharacteristics of the Desert Gold grease and Advanced3Moly grease weresummarized, which has direct guidance for its use in the low-speed sliding bearing ofengineering machinery. The research shows that Desert Gold grease’s tractioncoefficient is small at room temperature and the traction coefficient maintains stabilitywhen the grease working at high temperature, in addition, the grease shows a greatlubrication, especially at low speed and high load. Desert Gold grease has a goodperformance at high and low temperature and can work efficiently in a widetemperature range. Advanced3Moly grease has a stable performance and excellentlubricating effect in medium load, but it is sensitive to the change of load, so itstolerance to shock and changing load can be worse than the former.This thesis completed a part of research task cooperated with The AmericaCaterpillar engineering machinery company in the traction characteristics of low-speed sliding bearing grease and provided an important reference for the tribologydesign of low-speed sliding bearings and related grease in the future.