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Lubrication Characteristics Of Beveloid Planetary Gear Transmission System Under Microgrivity

Posted on:2021-11-08Degree:MasterType:Thesis
Country:ChinaCandidate:J S RongFull Text:PDF
GTID:2492306572469114Subject:Naval Architecture and Marine Engineering
Abstract/Summary:PDF Full Text Request
As a special mechanism,the variable-thickness planetary transmission system is applied to the gear transmission system in the aerospace field.It can realize the decomposition of motion or power,and has the advantages of good speed regulation performance and smooth operation.But it has internal and external meshing,complex structure,internal and external excitation coupling.In order to ensure that it has a more stable operating condition in the microgravity environment and prolong its service life in the track,it is necessary to discuss further the lubrication characteristics of the microgravity environment.In this paper,molybdenum disulfide is used as a solid lubricating material,and based on Hertz contact theory,the bonding strength of the coating thickness is first analyzed.Use the shear stress and equivalent stress on the contact surface or the lubricating film to measure its bonding strength,and explore the film thickness that is most suitable for the microgravity environment.In order to improve the stress gradient in the lubrication process,this problem was solved by changing the elastic modulus of the lubricating film.Obvious results were obtained when the elastic modulus was about 360 MPa.Considering the vacuum environment and alternating temperature in a microgravity environment,we need to perform thermal stress analysis on thickened gears with and without solid lubricant film.Analyze the thermal deformation of the thickened gear system at different temperatures in the range of-200~200 degrees Celsius,and observe its effect on the backlash of the tooth,thus laying a theoretical foundation for the subsequent gear shape.Finally,the frictional heat effect of the gear under dynamic changes and the friction coefficient of molybdenum disulfide at different torques and speeds are analyzed.The relative sliding speed of the system and the friction coefficient of the contact surface are mainly calculated.Due to the particularity of molybdenum disulfide,we found that the solid lubricant film of molybdenum disulfide has a low coefficient of friction whether it is in a vacuum environment or at high s peed,which will allow the planetary mechanism to undertake more important tasks.It can also produce a lower amount of wear and tear,which can extend the life of the thickened planetary transmission system.
Keywords/Search Tags:beveloid gears, planetary transmission system, microgravity, lubrication characteristics
PDF Full Text Request
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