Research On Key Technologies For Long-life Boundary Lubrication Of Space Mechanism

With the continuous development of space technology,the lifetime requirements of spacecraft on orbit are getting longer and longer,and space mechanism is the key to the long lifetime reliable operation of spacecraft.With the rise of deep space exploration such as manned moon landing and Mars exploration,the environmental conditions of space mechanisms become worse.The reasonable selection of space lubricants and the long-life lubrication design of space mechanism affect each other.Long lifetime operation of the space mechanism on orbit is critical.This thesis takes the long lifetime reliable operation of space mechanisms under boundary lubrication as the research goal,and studies boundary lubrication characteristics of lubricants that affect the life of space mechanisms.Three lubrication methods of space mecahnism include solid lubrication,liquid lubrication,and solid-liquid composite lubrication.The main work and innovations of the thesis are as follows:?1?The boundary lubrication characteristics of RP4751,RP4752 and RIPP4758liquid lubricants in space under vacuum environment are studied,analyze the lubrication lifetime,reciprocating sliding friction characteristics and their influencing factors under boundary lubrication conditions.Finally,it provides quantitative data for the long lifetime lubrication evaluation of space rotating mechanism.The long lifetime lubrication performance evaluation method of space liquid lubricant can be used to evaluate lubrication performance of other space liquid lubricants.?2?The boundary lubrication characteristics of Mo S₂/815Z,Mo S₂/RP4751 and Mo S₂/RIPP4758 three solid-liquid composite lubrication are studied.Mo S₂/815Z and Mo S₂/RIPP4758 solid-liquid lubrication combine the advantages of solid-liquid lubricant in the friction process,which is beneficial to the formation of dual transfer film and boundary lubricant film.The wear debris of the Mo S₂film in the Mo S₂/815Z and Mo S₂/RIPP4758 composite lubrication plays an important secondary lubrication role.This effectively improves the bearing capacity of the friction surface,stable lubrication performance of the composite lubrication and good wear resistance has an important role.The compound of Mo S₂film and RP4751 liquid lubricant can not combine the advantages of solid and liquid lubricants well,and it is not easy to form an effective dual transfer film and boundary lubrication film during the friction process,so that the film is consumed in a short time.The oil-free state on the friction surface will eventually lead to the rapid increase of friction coefficient and lubrication failure for the Mo S₂/RP4751 composite lubrication.?3?The long lifetime lubrication technology of the Infrared Earth Sensor?IES?scanning motor under boundary lubrication is studied.Focus on analysis of scanning motor bearing lubrication status,liquid lubricant supply mechanism,volatility analysis and protective measures,bearing surface treatment.A physical circulation model of oil and gas molecules of scanning motor is established to study the space evaporation loss of the liquid lubricant.TCP surface treatment process for rolling bearings is proposed,the liquid lubricant supply capacity of the motor bearings is evaluated.The evaluation results show that liquid lubricant supply capacity of the motor fulfill the requirements of the motor 8 year's life.?4?In order to verify spaces long lifetime lubrication reliability of different liquid lubricated scanning motors,1:1 ground reliability life tests are carried out on multiple scanning motors lubricated by RIPP4854,RP4751,RP4752 and RIPP4758 liquid lubricant.The results show that RIPP4854,RP4751,RP4752 and RIPP4758 liquid lubricants can fulfill long lifetime lubrication requirements of scanning motors.The lifetime test results of scanning motors can be used for other space mechanisms which under boundary lubrication.?5?In order to verify whether the solid lubricating tiny bearing can meet the lifetime requirements of the IES's calibration component,the reliability lifetime test of the Mo S₂solid lubrication calibration components under the reciprocating swing condition are carried out.Two calibration components have done 5.38×10⁵cycles in the ground lifetime test,which shows that the lifetime of the calibration components can meet 10 years on-orbit life requirements of the IES.The calibrated component's lifetime test method and results can provide test reference for other solid lubricating space mechanisms.