| In recent years,China’s space industry has developed vigorously.With the increasing of the payload that needs to be sent to space,people put forward the requirements of low cost,high reliability and large carrying capacity.As the foundation and core of the development of space industry,hydrogen and oxygen turbopump of rocket engine is the key to improve the performance of rocket engine.At present,LH2 cryogenic bearing technology is still used in the main shaft bearing of hydrogen and oxygen turbopump of rocket engines in China,while the main engine of the us space shuttle and the oxygen turbopump of Russian rocket take the lead in using hydrogen-gas cooling bearing technology,which simplifies the structure of the turbine pump and significantly improves the performance of the engine.Therefore,it is of great significance to study the key technology of hydrogen-gas cooled bearing,establish the technical system of hydrogengas cooled bearing,simplify the turbo-pump structure of rocket engine,improve the thrust and reliability of rocket engine,and finally improve the international competitiveness of China’s aerospace industry.In this paper,by using the methods of testing,testing and theoretical analysis,select suitable for the hydrogen cooling bearing raceway surface modification of solid lubrication film materials,set up to simulate the hydrogen cooling bearing condition of bearing comprehensive performance test rig,verify the feasibility of solid lubrication for the bearing surface modification,and finally completed the gas hydrogen cooled solid lubrication bearing manufacture.Firstly,a force-thermal comprehensive analysis of air-hydrogen cooled bearing was carried out to calculate the internal stress,relative sliding speed and other parameters of the bearing,so as to provide theoretical basis for subsequent experimental design.Then,the performance analysis of solid lubrication film based on hydrogen-gas cooling bearing condition was carried out to analyze the influence of the thickness,elastic modulus and other parameters of the solid lubrication film on the bearing characteristics of the film,so as to provide a theoretical basis for the selection of modified solid lubrication film on the surface of the bearing raceway.DLC and C-MoS2 films were pre-plated on standard plates of UMT-3,and the components of the films were analyzed by EDS.The inherent mechanical properties of the two solid lubricating films,such as hardness and elastic modulus,were tested by indentation/scratch experiments.The friction coefficient between the ball and disk was tested by the ball-disc friction experiment,and the friction reduction effect and lubrication life of the two kinds of solid lubrication film were compared.The solid lubrication film that meets the requirements of surface modification of the raceway of hydrogen-gas bearing was selected.The scratch morphology of the standard disc surface film was observed by SEM scanning electron microscope,and the failure mode of the film was analyzed.Raman spectroscopy was used to analyze the lubrication mechanism of DLC films under different working conditions,providing a theoretical basis for the practical application of solid lubrication films.Trial to test the service performance of the bearing,the hydrogen cooling was designed and built the hydrogen cooling bearing comprehensive performance test rig,the test bed can simulate the actual working condition of the hydrogen gas cooling bearing,bearing test under the conditions of service performance,can also test the bearing friction torque under axial load,bench top speed can reach 30000 r/min.The LabView data acquisition program is established,which can realize real-time monitoring and feedback of bearing temperature,friction torque,axial load,storage of experimental data,warning and other functions.After that,the correctness of the platform design and the accuracy of friction moment measurement are verified through the platform performance test.The use of hydrogen gas bearing torque measuring instrument performance test rig and BRG-3000 tested under different working conditions of solid lubrication and grease lubrication of the bearing friction torque and the influence of temperature,compared to two kinds of lubrication lubrication anti-friction effect,to verify the feasibility of solid lubrication for the bearing raceway surface modification,finally according to the selected solid lubricating film,manufacture the gas hydrogen cooled solid lubrication bearing. |
