多种润滑条件下空间机构用球轴承摩擦力矩试验研究
发布时间:2018-10-08 20:49
【摘要】:球轴承运转灵活,摩擦力矩小,应用广泛,在空间机构中较为常见,但这些优点只有润滑合理时才存在,否则容易出现摩擦力矩增大、不稳定甚至轴承卡死的情况。空间的真空环境使得润滑十分困难,因此需要在真空中针对球轴承摩擦力矩展开研究。国内外关于空间摩擦学、球轴承摩擦力矩的研究有不少,但针对空间机构用球轴承摩擦力矩的研究并不多见。针对这种情况本文做了以下工作: 搭建了可以提供真空及温度环境的摩擦力矩实验系统。对空间润滑方式进行了探讨,选择MoS2膜润滑、PFPE(全氟聚醚)脂润滑以及二者结合的混合润滑作为润滑条件,以无润滑的情况作为对照。分析空间环境对球轴承的摩擦力矩的影响,选取真空度、温度为关键因素,另外选取转速、载荷等作为实验因素,测试了球轴承的摩擦力矩,对其磨损机理进行了分析。 本文对球轴承进行了摩擦力矩实验,结果表明:MoS2膜润滑球轴承启动容易;摩擦力矩小且稳定,真空中要比大气下小许多,,对温度不太敏感,随转速升高先增大后减小,随载荷线性增长。无润滑球轴承摩擦力矩大且波动大;通常对温度、转速也不太敏感,但当温度、转速稍高时会急剧增大;通常随载荷线性增长,但在真空中重载下时会急剧增大。有脂润滑球轴承启动摩擦力矩较大,磨合期长,真空中比大气下稍大。PFPE脂润滑球轴承摩擦力矩随温度升高而减小,随载荷增加先略有减小后线性增大,随转速升高先增大后减小。添加1.5%纳米SiO2颗粒改性的PFPE脂润滑球轴承摩擦力矩一般要比PFPE脂润滑球轴承的要小,在低温、重载时特别明显。摩擦力矩随温度的升高而持续减小,随载荷或转速的增大均是先略有增大后持续减小。混合润滑球轴承的摩擦力矩温度特性与PFPE脂润滑球轴承的类似,摩擦力矩转速特性、载荷特性与改性的PFPE脂润滑球轴承的一致。通过SEM照片及能谱分析结果可知:固体膜润滑球轴承的MoS2复合润滑膜破坏严重,但基体磨损轻微;无润滑球轴承的磨损非常严重;PFPE脂润滑球轴承、采用纳米SiO2改性的PFPE脂润滑球轴承磨损轻微,其中后者更轻;混合润滑球轴承的MoS2膜的破坏也很严重,基体磨损轻微。 综合分析认为:在空间机构中,当载荷小、寿命要求短,宜选用固体膜润滑球轴承;当载荷较大、寿命要求长时,宜选用合适的脂润滑球轴承。
[Abstract]:Ball bearings are flexible in operation, small in friction torque, widely used in space mechanisms, but these advantages only exist when lubrication is reasonable, otherwise, friction torque will increase, instability and even bearing stuck. The vacuum environment in space makes lubrication very difficult, so it is necessary to study the friction moment of ball bearing in vacuum. There are many researches on space tribology and ball bearing friction moment at home and abroad, but there are few researches on space mechanism ball bearing friction torque. In this paper, the following work has been done: a friction torque experimental system which can provide vacuum and temperature environment is set up. The space lubrication mode was discussed. The MoS2 film lubrication and the combined lubrication were selected as the lubrication conditions, and the non-lubricating condition was used as the contrast. The influence of space environment on the friction torque of ball bearing is analyzed. The vacuum and temperature are selected as the key factors, and the rotational speed and load are selected as experimental factors. The friction moment of ball bearing is tested and the wear mechanism is analyzed. In this paper, friction torque experiments of ball bearings are carried out. The results show that it is easy to start up with the W MoS2 film lubricated ball bearings, the friction torque is small and stable, the vacuum is much smaller than that in the atmosphere, and is not very sensitive to temperature, and increases first and then decreases with the increase of rotational speed. It increases linearly with the load. The friction torque of unlubricated ball bearings is large and fluctuating; usually it is not sensitive to temperature and rotational speed, but it will increase sharply when temperature and rotational speed are slightly higher; usually, it will increase linearly with the load, but it will increase sharply under heavy load in vacuum. The friction torque of grease lubricated ball bearing is larger than that of atmosphere, and the friction torque of grease lubricated ball bearing decreases with the increase of temperature, and decreases slightly with the increase of load, and then increases linearly with the increase of load. With the increase of rotational speed, it first increases and then decreases. The friction torque of PFPE grease lubricated ball bearing modified by 1.5% nanometer SiO2 particles is generally smaller than that of PFPE grease lubricated ball bearing, especially at low temperature and heavy load. The friction torque decreases continuously with the increase of temperature, and then decreases with the increase of load or rotational speed. The friction torque temperature characteristics of hybrid lubricated ball bearings are similar to those of PFPE grease lubricated ball bearings. The friction torque rotational speed characteristics and load characteristics of hybrid lubricated ball bearings are identical to those of modified PFPE grease lubricated ball bearings. The results of SEM photos and energy spectrum analysis show that the MoS2 composite lubricating film of solid film lubricated ball bearings is seriously damaged, but the matrix wear is slight, the wear of unlubricated ball bearings is very serious than that of PFPE-lubricated ball bearings. The wear of PFPE grease lubricated ball bearing modified by nanometer SiO2 is slight, the latter is lighter, and the damage of MoS2 film of mixed lubricated ball bearing is very serious, and the wear of matrix is slight. The comprehensive analysis shows that solid film lubricated ball bearings should be selected when the load is small and the life requirement is short in space mechanism, and the suitable grease lubricated ball bearings should be selected when the load is large and the life requirement is long.
【学位授予单位】:哈尔滨工业大学
【学位级别】:硕士
【学位授予年份】:2012
【分类号】:V423;TH133.3
[Abstract]:Ball bearings are flexible in operation, small in friction torque, widely used in space mechanisms, but these advantages only exist when lubrication is reasonable, otherwise, friction torque will increase, instability and even bearing stuck. The vacuum environment in space makes lubrication very difficult, so it is necessary to study the friction moment of ball bearing in vacuum. There are many researches on space tribology and ball bearing friction moment at home and abroad, but there are few researches on space mechanism ball bearing friction torque. In this paper, the following work has been done: a friction torque experimental system which can provide vacuum and temperature environment is set up. The space lubrication mode was discussed. The MoS2 film lubrication and the combined lubrication were selected as the lubrication conditions, and the non-lubricating condition was used as the contrast. The influence of space environment on the friction torque of ball bearing is analyzed. The vacuum and temperature are selected as the key factors, and the rotational speed and load are selected as experimental factors. The friction moment of ball bearing is tested and the wear mechanism is analyzed. In this paper, friction torque experiments of ball bearings are carried out. The results show that it is easy to start up with the W MoS2 film lubricated ball bearings, the friction torque is small and stable, the vacuum is much smaller than that in the atmosphere, and is not very sensitive to temperature, and increases first and then decreases with the increase of rotational speed. It increases linearly with the load. The friction torque of unlubricated ball bearings is large and fluctuating; usually it is not sensitive to temperature and rotational speed, but it will increase sharply when temperature and rotational speed are slightly higher; usually, it will increase linearly with the load, but it will increase sharply under heavy load in vacuum. The friction torque of grease lubricated ball bearing is larger than that of atmosphere, and the friction torque of grease lubricated ball bearing decreases with the increase of temperature, and decreases slightly with the increase of load, and then increases linearly with the increase of load. With the increase of rotational speed, it first increases and then decreases. The friction torque of PFPE grease lubricated ball bearing modified by 1.5% nanometer SiO2 particles is generally smaller than that of PFPE grease lubricated ball bearing, especially at low temperature and heavy load. The friction torque decreases continuously with the increase of temperature, and then decreases with the increase of load or rotational speed. The friction torque temperature characteristics of hybrid lubricated ball bearings are similar to those of PFPE grease lubricated ball bearings. The friction torque rotational speed characteristics and load characteristics of hybrid lubricated ball bearings are identical to those of modified PFPE grease lubricated ball bearings. The results of SEM photos and energy spectrum analysis show that the MoS2 composite lubricating film of solid film lubricated ball bearings is seriously damaged, but the matrix wear is slight, the wear of unlubricated ball bearings is very serious than that of PFPE-lubricated ball bearings. The wear of PFPE grease lubricated ball bearing modified by nanometer SiO2 is slight, the latter is lighter, and the damage of MoS2 film of mixed lubricated ball bearing is very serious, and the wear of matrix is slight. The comprehensive analysis shows that solid film lubricated ball bearings should be selected when the load is small and the life requirement is short in space mechanism, and the suitable grease lubricated ball bearings should be selected when the load is large and the life requirement is long.
【学位授予单位】:哈尔滨工业大学
【学位级别】:硕士
【学位授予年份】:2012
【分类号】:V423;TH133.3
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