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Study on Wear Life of Momentum Wheel Bearing

Author: LiuLiangYong
Tutor: DengSiEr；LiJianHua
School: Henan University of Science and Technology
Course: Mechanical Design and Theory
Keywords: Momentum wheel Aerospace bearings Wear life Statics analysis Numerical simulation
CLC: V229.2
Type: Master's thesis
Year: 2011
Downloads: 133
Quote: 0
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Abstract


The momentum wheel is important implementing agency of the spacecraft attitude control systems, and miniature precision angular contact bearings is the core component of the momentum wheel. Rotation precision bearings, vibration, friction torque volatility and life performance determines the performance of the spacecraft and mission life. Such bearings are usually working in a high-speed light-load weightless space environment, its main failure mode of such working conditions are insufficient lubricant or failure result in excessive wear of the bearing channel, which led to the bearing vibration, noise and friction torque increases, lower rotational accuracy. Bearing wear life calculation method is and Germany FAG company from fitting Weibull distribution based on the test data of more than two decades ago, only a reference value. Therefore, the establishment of effective momentum wheel bearing wear life calculation model is imperative. In this study, a model momentum wheel bearings, for example, the use of the rolling bearing quasi static analysis methods to calculate the pressure distribution of the ball and channel contact area, sliding velocity distribution, lubrication parameters derived on this basis dispatched amount of wheel bearings based Archard Wear Theory wear rate expression, calculated by geometric analysis in terms of the amount of wear channel radius variation amount, and to analyze the relationship of the amount of change in channel geometry parameter change amount of preload, thereby establishing the wear life of the momentum wheel bearing model; take advantage of the VC programming tool for the preparation of the momentum wheel bearings for wear life calculation software, use the software to analyze the conditions and structural parameters of the bearing wear characteristics; momentum wheel bearing wear life test calculation model of correctness, and take advantage of small sample reliability assessment method momentum wheel bearing wear life reliability. Theoretical analysis and test results show that the wear life of the momentum wheel bearings can be calculated by the amount of preload changes; wear occurs mainly in the channel between the ball and inside and outside, including channel within the wear rate of the channel is probably 13 times the wear rate of the outer channel and outer channel wear can be ignored in the calculation; wear rate increases with increasing preload wear life first increased and then decreased with the increased preload, there is the most excellent value; wear rate with the speed increases with the speed increase wear life reduce wear life impact speed in the lower speed; allowable amount of wear and wear rate with increasing radius of curvature of the intraparietal coefficient fi bearing wear life will increase, f_i take 0.52; As fo the increase, the wear rate increases and decreases wear life.

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CLC: > Aviation, aerospace > Aviation > Aircraft Construction and Design > Aviation mechanical components,standard parts,profiles > Shafts and bearings
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