1988 Fiscal Year Final Research Report Summary
Study on Run-out Characteristics and Precision Design Method of Externally Pressurized Gas Bearings
| Project/Area Number |
62550111
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
機械要素
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| Research Institution | Kyoto University |
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Principal Investigator |
YABE Hiroshi Professor, Faculty of Engineering, Kyoto University, 工学部, 教授 (30025936)
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| Project Period (FY) |
1987 – 1988
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| Keywords | Gas Bearing / Externally Pressurized Bearing / Run-out Characteristics / Machining Errors / Bearing Stiffness and Damping Coefficient / Precision Design Method / 表面粗さ |
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| Research Abstract |
1. The characteristics of load-carrying capacity fluctuation, which may results in axial run-out of the rotor, of an externally pressurized thrust collar bas bearing are analyzed theoretically. Two aspects of machining errors of the bearing and the rotor are taken into consideration; one is perpendicularity of the rotor end surface, and the other is the size deviation of the gas supply holes.
2. The fundamental bearing characteristics (bearing stiffness and damping coefficient) are analyzed. The effects of the maching errors of the bearing are investigated, resulting in a qualitative evaluation of the so-called averaging effects.
3. The static and dynamic run-out characteristics of the bearing are clarified in relation with the machining errors of the bearing.
4. Two mathematical models are introduced to evaluate the amplitude of the rotor vibration; simplified linear model and non-linear simulating model. The former is confirmed to be sufficiently accurate to evaluate the run-out characteristics.
5. Experimental results of the run-out of the rotor and the bearing with machining errors confirm the validity of the analytical model and the consequent results.
6. A theoretical model is introduced to evaluate the "unrepeatable run-out" characteristics considering surface roughness of the rotor. It is found that the surface waviness components with wave length longer than the periphery length of the supply holes correspond well with irregular load capacity fluctuation (vibration excitation force to the rotor).
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