| Summary: | 碩士 === 國立中正大學 === 機械系 === 93 === Rotating shafts are generally employed in industrial machines such as aviation generator, steam and gas turbines, turbo-generators, internal combustion engines, reciprocating and centrifugal compressors. Gear systems are one of the most common mechanisms for modern power transmission. They are often coupled with rotor-bearing systems that are the source of power generation and power extraction. On account of the increasing demand for high speed and high accuracy transportation, the research in the field of geared rotor dynamics becomes very important.
In industry, the shaft of geared rotor-bearing system would deform for a long time working. In this situation, the shaft will have residual, which changes dynamic characteristics of geared rotor-bearing system. This study discusses dynamic characteristics of gear rotor-bearing system, which under the residual shaft bow effect.
A finite element model of the geared rotor-bearing system is developed by taking account of the coupling effect of lateral-torsional motion to obtain the natural frequency and the steady-state response under the effect of residual shaft bow. The steady-state response is investigated for different residual shaft bow, different phase angels between residual shaft bow and gear eccentricity, and different disk positions. Eventually, the effect of gear mesh stiffness on system natural frequency is discussed.
As seen from results, the effect of the residual shaft bow is like the unbalance force. The effect of the disk unbalance is 0.077 times than the effect of the residual shaft bow unbalance. The direction of the residual shaft bow unbalance is changed with different phase angle. And the steady-state lateral response of the system is changed with different direction of the residual shaft bow unbalance. The location of the gear on the shaft will change the equivalent stiffness of the system. When the gear positions are closed to the bearing the equivalent stiffness of the system will increase and the system response will decrease.
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