| Summary: | 碩士 === 國立臺北科技大學 === 機電整合研究所 === 91 === This study uses numerical simulation methods to investigate the dynamic behavior of the first order elliptical gears under sinusoidal-wave and square-wave mesh stiffness variation. The pressure angle effect is also incorporated into the equation of motion to investigate the dynamic response along the line of action of the meshed elliptical gears. The results are compared with those of circular gears with the same center distance and the number of teeth as well as the elliptical gears without pressure angle effect. The input parameters during the
simulation include the variation of eccentricity, damping ratio, and input torque.
From the simulation results, the dynamic response due to sinusoidal-wave and square-wave mesh stiffness are similar, but the amplitude ratio under square-wave mesh stiffness is larger than that under the sinusoidal-wave mesh stiffness. With the pressure angle effect, the following can be concluded：(a)When the eccentricity is increasing at high damping ratio(ξ=0.1), the range of the main resonance region becomes wider and the amplitude ratio becomes larger in the region away from the main resonance. In addition, the circular gears and elliptical gears with eccentricity smaller than 0.3 have better dynamic response when rotating speed is less than 2500 rpm. (b)When the eccentricity is increasing at low damping ratio(ξ=0.01), the amplitude ratio at the main resonance region can be effectively reduced, but more dynamic instability areas are created at high frequency region. Examining the results of considering or not considering the pressure angle effect, the following can be concluded：(a)At high damping ratio (ξ=0.1), no matter what the magnitude of the eccentricity is, the amplitude ratio owing to the pressure angle effect is bigger except at the main resonance region. (b)At low damping ratio(ξ=0.01), elliptical gears with the eccentricity greater than 0.5 will produce more resonance areas at high frequency region if the pressure angle effect is considered during the simulation. Therefore, the elliptical gears with the consideration of pressure angle effect result in more limitations of the applied rotating speed.
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