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Loaded tooth contact analysis (LTCA) adopted to obtain the static transmission error for the gear optimization affects significantly the computation time and results. This paper is to study an efficient process of macro geometry optimization of helical gear pairs with LTCA. An analytical LTCA model was proposed and verified with the measured transmission error. To find an efficient LTCA method, the proposed model was divided into three types (based on whether the slice stiffness and extended contact were included) by adjusting the fidelity. When extended contact was included in LTCA, the increased computation time was very short, but the accuracy of the results improved significantly. Optimization processes were designed based on the analysis results, and it was most efficient when starting with the model considering only the extended contact and ending 5%−10% of the entire generation with the highest fidelity model. In the process, the computational effort was significantly reduced compared to when the optimization process was configured with only the highest fidelity model, and the level of optimization was almost equal. [ABSTRACT FROM AUTHOR]

Geometric interference can occur in cylindrical worm gear set that makes use of oversized hob to cut the worm gear. In particular, the interference occurs easily in the design with high lead and low pressure angles. The interference results in a corner contact. In this study, we examined the influence of the machine tool setting errors of the worm gear hobbing and the influence of the shaft misalignments of the worm gear set on the interference. To determine the interference, we used the surface separation topology based on differential geometry. In addition, we also examined the hob oversize range required to avoid the interference under the condition of the machine tool setting errors and shaft misalignments. This study found that the interference can be avoided not only when the hob oversize is larger than the upper limit, but also when the hob oversize is smaller than the lower limit. This study also found that the interference can be avoided by applying the intended errors on the machine tool setting and shaft alignment, without manipulating the hob oversize. [ABSTRACT FROM AUTHOR]

Geometric interference can occur in cylindrical worm gear set that makes use of oversized hob to cut the worm gear. In particular, the interference occurs easily in the design with high lead and low pressure angles. The interference results in a corner contact. In this study, we examined the influence of the machine tool setting errors of the worm gear hobbing and the influence of the shaft misalignments of the worm gear set on the interference. To determine the interference, we used the surface separation topology based on differential geometry. In addition, we also examined the hob oversize range required to avoid the interference under the condition of the machine tool setting errors and shaft misalignments. This study found that the interference can be avoided not only when the hob oversize is larger than the upper limit, but also when the hob oversize is smaller than the lower limit. This study also found that the interference can be avoided by applying the intended errors on the machine tool setting and shaft alignment, without manipulating the hob oversize. [ABSTRACT FROM AUTHOR]