Dynamic behavior of an agricultural power take-off driveline for rattle noise reduction: Part 1. Effect of spline tolerance on the power take-off rattle noise

An agricultural tractor has a power take-off (PTO) driveline that is directly connected to the engine to improve its power transmission efficiency. The PTO driveline comprises various mechanical components coupled by a spline joint. The spline coupling tolerance causes collisions between various mechanical parts of the PTO driveline and affects gear collision, thereby causing rattle noise. Therefore, the aim of this study is to conduct a dynamic behavior analysis to predict the gear rattle noise level of a PTO driveline. The dynamic behavior of the PTO driveline was analyzed through 1D simulations, and the results confirmed that the dynamic behavior changes according to rotation speed. Experimental verification of the dynamic behavior analysis results confirmed that the dynamic behavior changes as the main engine excitation-component amplification changes and then decreases at a relatively high rotation speed. Additionally, the dynamic behavior changes of the PTO driveline resulted in a jumping phenomenon that occurs rapidly at a specific rotation speed. The amplification of the engine's main components was reduced from 3 to 4 times to 1.2 times owing to the jumping phenomenon; the noise level of the gear rattle was also reduced by approximately 10.9 dB(A). (C) 2021 ISTVS. Published by Elsevier Ltd. All rights reserved.N

Influence of gear tooth addendum and dedendum on the helical gear optimization considering mass, efficiency, and transmission error

In this study, the effects of the gear tooth addendum and dedendum on the optimization results for gear macro geometry design were evaluated. First, gear optimization using macro design variables was performed, excluding tooth addendum and dedendum parameters. Subsequently, the optimization, including the addendum and dedendum variables, was performed by applying the same addendum and dedendum lengths to the pinion and wheel. Finally, the gear optimization using different addendum and dedendum lengths for the pinion and wheel was completed. The gear mass, gear mesh efficiency, and transmission errors were considered as objective functions for optimization. The optimization results were min-max normalized, and the average values of the total scores were compared. The results show that the average score of the optimization considering only the main design variables was 2.7085 points and that considering the addendum and dedendum was 2.7829 and 2.8830 points, respectively, from a maximum possible score of 3.000 points. Hence, a gear macro design with better performance could be established by considering the tooth addendum and dedendum.N