| dc.description.abstract | When designing a gearbox, engineers usually need not only to confirm the load capacity, but also to consider space, weight, cost and other constraints, which usually cannot be solved quickly due to the various complex calculations involved. Nowadays, because the computation technology been greatly improved, the time cost in design development can be reduced, if the program is used to execute the complicated calculations with the given design parameters and requirements.
This paper is based on the study case of the switching stage of a two-speed gear reducer of Sendzimir rolling mill. Two speed ratios are formed due to gear shifting mechanism direct drive with ratio as one and speed reduction. There are two gear pairs with the same center distance but different speed ratios. In this study, script programs are developed by using software KISSsoft for gear calculation to speed up the analysis of this study case.
In the analysis, KISSsys, a module integration software of KISSsoft for gear transmission system, is used to establish the model of the two gears pairs of this study case. A script program is developed to find the maximal combination of gearing parameters for the torque to weight ratio and the minimum face load factor KHβ. In the study, a mathematical model is created according to the boundary conditions of the gear pairs base on the available modules in KISSsys. With aid of the developed KISSsys script program, the gearing parameters in the given range are repeatedly calculated using the KISSsoft helical gear pair module. The combination of parameters for the best torque to weight ratio is selected from the calculated results.
Then, in order to analyze and calculate the contact characteristics of the gear pairs under various conditions, the gearbox housing, the shafts, and the bearings are added to the KISSsys gear pairs model with the selected gearing parameters. Firstly, a script is used to calculate the optimal modification amount of the helix angle modification of the gear flank to solve the time consuming problem of manually repeated trial and error process. At the same time, the effect of modification on tooth contact characteristics is also investigated. Finally, the housing stiffness form FEM is also imported into KISSsys to investigate the influence of housing deformation on the tooth contact and modification amount of gears. The analysis results of the analysis show that the deformation of the shaft, bearing and housing has a significant effect on the tooth contact, and the locking bolts of the housing also changes the tooth contact characteristics. The face load factor KHβ can be reduced from 1.1~1.3 to 1.02~1.04 by applying flank modification.
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