The forging of helical gears (II): comparisons of the forging processes

In this study, the forging processes of helical gears have been investigated wherein they have been classified into two types: the guiding type and the clamping types. These two types of forgings of helical gears have been analyzed by using the upper-bound method. New kinematically admissible velocity fields of the clamping-type forging of helical gears have been proposed, where an involute curve has been introduced to represent the tooth profile of the gear. The proposed velocity fields of the clamping-type forging of helical gears have been applied to the non-symmetric lateral extrusion forging and the result has been compared with the solution proposed by Plancak et al. [J. Mater. Process. Technol. 1992; 34:465–472]. Numerical calculations have been carried out to investigate the effects of various parameters, such as modules, number of teeth, helix angles and friction factors on the clamping-type forging of helical gears. For the forging of helical gears, the results of the upper-bound analysis of the clamping type have been compared with those of the guiding ones. Some experiments of the clamping-type forging were carried out with commercial aluminum alloy to show the validity of the analysis. Good agreement was found between the predicted values of the forging load and the experimental forging load.