Design of Planetary Gear Reducer with Double Circular-Arc Helical Gear

Abstract

The two gears of the double circular-arc helical gear is a mesh of a concave/convex combination. Because the curvature is close to each other, the strength also increased and thus, it is often used in heavily-loaded workplaces. The national standard for double circular-arc helical gear (ex., GB12759-91) is based on the size of the gear module to design its tooth profile. This shows that tooth geometric-related designs are quite complicated. If the effect of the different pressure angle parameter is considered, we would be unable to conduct relevant studies for the original standard formula with a double circular-arc helical gear set at a pressure angle of 24°. Firstly, this paper would redefine a new double circular-arc helical gear according to the discontinuousness tooth profile molded line of the double circular-arc helical gear and unchangeable pressure angle and explain the improvements in the design and stress analysis of the tooth especially since the double circular-arc helical gear has no limitation in the minimum number of teeth. Thus, the decrease in the driving gears’ number of module and can further increase the reduction gear ratio. For heavily-loaded planetary gear reducer, it’s quite obvious in the miniaturizing and high torque superiority. This paper also used certain winch’s speed reducer as example to explain that the change of the pressure angle can reduce contact stress by 3%~40% and also enhances the torque ability by 3%~40%.