Research and manufacture of external non-circular gear-pair with improved cycloid profile of the ellipse

Abstract

Non-circular gears (NCGs) are known as an alternative to conventional mechanical mechanisms in continuous speed converters. In which, the gear profile is the factor that directly affects the performance and quality meshing of the non-circular gear. However, the types of curves that are being used to generating profiles of the non-circular gears still exist limited in meeting the conditions of undercutting and uniformity of tooth sizes at different positions on the centrode. To optimize the profile of the non-circular gear, the paper presents a new profile in which the traditional involute profile of the non-circular gears is replaced by an improved cycloid curve of the ellipse. The mathematical model of new profile of non-circular gear is formed by eccentric circular shaper cutter with the improved cycloid of the ellipse in accordance with the theory of gearing in consideration of undercutting conditions. Based on the mathematical model established by this research, a program was written in Matlab. On that basis, a pair of non-circular gear was designed and fabricated experimentally on a wire breaker to verify the theory. The results show that with the new tooth profile design scheme, the shortcomings of uneven teeth on the non-circular gear of the traditional studies when using the involute profile of the circle have been overcome.