Geometry generation principle and meshing properties of a new gear drive

Abstract

The generation principle of composite cycloid is proposed for the tooth profile of external drive. Firstly, a two-link mechanism is developed as the equivalent mechanism to describe the geometric principle of cycloid by introducing the motion transforming method. Then the path curve of n-order cycloid motion is generalized using n+1 link mechanism. The new second-order, third-order and fourth-order composite cycloid equations of tooth profiles, including the corresponding link mechanisms, are derived and compared. It is found that the fourth-order composite cycloid is more suitable and potential for the gear design. Secondly, based on differential geometry and meshing theory, the mathematical models, including original composite cycloid profile, meshing equation, conjugate profile and meshing line are established. Subsequently, the meshing properties, such as contact ratio, sliding ratio and mechanics property analysis are conducted and compared with involute gear drive. Transmission efficiencies under different operating conditions are performed on the FZG gear test rig. Theoretical and experimental results demonstrate that greater contact ratio, smaller sliding ratio, superior bending and contact stress, and high efficiency of the new gear are represented in comparison with the involute gear.

Keywords

• gear drive
• composite cycloid gear
• meshing characteristics
• mathematical model