A New Gerotor Design Method With Switch Angle Assignability

Abstract

Gerotor is generated by an oval shape generating curve, which is attached to a large pitch circle rolling on an inside smaller one. For gerotor design, existing methods are able to handle arc-based generating curves with switch angle assignability. However, when dealing with nonarc-based generating curves, the current methods do not provide switch angle assignability. The switch angle is an important parameter in gerotor kinematics; it determines the angular conjugating range on the generating curve and affects the rotor profile. In this paper, we developed a deviation-function-based design method. By using this method, users can design and directly assign switch angles to both arc- and nonarc-based gerotors. Analytical formulations of both generating and gerotor profiles are derived and summarized into a detailed algorithm in design steps. Some designed gerotor examples using our method are provided for design and process illustration.