A Design Method for Logarithmic Spiral Movable Tooth Drive to Avoid Curvature Interference

Abstract Logarithmic Spiral Movable Tooth Drive (LSMTD) is a novel type of precision heavy-duty transmission that possesses a wide array of potential applications in the field of robotic joints. Due to the unique transmission principle, the influence of design parameters on tooth profile curvature is significant. Inappropriate design parameters can lead to curvature interference, resulting in tooth profile top cutting and subsequent transmission failure. However, the lack of research on the curvature interference characteristics of LSMTD seriously restricts the development of forward design methods. To solve this problem, this study proposes a design method to avoid curvature interference. First, a curvature interference analysis model for LSMTD is established based on coordinate transformation and the meshing principle. This model is used to analyze the relationship between top cutting and curvature interference. On this basis, the influence of design parameters on tooth profile curvature is quantitatively analyzed through orthogonal experiments. A curvature interference boundary equation is established. With the validity of the equation verified, the distribution of curvature interference boundary lines is analyzed. Finally, the effectiveness of the proposed design method is validated through a design example, and a robotic joint component is manufactured. This study holds significant implications for the forward design of LSMTD.