In an automotive transmission system, gear mesh misalignment implies the shift in the position of the meshing surfaces. Misalignment at the mesh results in non-uniform load distribution leading to gear failure, increased noise and thus affects the transmission performance. In general, misalignment along the line of action (MLOA) of 0-5 mrad is common in the gear meshes of automotive transmissions. Major factors contributing to mesh misalignment are deflections of various elastic components in the transmission like shaft, gear web, bearing, housing etc. Contribution from other factors include clearance between the components, temperature gradient and manufacturing process limitations. Different approaches for compensating gear mesh misalignment involves control over the above factors at design and manufacturing stages.
This paper focuses on three different approaches for compensating MLOA in the design stage. As today’s transmission should be lighter to have more power to weight ratio, gear web design plays a significant role in controlling deflection at the gear mesh. Various web designs are analyzed using 3D FEA tool (GSAM) which depicts the influence of different web shapes on MLOA. Influence of helix angle and pressure angle on MLOA is studied using design of experiments (DoE) approach. As the MLOA cannot be eliminated completely by design of web and macro geometry, approach of micro geometry to compensate for the remained MLOA is described.
This study provides an understanding on importance of gear web designs, gear macro geometry parameters and gear micro geometry technique to compensate for mesh misalignment in geared system.