Quantifying the surface damage of involute gear flanks independent of the gear datum axis

Abstract

Abstract Surface damage on involute gear tooth flanks can develop during the operation of a gearbox and affects their life, durability and efficiency. Understanding the extent and severity of this damage is critical, especially in long life applications such as wind turbines where gearboxes are a critical component that incur high down time and costs for replacement. Accessing gears in service is difficult and relating gear form measurements to the gear datum is often impossible without its removal. Additionally, damage measurements are typically not areal, which can miss the most severe areas, or require lengthy measurement times. This paper describes a method for characterising and quantifying localised damage relative to the undamaged tooth surface independent of the gear datum axis, and provides a method to estimate the damage location using involute co-ordinates. By taking soft replicas of the gear flank and measuring them with optical methods, the damage is characterised. This method allows for the areal evaluation of damage that relates to involute coordinates, which can be combined with nominal data or measurements after manufacture to create data sets for simulation in tooth contact analysis models, used to train condition monitoring models or for improved maintenance programming to improve reliability and reduce costly downtime.