Abstract
M.Ing.
The study was initiated by the inquiry from an oil company to scientifically determine
the wear rate of the draglines gears. The main aim of the study was to establish an
applicable practical means of measuring the amount of wear on gear tooth surfaces and
to eventually integrate this metrology approach with finite element methodology for use
in a maintenance strategy. Various methods found in the literature were reviewed. Due to the fact that the gears would only be available for periods when the draglines are serviced, the mould between two of the gear teeth seemed to be an appropriate suggestion. The mould would form the inverse of the gear tooth profile and be used for experimental tests. As certain detail was seen as confidential regarding the draglines, the study had to be done on a more available gear. A manageable size gear was donated for research by Reumech-Gear Ratio. The gear tooth profile as well as the mould were measured using a height gauge, and a gear-tooth calliper. The profile was also scanned by means of a digital scanner with a stylus gradually moving over the gear, and shown on a computer screen. The theoretical involute gear profile was generated and used as a reference to which the measured results could be compared by superimposing the profiles onto the reference gear profile. By comparing the measured results with the theoretical profile, it could be seen that both manual and automated results were within acceptable tolerance. Accuracy versus cost by comparison, therefore, would be the deciding factor. Further, the contact between two mating gear teeth was simulated using the finite element method. Gap elements were used to connect the nodes moving to one another. The finite element methodology could be used as a helpful maintenance instrument to link the measured gear wear to the equivalent stress levels during the different operational phases of the gear system. This could be a valuable means to manage gear life.