ESR Technology’s client identified an opportunity to reduce the cost of maintenance for its vehicles by eliminating a mid-life overhaul of the gearbox. ESR Technology was commissioned to demonstrate that the change could be implemented without increased risk to gearbox life or reliability. The gearbox overhaul periodicity was based on the design duty cycle and life expectancy of the bearings. The objective was to use actual operational duty cycle data to show that the mid-life bearing replacement was not necessary.
ESR Technology developed a strategy for the existing design that demonstrated the comparable risks between the design duty cycle and the maintenance against the actual duty cycle and revised maintenance. ESR Technology analysed the operation duty cycle for the gearbox and reassessed the design life of the bearings based on the latest bearing life methodology together with in service measurement of the debris level in the oil. This identified opportunities for extending the period of gearbox maintenance. The actual operational duty cycle was then applied to the design and revised maintenance periodicities calculated.
This work demonstrated that the input bearing life set the mid-life replacement for the design duty cycle but this could be increased significantly above the gearbox overhaul for the actual operational duty cycle. The risk of spinning was analysed and shown to be the controlling factor in setting periodicity. Consequently, a design change was recommended before implementation of extended overhaul periodicities.
Risks of services failures were identified enabling proactive mitigation to take place. When implemented, the client was able to remove a complete overhaul regime for the gearbox from the maintenance plan, helping to generate significant savings.