The demands for safe, reliable, lighter, energy efficient and competitively priced products put a new emphasis on predictability of rolling bearing performance. This has prompted designers and engineers to estimate bearing life and optimize the design by taking into account different market requirement. Estimation of actual dynamic bearing load and life for specified class of vehicle depends upon various factors such as usage pattern, vehicle Gross Vehicel Weight (GVW), type of roads, speed, driving pattern, geographical area, ambient temperature, acceleration etc.
For estimation and prediction of life of the particular wheel bearing type it is required to identify and measure customer usage loads for different targeted markets. The measurement maps all the affecting parameters to arrive at a generalized duty cycle for bearings. A software tool is developed to predict the bearing life with these measured inputs and this enables designers to optimize bearing designs for target markets.
To work on this concept a joint project was initiated to map the wheel bearing duty cycle of a light truck for a targeted market in Europe and China region. For this purpose a panel van type vehicle was instrumented to understand bearing load distribution in terms of Center of Gravity (CG) accelerations, axle, sprung mass acceleration, bearing temperatures etc. The data measurement activity for about 3000 km for each region was carried out with different drivers, payloads and road conditions which are typical for respective markets. Extensive data analysis work was carried out in order to arrive at generalized duty cycles, market comparison and to understand parameters affecting bearing life.
This paper discusses about the methodology adopted for a duty cycle measurement, derivation/estimation of a generalized duty cycle and data analysis work performed to quantify parameters influencing bearing life.