A reliability-based approach is presented for the design of three-speed automotive transmission systems. The design of an automotive transmission system involves the design of the gear train, shafts (input, connecting, and output), bearings, keys, and splines. The gear train is idealized as a weakest-link kinematic chain, and the design is conducted with respect to failure due to bending and surface wear. The shafts are designed with respect to fatigue failure due to bending and torsion. The design of bearings (cylindrical roller bearings), keys, and splines are based on the maximum allowable stress in the components. The failure of the system is assumed to correspond to zero output power from the transmission system based on a series-parallel model. The reliability-based design is conducted for a specified value of the reliability of the system. The structural and kinematic designs of the transmission system (i.e. the gear train) are assumed to be known. The design parameters such as power transmitted, gear face widths, dimensions of roller bearing, length of splines, length of keys, and material properties are considered as random variables. The reliability-based design results are compared with those obtained by a deterministic design procedure. The effects of variation of design parameters, such as the reliability of the system and coefficient of variation of the input speed are also studied. In addition, a comparison of the designs obtained with different distributions of the random variables is also made and conclusions drawn.
ASJC Scopus subject areas
- Safety, Risk, Reliability and Quality
- Industrial and Manufacturing Engineering