Formula derived from particle swarm optimization (PSO) for optimum design of cylindrical roller profile under EHL regime

The design of compact and inexpensive mechanical drives and gearboxes can take advantage from the use of custom rolling bearings in which the rolling elements are directly in contact with the shaft...

Optimal design of radial cylindrical roller bearings for maximum load-carrying capacity

Based on the relationships from the ISO 76 standard, this paper optimizes the internal dimensions of tapered roller bearings for maximum static load capacity. A bearing system formed by two identical bearings is assumed, subjected to whatever combination of centred radial and axial forces. It is shown that the static capacity increases linearly with the roller infill, with the ratio of roller length to roller diameter and with the square of the pitch diameter of the roller set. Further, given the ratio of axial to radial force, an optimal contact angle exists which maximizes the static capacity of the bearing pair, regardless of the actual bearing size and ratio of roller diameter to pitch diameter. The optimization procedure can either be used to design custom-made bearings or to pick from manufacturers’ catalogues the bearing with the best contact angle for any assigned loading condition.

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Optimal design of paired tapered roller bearings under centred radial and axial static loads

Ball bearings are widely used as important components in most of mechanical engineering applications. These bearings find wide applications in automotive, manufacturing and aeronautical industries. The problem associated with ball bearings is that the design and selection are based on different operating conditions to reach their excellent performance, long life and high reliability. This leads to the requirement of optimal design of ball bearings. Optimisation aspects of a ball bearing are presented in this paper considering three different objectives namely, dynamic capacity, static capacity and elastohydrodynamic minimum film thickness. The design parameters include mean diameter of rolling, ball diameter, number of balls and inner and outer race groove curvature radii. Different constants associated with the constraints are given some ranges and are included as design variables. The constraints considered are pertaining to the assembly angle, ball size, bearing width size, ensuring running mobility, thickness of bearing rings and curvature radii. The optimisation procedure is carried out using a modified particle swarm optimisation (PSO) technique. Both single and multi-objective optimisation aspects are considered. The results of the proposed technique are compared with the previously published results. The proposed technique has given much better results in comparison to the previously tried approaches.

D.P. Vakharia

Papers

Multi-objective design optimisation of ball bearings using a modified particle swarm optimisation technique