BEARING TYPE – CRITERIA, APPLICATIONS AND TECHNICAL RECOMMENDATIONS

The choice of the suitable bearing type is a significant step in the mechanical design, which has a direct impact on the system performance, reliability, and efficiency. Bearings are devices that are used to enable rotational or linear movement, while reducing friction and handling stress. Selecting the right bearing entails a multi-objective decision process which considers factors such as the application requirements (e.g. the type and magnitude of the load, the speed, misalignments, the temperature, the lubrication, the environment, spatial constraints). For example, deep-groove ball bearings are widely used in electric motors and other household appliances, they are capable of carrying moderate radial and axial loads simultaneously at high speeds; while tapered roller bearings, used for vehicles' wheel hubs, are capable of carrying combined loads and large loads in one direction. In high-speed spindles or precision instruments angular contact ball bearings are best when greater high-speed capability is required and in also handling axial loads and being able to be positioned and accurate enough for precision mounting, especially in the tightness of the corner that the bearings are being used. However, spherical roller bearings are ideal if the machine component being supported also experiences misalignment and is subjected to shock loads. Various other environmental conditions including dust, moisture, and corrosive substances may require sealed or shielded bearings or alternative materials (e.g., ceramics, polymers). Additionally, maintenance access, expected working life also is an important factor to consider whether a bearing requiring lubrication, is sealed for life or can take tough working cycles. Hence, the selection of a bearing cannot be made simply on the basis of the theoretic or empiric evidence, but requires a comprehensive knowledge of mechanical and tribological fundamentals, combined with experience and taking into account industry standards and the recommendations of the bearing manufacturers. This procedure leads to increased useful life of the devices, reduction in downtimes, and to improved effectiveness of the systems in a vast spectrum of engineering applications.