John Crane provides engineered solutions that are individually tailored to each application and characterized through their operational features. Of all hydrodynamic bearing types, tilting pad journal bearings offer the optimum in rotor stability due to their exceptional stiffness and damping characteristics. The reduction in cross-coupling coefficients provides the basis for maximum rotor stability in high-speed applications. For this reason, tilting pad journal bearings are ideal for use in high-speed machinery operating under low to medium loads.
Creation of a convergent wedge profile is achieved through the pad geometry, clearance and movement capability of tilting pad bearings. When the shaft begins rotating, the lubricant’s adhesive effect on the shaft acts to pull the lubricant into the gap, which narrows in the direction of rotation. Pressure develops in the fluid film to create a running clearance between the stationary and rotating surfaces. John Crane tilting pad bearings consist of a steel housing and either four or five journal pads, which are supported/pivoted centrally to enable shaft rotation in either direction. The bearing pads are normally manufactured with a low to medium carbon steel backing and a high-quality white metal (Babbitt) lining. The white metal lining, a predominately tin-based material, provides critical functionality to help reduce shaft damage during any transient, upset, slow speed or contamination condition.
Temperature monitoring through the use of RTDs or thermocouples is a prerequisite to ensuring reliable machine operation. In addition, several design options are available to optimize bearing performance, including offset pivot configuration, material selection and lubrication scheme design. Flooded bearings incorporate a partially or fully flooded bearing cavity and are laterally sealed using floating rings. In directed lubrication designs, the oil flow to the bearing is metered through inlet nozzles to break up the hot oil film on the shaft and reduce bearing temperatures. The use of our patented Advantage® system provides additional functionality by helping reduce hot oil carryover through the employment of a helix V-wiper on the leading edge of each journal pad. Directed lubrication bearings provide the additional benefit of lower energy consumption. Whatever the application, John Crane has an engineered solution to meet your needs.