US Patent 8104972 Bearing arrangement

A number of machines such as gas turbine engines have asymmetric axial loading along a shaft (2, 3, 4). In order to accommodate for this asymmetric loading, known as an end bearing load, a load share bearing (103) is typically provided. However, specifying the fixed bearing (11, 12) becomes increasingly difficult as space and weight considerations are taken into account. In such circumstances providing a combination of a fixed bearing (11, 12) and a load share bearing (103) to achieve an acceptable bearing end load capacity is more acceptable. The proportion of the combination provided respectively by the fixed bearing and the load share bearing can be varied dependent upon operational stage in order to achieve more efficient operation.