The effects of journal lobing on the performance of a hydrodynamic plain journal bearing

Accurately ground journals nominally of 44.25 mm diameter and 63.5 mm wide were produced. One was cylindrical and the others had three, four, five, six, nine or twelve equispaced lobes, 0.025 mm high, on their peripheries. Each journal was fitted into a cylindrical lead-bronze bearing liner with a radial working clearance of 0.05 mm and operated at speeds of up to 1000 rev min^?1 and at bearing loads of up to 10 kN whilst the oil pressure was maintained at or just above atmospheric pressure.The test results indicated that when a comparison is made between the lobed journals and the cylindrical journal (1) there are no significant differences in the load-carrying capacity of the bearing and (2) in the higher portion of the loading range the boundary lubrication conditions are improved when using three- or four-lobed journals whilst the presence of lobes on the other journals produces only a slightly adverse effect,It was concluded that the effect of lobing, which often occurs accidentally during the manufacture of plain cylindrical journals, is not detrimental to the performance of the bearing when operated within the range of speeds and loads used.