On the Influence of the Surface Geometry of Thrust Main Bearings for Internal Combustion Engines 942396

Internal combustion engines normally use a pair of flanged bearing whose purpose is to carry axial loads resulting from the clutch system action and/or crankshaft impacts which unavoidably occur under real running conditions.
There are alternative solutions to flanged bearings like, for example, thrust washers positioned directly onto the engine block but structurally decoupled from the respective main bearing. An engine designer's choice on the subject depends, in many cases, of his knowledge of similar engines with a reliable track record or of his personal preference for a specific solution that he is fond of
However, the trend towards smaller and compact power units, i.e. of high power density (kW/L kW/cm2) has, as a result raised the mechanical loading imposed upon thrust bearings, in a number of cases, the thrust loads foreseen at the conception of the original design were exceeded by far. This factor alone results in excessive wear of the thrust faces. If, in addition, unfavorable environmental conditions prevail, the power unit useful life can be shortened drastically. The extension of the production life and/or the application versatility of such an engine hinges on the possibility of accomodating the higher loading levels predicted to occur within the dimensional constraints posed by the engine block.
It is possible to minimize the wear rate of the thrust faces through the optimization of the surface geometry. This approach is explored herein. It has been verified that thrust bearings with radially tapered faces and tapered grooves results in better overall performance.


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