From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Analysis of manufacturing processes for flanged bearings, comparing casting methods with folded strip production.
Identifier | ExFiles\Box 114\2\ scan0115 | |
Date | 23th February 1935 guessed | |
(3) Op. 5. Bearings are then flanged and folded in one operation. Considerable outlay in equipment would be required to produce bearings of this type, but since it is possible to produce bearings by the 'puddle-cast' or centrifugal cast process with the same weight reduction, there would be no object in manufacturing by the folding process or in obtaining similar bearings from outside suppliers. In fact it is considered that the centrifugal cast gives a more reliable material structure for Conn. Rod duty than either of the alternative processes, particularly since hardened cranks are used on chassis production on which bearings of this type are more reliable than soft crankshafts. A number of bearings which have been produced by the Allison process have been run on Experimental test engines and the pounding to which they have been subjected with increased clearances has resulted in a breakdown of the lining which is not so liable to arise with the centrifugal cast since this gives the 'onion' skin structure. It will be observed that it is impossible to produce bearings in the strip form with the Lead Bronze over the flange owing to the risk of fracturing the material and affecting adhesion, but we can produce by both the 'puddle-cast' and centrifugal cast processes bearings of this type on which the Lead Bronze will be extended round the flange. Bearings cast in this manner would be produced oversize leaving sufficient for sawing through and then collapsing to the required diameter, one casting making two complete bearings. By this means it is possible to produce thin type bearings with 1 m/m.{Mr Moon / Mr Moore} - .039 steel backing and a lead bronze lining of .015-.020 section which gives the weight reduction required. It is considered that the American practice of producing from folded strip involves considerable risk of fracturing the bronze lining and impairing adhesion, thereby causing the metal to break away from the shell after the manner of those which have been used on Bentley. continued. | ||