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).
A.C. Alloy Bearings, detailing the properties required for improved engine performance.
| Identifier | ExFiles\Box 115\5\ scan0212 | |
| Date | 6th December 1938 guessed | |
| A.C.ALLOY BEARINGS. --------- Mr Walden to & read Greater engine speeds and higher pressures and temperatures have forced the engine builder to look for an improved material to carry the increased loads. New light alloys have been developed for parts such as pistons, crank-cases etc., new cast iron alloys for cylinders and piston rings and new steel alloys for connecting rods, crank-shaft etc. Only one part of the engine has remained much the same since the early days of the steam-engine, - we refer to bearings which have been of Phosphor Bronze or White Metal etc. . Reviewing briefly the properties required of a bearing, we find that:- 1. FATIGUE STRENGTH. Usually this is the most important pro-perty of a bearing material as it determines the allowable load and the life in the majority of cases. 2. MECHANICAL COMPRESSIVE STRENGTH. By this is meant the resistance to continued extrusion by compression at the operating temperature. It is rare that failure occurs from this source because most alloys have hardening elements which raise the mechanical strength above fatigue limit. When it does fail there will be a lip of bearing material extruded into the chamfer space or mud groove. The "conformability" of a material is a measure of its readiness to adjust its dimensions to such influences as shaft deflection and malalignment. It is perhaps a | ||