The testing of expanding disc oil caps for crankshafts, detailing issues with leakage, vibration and extraction.
| Identifier | ExFiles\Box 123\5\ scan0131 | |
| Date | 25th October 1938 | |
| 25.10.38. EXPANDING DISC OIL CAPS. FD. {Frank Dodd - Bodies} 209 Crankshaft (EE.4104). Using dummy test pieces representing the journal and crankpin sections of this type of crankshaft, discs made in S/DS. having interferences up to .015 were first formed and then repressed flat into the models. Each assembly was then tested hydraulically up to 150 lbs/sq.in. pressure using D.T.D.109 oil at 90°C. When pressed into position the discs in all cases were waved, and concave at the centre, as usually experienced with this scheme when the disc cannot be supported internally. Irrespective of the diametral interference there was a general tendency to sweat, although there was never excessive leakage. When this type of disc was previously tested without the undercut it would stand a reasonably high internal pressure without blowing out, but fell out when subjected to vibration. Whilst the undercut eliminates any danger of discs being blown out, they will slacken off under conditions of vibration and torsion as in a crankshaft; consequently the leakage will be increased considerably. Difficulty was experienced in extracting the discs - this would be necessary when "desludging" a crankshaft - the simplest method being to first punch the discs into the bore, but this is not recommended (particularly with soft shafts) owing to possible damage to the shaft. Some difficulty will be experienced with the crankshaft proper in obtaining tackle sufficiently strong to press the discs into position owing to the confined space, a load of approximately two tons being required. HPS {Horace Percy Smith - Experimental Factory Mgr} /W. Bell. | ||
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).