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).
Crankpin lubrication methods for car and aero engines.
| Identifier | ExFiles\Box 138\1\ scan0086 | |
| Date | 15th January 1934 | |
| X 634 To Hs.{Lord Ernest Hives - Chair} from E.{Mr Elliott - Chief Engineer} E.2/HP.15.1.34. c. Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} Sft.{Mr Swift} Mx.{John H Maddocks - Chief Proving Officer} Rg{Mr Rowledge}/Rbr.{Mr Rubbra} Crankpin Lubrication - Car and Aero Engines. This is to confirm that on the next T.D. aero engine test you will have the crankpin lubrication holes drilled right through the pin so that there will be two holes spaced at 180°. From an examination of the failed shaft the seized portion of the pin extends from A to B on the inertia loaded side of the pin. It is R.R. practice hitherto to have one oil hole only on the leading face of pin at C. in fig.I. so that oil is supplied in front of the pressure loaded surface. This has served us very well in the past but with the increase of engine speeds which has gradually taken place all round the inertia loadings have risen considerably and form the major cause of crankpin wear which is borne out by an examination of endurance tested shafts. Under these conditions the present oil hole certainly appears to deliver the lubricant at the wrong spot, and with the clearance being on the outside of the pin there is considerable possibility of much oil being lost before it is brought in use, as shewn in fig.II especially in a test such as the aero T.D. With two holes diametrically opposite both needs of pressure and inertia loadings are catered for and we first propose to try this scheme as in fig.III, but we ought to go still further in our experiments and try closing the hole serving the pressure side, with a view to reducing the loss of oil centrifugally, [Diagram 1 Text] PRESSURE LOADING CRANK ROTATION OIL INERTIA LOADING FIG.I. [Diagram 2 Text] CLEARANCE OIL INERTIA LOADING PRESSURE FIG II [Diagram 3 Text] PRESSURE INERTIA FIGIII | ||