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).
Potential causes and experimental solutions for knocking gears in an engine's camshaft drive.
| Identifier | ExFiles\Box 183\M22\ img197 | |
| Date | 15th September 1922 | |
| ARRIVING AT POSSIBLE CAUSES OF CAMSHAFT DRIVE KNOCKING GEARS TO H.B. & E.W. from R.{Sir Henry Royce} c. to E.W. E.W. E.P.C. [STAMP: RECEIVED SEP 6 1922] X3845 X3473 In consequence of our anxiety to settle the camshaft drive of an engine we have in hand, I shall be glad if you will let us know at the earliest possible moment whether trouble with knocking gears is due to the irregularity caused by the camshaft, or the irregularity of turning caused by the impulses on the crankshaft. It will be remembered that I suggested that if you experimentally took the whole of the slack out of the first drive to the camshaft, then the camshaft would be forced to follow the crankshaft, especially if the friction dampers are made abnormally effective. If then the crankshaft is revolving at light loads sufficiently evenly, the secondary drives both to the dynamo and to the pump - this latter will be the more critical - ought to be silent even with considerable amount of back lash. Secondly, if the crankshaft is turning evenly enough (which we doubt) then by putting sufficient load on the pump shaft drive we ought to be able to keep the camshaft in contact with the crankshaft wheel even if this is slack. If we could do this and the crankshaft revolved with sufficient uniformity then the whole of the gears including the dynamo could have back lash without knocking. Thirdly, there are naturally 2 ways in which friction on any shaft can act. One is to cause a load to keep the gears in contact, and prevent over-running. (1) | ||