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).
Noise improvements and experiments for the 25 HP Synchromesh Gearbox.
| Identifier | ExFiles\Box 179\2\ img088 | |
| Date | 23th December 1931 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} c. to G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Wr. c. to E.{Mr Elliott - Chief Engineer} Ds. c. to Hy.{Tom Haldenby - Plant Engineer} HRC. Y5310. 25 HP. SYNCHROMESH GEARBOX. Noise. We have effected an improvement in the idling noise of our gearboxes in two recent experiments. We burnished a set of 14.DP (i.e. to M.scheme) gears after which the side shaft noise was as good as our production standard. The overrun noise on 3rd. gear was the best we have had. Next we fitted a set of Maag ground gears similar to the production constant mesh gears. For this experiment 3rd. gear ratio was the same as top. The idling again was very good. In both these tests the sideshaft noise was good enough for production and 3rd. gear no worse than that in our standard box. We are therefore in a position to standardise a synchro-mesh gearbox, except that it will not have a silent 3rd. Reverse Gear to R.Sch.3374/5. We have fitted this scheme to one of our gearboxes. Reverse gear shows no tendency to come out. The white-metal bearings had .0025" clearance and the back bush seized after 3 minutes full torque. We therefore tried .0035" clearance and spiral oilways. The back bush seized after 13 minutes. In both cases, on seizing, the bush came out of the pinion. We think that the oil holes in the stationary shaft should be at the bottom to give satisfactory lubrication to the bushes. Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls} | ||