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 improvements and considerations for gearbox design, including gears, cams, and synchronisation.
| Identifier | ExFiles\Box 136\4\ scan0111 | |
| Date | 1st November 1933 guessed | |
| - sheet 5 - More Solid Gears. We have noticed that the gears of American boxes are stronger than appears necessary but the reason may be more connected with distortion in hardening and the use of unground gears than with any inherent quietness. Our tendency is towards more solid gears on the SpectreCodename for Phantom III and Wraith as the loads are heavier and the gears smaller than before. Three Cams. There may be an advantage in the use of three cams as, at the moment of synchronisation, the sleeve is centralised by the cam surfaces. Our split actuating ring on the top and third speeds makes the use of three cams inconvenient here but on the second speed there is not this limitation. Actuating Forks. We might try the actuating forks bearing directly on the collars suitably cut away to minimise the effect of deflection. Oil Feed. We are considering the use of a screw thread to feed oil to the loose gears on the third motion shaft as suggested by Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} on his return from America. We have had no evidence that anything more than we do now is necessary but a scheme which adds little to the cost and weight would perhaps be worth adopting. Reverse Stop. A lateral reverse stop is being tried by the Expl. Department with a view to eliminating the loose parts on the gear lever and so overcoming the complaint about noise from the Bentley lever. So far, there has been difficulty owing to the momentum of the pieces when moving across the gate overcoming the stop when not intended. - The Alvis has a great advantage with the ball mounted lever as the inertia of the parts is much less. Jaw Clutches. No special provision appears to be made on either of the boxes to prevent the jaw clutches working out. Synchronisation of First Speed. We should naturally have included the 1st speed in the synchromesh when designing the boxes which have the 2nd speed synchronised but for the difficulties, which are:- | ||