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 solutions for the top gear working out on a 25 HP Synchro Mesh Gearbox.
| Identifier | ExFiles\Box 179\1\ img177 | |
| Date | 19th December 1931 | |
| HS.{Lord Ernest Hives - Chair} AHD. FROM DA{Bernard Day - Chassis Design}/HDY.{William Hardy} GRY{Shadwell Grylls} RECEIVED DA{Bernard Day - Chassis Design}/HDY{William Hardy}1/M19.12.31. C. to - SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to - E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} 25H.P. "SYNCHRO MESH GEARBOX. TOP GEAR WORKING OUT. X5310 (1) If this is due to mal-alignment of the 1st. and 3rd. motion shafts it appears to us that it is the resulting lack of concentricity of the driving and driven teeth that matters. It may be possible to prove this by the removal of the spigot bearing on a car that is giving trouble. The flexibility of the 3rd. motion shaft should then enable the teeth on the sliding member to centralise themselves. It should be noted that there is no apparent reason why the synchro mesh box should be worse than the standard box. A spigot bearing in the plane of the teeth may be a cure but is not easily done except as a plain bearing, and lubrication is difficult. The placing of the splines at the rear of the sliding piece as suggested later avoids "out of concentricity", and is we think worth a trial. We should like to know whether a gear that works out on the over-run works in on the drive. (2) The proportions of the sliding piece on the 3rd. motion shaft are very different from those of the standard box, and it occurs to us that there may be some advantage in placing the splines at the rear of the sliding piece. We are accordingly sending two suggestions for trial in case the trouble remains without a satisfactory solution. DA{Bernard Day - Chassis Design}/HDY.{William Hardy} | ||