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).
Design of change gears, specifically the adoption of a synchromesh system.
| Identifier | ExFiles\Box 179\1\ img014 | |
| Date | 28th October 1931 | |
| HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} DA{Bernard Day - Chassis Design}/HDY{William Hardy} } ORIGINAL RECEIVED R1/MB.10.31. Sent off 28. 10. 31. X 523 X S 310 C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} C. to Mr. CLAREMONT CHANGE GEARS. We are up against a loss of RR. dignity in adopting the synchro mesh. There is probably nothing so simple as far as it goes. We may live down the copying of American cheap cars as ours may be better made or designed. Personally I do not mind having to confess that I could not do or find anything better. We have had for 2 yrs. a very good idea in applying the synchro mesh scheme to epicyclic gears, but I could not get a design that promised to be simple enough. During the past weekend - Sat. Sun. and Mon. - it has occurred to me that we could get all we needed from 2 epicyclic units - i.e. 1. 2. 3. 4. and reverse - but I find this difficult to handle, and it does not give ideal ratios, but by adding one train we get the best and simplest epicyclic gear train that (after years of study by ourselves and others) I have seen - i.e. in my judgment. It is an accelerated train, and I think I can see through its most difficult point, which was the reverse speed. As it stands we get: 1st. .3 2nd. .5 3rd. .72 4th. 1.000 Reverse .3 These ratios are ideal. Synchro mesh exactly would be on 4th., and 1st. 2nd. and 3rd. are the same principle by the use of brakes equal to clutch brakes on each of the 3 annuli, after which they are locked while at rest. An ordinary main clutch is used, and a side lever with the ordinary gate. The behaviour should be the same as silent and synchro mesh on all speeds. It should idle silently. (1) | ||