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 considerations and alternatives for a reverse gear mechanism in a gearbox, comparing Maybach and Silver Ghost types.
| Identifier | ExFiles\Box 6\2\ 02-page139 | |
| Date | 23th January 1931 | |
| XS23 DA{Bernard Day - Chassis Design}/HDY.{William Hardy} E.{Mr Elliott - Chief Engineer}) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} BY.{R.W. Bailey - Chief Engineer} ) (At Le CanadelHenry Royce's French residence.) R1/M23.1.31. C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} HY.{Tom Haldenby - Plant Engineer} RHC.{R. H. Coverley - Production Engineer} JAPAN 3. GEARBOX. X.5310 X.523. After looking over the preliminary drawings for the above I wired that I thought we might find simpler reverse and that the jaws ought to be of the Maybach type. DA{Bernard Day - Chassis Design}/HDY.{William Hardy} has done well in watching - as we had done in P. 2. and other recent work - that splines and other parts were exactly duplicated whenever possible, and had given a fairly good alternative for the reverse pinion which had given me such a bad opinion of the otherwise good work. In addition to the 2 schemes of reverse there are 2 others that might be considered. The very simplest as far as gears go would be to revert to the Silver Ghost type of reverse pinion i.e. a simple broad pinion carried on an eccentric shaft, but I think this is generally found to be the more difficult to engage and requires a mechanism to work it, so it does not perhaps pay. The second is the best I can suggest and is very like the present and P. 2. but takes its drive from 2nd. layshaft pinion (as in your alternative) but like P. 2. the final drive is on the 1st. speed gear wheel - i.e. the great wheel of the box. The gear has to slide double distance (as in your alternative) but I think we can manage this without making the lever move more than say 1/2 times the other gears by multiplying up by lever or second slider. When the reverse is out the wheel to be driven by the 2nd. pinion is hidden away in the diaphragm in the same plane as the centre bearings. This reverse double pinion of 2 dias. is made from one piece of bar and has a floating bush at each end and slides on a plain hardened centreless ground bar of steel which may be bored up for oil, and as the drive at the larger end is double width of gear from its support it might pass 3 or 4 dias. into a supporting boss which can be cut away if it fouls the 3 speed gear. This scheme does not lengthen the box and it takes advantage of the rounded teeth of 2 gears already there and rounded for other purposes. It seems easy to put together. I think we must keep the intermediate (middle) bearings because the nose bearings on the third shaft has an easier time and the box is more silent because of these bearings, but any convenient bearings not needing to take thrust can be roller instead of ball, and thus be smaller or better for load. The front compartment will probably need to be lengthened to make a good job of the Maybach jaws from which we are hoping for great help. Have we seen any way of getting in some elasticity torsional between clutch and box - in the clutch I hope. After writing the foregoing my latest opinion is that we may find the best solution in the eccentrically carried reverse pinion; next post I will send another memo. R.{Sir Henry Royce} | ||