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).
With suggestions for the improvement of the Japan 3 gearbox design.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan282 | |
| Date | 3rd February 1931 | |
| DA{Bernard Day - Chassis Design}/EDX. FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} C. to E.{Mr Elliott - Chief Engineer} RHG. HY.{Tom Haldenby - Plant Engineer} ORIGINAL JAPAN 3. GEARBOX. R1/M3.2.31. X5310 I am very pleased with this, but I think it can be made a little better by the following suggestions: (1) The 2 helical gears on the layshaft should be held together by the shaft. An easy way to do this without costing room would be to make the splines for the sliding pinions larger in dia. than those for the 3 fixed wheels, and as they must all be broached with the same tools we should use the ball bearing as a collar to prevent the wheels sliding along the shaft. The lip for the ball bearing would be deleted and hence slightly simpler boring (main object is self contained end thrust.) (2) I should prefer the wheel driving the reverse to have its boss level with the rim. (3) The wheel on the reverse shaft might be exactly the same wheel as on the layshaft except tooth rounding, and if we abandoned my suggested cone and put it on splines we could avoid some fitters work. The nut holding it on could be smaller in dia. and secured by split pin. Assuming that this reverse shaft is put in first it would seem that this nut and split pin could come out of the side of the box. (If it has to be made as you shew the bearing is inconveniently large in dia. because the grinding cannot run out.) (4) Assuming that the servo forward drive end pressure is taken by the large rear bearing then we might delete the lip in the bore of the box since the helical wheel is held on by a nut, but if it is in the opposite direction I should like to find some other way because it is desirable to do away with the centre lips for the sake of the bore and the more exacting assembly. (5) It does not seem convenient to combine in 1 piece the great wheel and servo worm. I am sure it would be more economical to cut something off the boss of each wheel to make a boss for the worm. (6) One can see that much work and trouble could be avoided if we used a thin casehardened (nitro-hardened) sleeve for the helical wheel. The one nut at the 4th. helical wheel could hold all (delete thread and nut and locking behind by ball bearing.) (7) I think we are free from wheels and clutches creeping but one cannot be certain. I am only suspicious of the direct drive clutch if the engine and gearbox are imperfectly lined, but it should slide about in the jaws of larger dia. and not slide along the smaller dia. The result might be some bearing end pressure, but I cannot see that we can do anything more at the moment. (8) Torsional flexibility is good we have long known between engine and gearbox, and when we get time we must fit a rubber block coupling between, and perhaps another behind the gearbox. The result is easier change and less vibration in the drive. I agree to your remarks not mentioned in this memo. R.{Sir Henry Royce} | ||