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).
Preliminary report on improving the quietness of 25/30 HP engine timing gears and Phantom gearbox gears.
| Identifier | ExFiles\Box 136\5\ scan0304 | |
| Date | 3rd April 1937 | |
| To RHC.{R. H. Coverley - Production Engineer} c. to Hs.{Lord Ernest Hives - Chair} [crossed out] c. to Rm.{William Robotham - Chief Engineer} c. to Cyr. [crossed out] 1152 25/30.HP. ENGINE TIMING GEARS & PHANTOM GEAR BOX GEARS. Preliminary Report. The Test Department request that the standard of quietness of all gears shall be higher than at present. TIMING GEARS. The gears fitted consist of 4 off S/ZNCR.hardened, 1 off bronze, the teeth are not ground and have a pitch line run out of .001 to .003. The teeth are heavily lapped often hand polished, and a moderate degree of quietness is obtained by running in. Assembled gears are then run in the engine and passed off when judged to be satisfactorily quiet. Later heavy running on the unit test, dynamometer, and road, can each have an influence on these gears, and a final judgment of quietness on the road is necessary. Under existing conditions some improvement may be made by greater attention to detail, but gears distorted in hardening are extremely difficult to improve. The distortion is never completely removed by lapping. To effect any marked improvement in quietness the accuracy of the gears must be greatly increased, as by grinding of the teeth, or gears heat-treated only, and not hardened, or a change in the Design. Detailed measurements are being taken for guidance in making improvements. Some degree of measurement is aimed at, to supplement the present noise test at this stage of erection, prior to unit test. PHANTOM GEAR BOXES. These gears are hardened and the teeth ground. Investigation has been centred on the constant mesh gears, these being mostly in complaint. Examination of these gears shows that the accuracy of the teeth is influenced by the uneven amount of stock which is found on sides and bottom. The gear grinding wheels tend to follow the amount of stock which has to be removed. Readings taken of the involute profile of each successive tooth of a gear, and spacing from one tooth to another, show variations | ||