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).
Gear design for back axles, focusing on over-run, and proposing experimental gear cutting methods.
| Identifier | ExFiles\Box 2\6\ B002_X 140 141 157-page017 | |
| Date | 21th May 1923 | |
| (3) back axle and torque tube for the weight this chassis is intended to carry. (It should be examined for this and particulars taken as above). I have always had the impression that a good gear, bevel or spur, or even worm or chain drive, is one that drives as the teeth recede and not on approach, and have often made such spur gearing knowingly which have been satisfactory. As the bevel gearing in the back axle has to over-run I never conceived it possible to apply this to the back axle gears. It has struck me, however, that it is possible because of the reason that a different side of the tooth is used for the over-run than the driving. I suggest, therefore, that some experimental gears be cut. The wheel should be cut normal but, after cutting the driving sideof the pinion normal, it should be moved in the machine towards the apex of the theoretical cone, from .005 to .010" or such amount as experiments des-cribed further show. Before cutting such gears, however, a number of axles should be tested as regards setting of the pinion to get the two best positions, i.e. 1st. best forward only, and 2nd. best retard only. | ||