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 tooth precision and constant velocity as a means to eliminate noise.
| Identifier | ExFiles\Box 75\1\ scan0045 | |
| Date | 5th February 1913 guessed | |
| -2- utmost precision in each tooth, or in other words, that the curves of each tooth, although exactly similar for every tooth, were not such as would give a constant pitch line velocity or a constant angular velocity for the driven wheel if the driver was running at a constant speed. The point which came to me with some force was that there could be no noise or note of any power or consequence providing that the pitch line velocity of one wheel is always exactly the same as the pitch line velocity of the other wheel. Anything which would tend to disturb these relative velocities would necessarily be in the form of a blow between the teeth, but given no variation in the velocities it is almost impossible to imagine any noise or note ( I am neglecting such points as the rubbing of two smooth surfaces which could not cause any appreciable noise providing those surfaces were lubricated). I think this point of constant velocity is of the utmost importance, and although no doubt it is fully appreciated by anybody who has anything to do with gears, yet I think there are certain ways of utilising this point, which have not been fully gone into. This point of constant velocities of the two wheels suggested to me the following idea :- If heavy flywheels were bolted rigidly to each wheel and those wheels had teeth of such perfect formation | ||