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).
Increasing gear strength by modifying circular pitch and teeth thickness, including a cross-section diagram.
| Identifier | ExFiles\Box 49\2\ Scan184 | |
| Date | 13th October 1923 | |
| - 3 - instructed experimentally, using approximately the same diameter of crown wheel which would increase the circular pitch from .7854" (4 DP) to 1.855". This will have the effect of increasing the strength of the teeth by about 10%, also if we thicken up the teeth as we do in the case of the 20 HP. chassis pinions, we shall obtain another 15%, making a total of 25%. The proposed new gears would give road speeds of 25.1 and 29.68 m.p.h. which are the speeds Mr. Royce suggested in R6/M.{Mr Moon / Mr Moore} 13. 10. 23. We feel sure that if the pitch chosen is strong enough for the work it has to do, together with the thickening up of the pinion teeth as suggested, there should be no necessity to increase the radii at the bottom of the teeth. We are putting the above facts before you so that if necessary you will be in a position to discuss the matter with R.{Sir Henry Royce} From our point of view, and hope that the information given will be useful. BY.{R.W. Bailey - Chief Engineer} | ||