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).
Design and specifications for hypoid gears, comparing different ratios and schemes.
| Identifier | WestWitteringFiles\P\2October1926-December1926\ Scan025 | |
| Date | 29th October 1926 | |
| TO BY [struck-through] FROM DA.{Bernard Day - Chassis Design} C. to Bdr. HS.{Lord Ernest Hives - Chair} ORIGINAL EAC.9. & 10. HYPOID GEARS. DA{Bernard Day - Chassis Design}1/M29.10.26. X2066 X7310 Herewith we send N.scheme 2291. shewing a 11/41 hypoid gear which gives almost exactly the same ratio as the present 14/52 gear. This is based on your GL.{G. Linnett}88. using 3½ D.P. If we use this D.P. for the lower gear we get a very small number of teeth in the pinion, and we think it better to use 4 D.P. for the lower gear. If however any difficulty is presented in the use of two different sized teeth for the two gear ratios we should like to have your remarks, otherwise to make the gear exactly comparable with the present gear it will be better to make that shewn on N. scheme 2291. in preference to that shewn on N. schm 2288., which is slightly higher than 14/52. It will be noticed on all these hypoid gears that we have not reduced the angle of edge at the back [struck-through] thick end of the pinion, so that at the pitch line the teeth are beyond the pitch line of the crown gear, as has been done on GL.{G. Linnett}88. The reason for this is that the teeth are naturally very much stronger than the corresponding spiral gear, and also naturally have a greater length of face. We have reduced the angle of edge at the small end in order to compensate for the teeth at this end being rather smaller. If you have any remarks to make on this point we should like to have them. DA.{Bernard Day - Chassis Design} | ||