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).
List of points detailing advances in the development of worm axles following a visit from representatives of David Brown & Sons.
| Identifier | ExFiles\Box 114\1\ scan0107 | |
| Date | 29th January 1937 | |
| E.1/HP.29.1.37. Visit of Mr H.E.Merritt and Mr H.L.Ritson, from David Brown & Sons, on Worm Axles. List of points on which advances have been made in developing this type of axle. (1) Large oil sump with air cooling ribs, oil being one third of the way up radius of worm wheel on under type, and half way up radius of worm wheel on over type. (2) More rigid construction of casing and gears. Ribbed differential casings used. (3) Teeth of worm wheel cut to anticipate load displacement from deflection. Entering edge of driving side of teeth on worm wheel relieved 5 thousandths, and entering edge of faces on overdrive side also relieved 3 thousandths. Correction found experimentally by running axle and observing markings. (4) Worms made from 3 1/2% Case Hardening Nickel Steel and ground after hardening, with a deep case hardened surface. The final finish is a very high polish obtained with wooden lap and finishing with felt. (5) Worm wheel in centrifuged Phosphor Bronze, same alloy as used for many years. Centrifuging increases density of metal and eliminates scrap. (6) Worm mounted on two roller bearings and located endways by floating deep groove Schatz type journal with inner race split and solid outer race. (7) Worm wheel carried on to substantial radial type bearings. (8) Axle casing formed with horizontal split, the two halves being dowelled together and each half being carried by substantial spigot in banjo when this type of casing used. | ||