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).
The investigation and modification of a noisy 20/25HP Hypoid Axle.
| Identifier | ExFiles\Box 136\5\ scan0278 | |
| Date | 14th May 1931 | |
| To Wor.{Arthur Wormald - General Works Manager} from RHC.{R. H. Coverley - Production Engineer} c. Hs.{Lord Ernest Hives - Chair} Re: 20/25HP. Hypoid Axle to N.S's 2886 & 2917. The first Hypoid Axle was fitted to 18-G-IV, for the 10,000 miles in France and was rejected by GWH{George W. Hancock - Head Chateauroux}, after 5,000 miles running. Axle was returned to Derby for examination on the grounds that it had developed noisy. Replace axle was despatched to France, and reported upon at the completion of test as having developed noisy. Examination revealed that thrust race balls were running off their normal track, and that the thrust housing was distorted so that when the third axle was prepared for further tests in France, careful records were taken of the thrust housing and races. When the next series of tests commenced, the axle was reported noisy after approximately 2,000 miles but continued the test. When the car returned, and on examination of the axle it was discovered that the alignment of pinion had become affected due to the distortion which had taken place in the thrust housing. This had affected the bedding of the gear and also caused extremely noisy thrust bearing. Further investigation revealed that the thrust housing distortion could be reproduced on the bench by the tightening of ball race retaining nut, which distorted the housing to the extent of .006" to .010", which affected the holding down flange. This housing has an annular groove at the bottom of the thread to facilitate screwing and slotting. Groove reduced the sectional thickness causing housing to be flexible, and be owing to the fact of the outer diameter at this point, being unsupported in axle casing, the alignment became affected under load. When Da.{Bernard Day - Chassis Design}, was at Derby, his attention was drawn to the axle whilst dismantled, and the trouble explained. He promised to issue a modification to the existing scheme. Meanwhile we have produced a housing on which the undercut has been eliminated and both diameters of housing have been spigoted in axle casing. Since this modification, axle has run a considerable mileage, and so far, reports of running and examination of the housing are satisfactory. The thrust bearing as fitted is retained in it's housing by screwed retaining nut in accordance with Arrgt. Drg. G.53290, and differs from N.Schemes 2886 and 2917 which are similar to present Phantom practice. From a production point of view, retaining nut is to be preferred, as with the present scheme of retaining plate for thrust bearing on Phantom axles, difficulty is experienced in correctly adjusting this plate to ensure that same nips the thrust bearing and casing face simultaneously, so that ball race is definitely located and free from float. RHC.{R. H. Coverley - Production Engineer} | ||