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).
Bentley Rear Axle Pinion Thrust Race failures and subsequent bearing tests.
| Identifier | ExFiles\Box 114\2\ scan0010 | |
| Date | 1st February 1934 | |
| To Sg.{Arthur F. Sidgreaves - MD} from Ha/Gry.{Shadwell Grylls} c. to Wor.{Arthur Wormald - General Works Manager} c. to Rg.{Mr Rowledge} c. to E.{Mr Elliott - Chief Engineer} c. to Da.{Bernard Day - Chassis Design} c. to Hdy.{William Hardy} X3807 Ha/Gry.{Shadwell Grylls}9/KW.1.2.34. see also File 4553a (10000 mile test) Bentley Rear Axle Pinion Thrust Race. We have now had a total of 5 failures of this thrust race. We visited Ransome & Marles to ask their advice as to the cause of the failures and how to prevent them. They were positive that the failures were due to overload, and pointed out that in our mounting of the bearing one half of the race only takes all the forward journal and thrust load. By relieving the outside diameter of the half of the race further from the pinion so that this thrust half could take no journal load, we should use the bearing more efficiently and nearly double its capacity. We then asked them what was the highest capacity bearing they had that would fit in the existing space. They put forward a bearing relieved as above and of altered contact angle that should make us 2.6 times as well off. They have carried out tests on their rig (drawing attached) at 3000 r.p.m. with combined journal and thrust loads of twice our top gear full torque loads. The Hoffman bearing failed in 24 hours and shows evidence that one half of the race had done all the work. The Ransome & Marles bearing relieved on one half but with normal contact angle failed in 39 hours. The increased capacity bearing has now run 50 hours and is in perfect condition, and in their opinion will certainly last a further 50 hours, which test they are continuing. It is this latter bearing that we are running 10,000 miles in England fitted to Z-3-IV. What we particularly like about this bearing is that it exactly replaces the existing bearing without in any way altering the setting of the pinion. A fitter supplied with the usual range of washers to adjust the nip on the bearing could change an old one for the new one in about 3 hours. | ||