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).
Technical memorandum regarding noisy Bentley rear axles due to a loss of preload on the pinion bearing.
| Identifier | ExFiles\Box 84\4\ scan0289 | |
| Date | 13th September 1937 | |
| 202 Hd.{Mr Hayward/Mr Huddy} (For Depot Sheet). c. By.{R.W. Bailey - Chief Engineer} C. Hs.{Lord Ernest Hives - Chair} C. Da.{Bernard Day - Chassis Design} c. GWH.{George W. Hancock - Head Chateauroux} See also Depot Sheet file Rm{William Robotham - Chief Engineer}/Gry{Shadwell Grylls}3/R.13.9.37. BENTLEY REAR AXLE. By confirmatory tests carried out by GWH.{George W. Hancock - Head Chateauroux} at K.{Mr Kilner}, we have shown that axles, noisy on the over-run, which in the past have been cured by fitting a new bearing, have become noisy due to loss of pre-load of the pinion bearing. The method of checking the preload is explained on the attached blue print. Both the Works and K.{Mr Kilner} have the necessary gauges. The loss of preload is due to shrinkage of the ball diameter and slight wear of the races. To regain the necessary preload requires more accurate grinding than can be done easily either here or at K.{Mr Kilner} We have made arrangements with Ransome & Marles to service slack bearings by grinding off the necessary metal and also renewing the thrust cage. If Hd.{Mr Hayward/Mr Huddy} will send R.{Sir Henry Royce} & M.{Mr Moon / Mr Moore} a batch of 20 such bearings they will very carefully examine the thrust cage which we know is liable to failure if run in a slack bearing. If none need re-newing we will discontinue changing them, but if one has cracks of incipient failure it would be wise always to change this one cage in a slack bearing. The cost of servicing a bearing will be about 3/- against £1 for a new one. It will be better than a new bearing in that the initial shrinkage of the balls has already taken place. The question of adopting more preload, i.e., about .003 is receiving urgent attention. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||