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).
Pinion bearing modifications, load capacities and recommendations for various car models.
| Identifier | ExFiles\Box 84\4\ scan0294 | |
| Date | 23th September 1937 | |
| 2. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}9/MH.{M. Huckerby}23.9.37. It is doubtful whether the present size of bearing will stand the necessary preload. Hdy.{William Hardy} has suggested a three row bearing consisting of a roller separating opposed preloaded angular contacts. Unless the over-run bearing is located or the preload is sufficient to prevent distortion at low torques the advantages of this scheme are prevention of distortion at high loads and probably a longer preloaded life, as the rollers instead of the balls will take the large journal loads. The figures obtained indicate that the best arrangement would be an enlarged edition of what we have now, sufficiently preloaded to prevent distortion and sufficiently large to 'stay put'. Up to now we have made only modifications that go in the existing space, so that they can be used for complaints. We now recommend that for Bentley III the centre case is modified and a larger bearing incorporated. We do not think otherwise, we shall be free from trouble. Dynamometer running on Phantom III 30-EX has shown that the pinion bearing is the most highly loaded part of the axle. It takes five pinion bearings to wear out the rest of the axle. We also attach a chart showing the relative bearing loads on P.II, P.III, and Bentley. The P.II was a model of reliability. The rated capacity of the original Bentley bearing of 1000 lbs. has now been superceded by one with larger balls of capacity, 1120 journal and 1290 thrust. R & M can supply a bearing size 30 x 83 x 1.9/16 of capacity 1400 journal and 1610 thrust. We think this should be used on B.III Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||