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).
Letter to a bearing company about the failure of a chromium iron cage in a Bentley rear axle thrust bearing.
| Identifier | ExFiles\Box 114\2\ scan0173 | |
| Date | 29th July 1935 | |
| [Handwritten: X1020] c. Hs{Lord Ernest Hives - Chair}/Grys. 29th. July 1935. BY.18/G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Messrs. Ransome & Marles Bearing Co. Ltd., Newark-on-Trent. Dear Sirs, I am returning herewith a thrust bearing from a Bentley rear axle, the bearing in question being one of the latest type i.e. it is fitted with chromium iron cage, which has failed as you will notice by breaking in three pieces. The complete mileage of the car with the bearing in question is in the neighbourhood of 2000/3000 miles only, and we are therefore very perturbed as to what is the cause of the failure. We have, of course, done a 10,000 miles run without failure with this type of cage, and we are therefore quite at a loss to explain why this one should fail in something less than 3000 miles, and it is in this direction we would like to have your help as we were definitely under the impression that by adopting the chromium iron cage we were finally clearing up the question of broken cages. This, however, does not now appear to be the case. It is just possible that the highest stress is that caused by the centrifugal force, but rapid failure of this cage as compared with our previous experience rather puts this out of court. Furthermore, the fact that the cage broke in three parts rather indicates a tendency to seize on the inner spigot with the result that the balls bring a tensile load on the small section of the cage to drag it round against the seizing effect, and the combined stress caused failure. We would like to put forward the suggestion that there might be an improvement in spigotting the cage on its outer diameter where there is a better supply of oil and somewhat reduced centrifugal loadings. Yours faithfully, FOR ROLLS-ROYCE LIMITED. [Handwritten initials: BY] | ||