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).
Modifying oil pumps to reduce noise, discussing recesses and gear tooth obliquity.
| Identifier | ExFiles\Box 149\2\ scan0003 | |
| Date | 26th August 1919 | |
| To EH. from E.{Mr Elliott - Chief Engineer} c. to CJ. c. to BN.{W.O. Bentley / Mr Barrington} c. to BY.{R.W. Bailey - Chief Engineer} c. to DA.{Bernard Day - Chassis Design} c. to EFC. RE OIL PUMPS. X.3449. It will be remembered that at one time we had trouble with noisy oil pumps, due to the oil being imprisoned in the teeth at the point where the two gears mesh together. The first measure that proved effective in overcoming the trouble was the use of a small recess at each end of the pump opposite the point of meshing the teeth, and running back a little way into the pressure side of the pump. Mr. Royce afterwards suggested that the pump wheels should be made with teeth of 20° obliquity, and that the teeth should be made a slack fit in each other, and further, that with this alteration, the recesses at the pump ends should be discarded. Would you kindly say if the use of 20° obliquity slack teeth is sufficiently effective in making the pumps quiet without the help of the recesses, as we understand from Mr. Stent that the recess was still a feature of the Eagle pumps made in America. We wish to cancel the recess if it is unnecessary. E.{Mr Elliott - Chief Engineer} | ||