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).
Analysis of wear on gear components and a conclusion on the viability of plastic oil pump casings.
| Identifier | ExFiles\Box 149\2\ scan0188 | |
| Date | 31th March 1939 | |
| -2- HPS{Horace Percy Smith - Experimental Factory Mgr}/B1.1/CB.31.3.39. to be .0018" over the length of the gear well and this is considered to be due to distortion. The "scruffing" of the walls was not any worse after the final run than after the first 2 hour period - probably due to expansion at temperature - in spite of the fact that when cold, the driven gear was in contact with the wall of the casing. The thrust plate showed only localized bedding - due to buckling - and in the extreme, only .002" wear was registered. Considering the BZ/PC bushes, that supporting the driving gear spindle in the main casing registered .001" to .0015" wear on the diameter and was scored on the thrust face and on the outer edge of the bore, whilst the corresponding bush in the cover was .003" oval - due to pressure loading. The driven gear bush had increased .0007" in diameter and there were practically no score marks in its bore. The spindle was also in good condition, showing a maximum wear of .0005" on diameter. The driving gear spindles showed .0004" to .0006" diametral wear, and were slightly scored and whilst no wear was registered over the length of the gear, the thrust face was scored. Other than being polished on the contact surfaces, the teeth were unmarked. The driving serrations were badly worn. The driven gear showed only .0006" end wear and was slightly scored on the thrust face - incidentally, the bedding on the teeth of this gear was poor. _____ In conclusion, whilst the production of oil pump casings in plastic materials has possibilities, the chief objections from the evidence of these tests are the tendency to "grow" (for which allowance could, no doubt, be made) and its fragility. Suitable protection from external shocks and vibrations could, of course, be provided but provision against the effects of rapid temperature variation and internal pressure would require more consideration. HPS{Horace Percy Smith - Experimental Factory Mgr}/W.Bell. | ||