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).
Test report detailing the wear, distortion, and performance of various components including a Bakelite case, bushes, and gears, and concluding on the viability of plastic oil pump casings.
| Identifier | ExFiles\Box 149\2\ scan0203 | |
| Date | 12th April 1939 guessed | |
| -4- However reviewing generally the records of dimensional changes throughout the tests, as shown in Figs. III. A/B/C., the wear on the Bakelite case was negligible, the tendency being for the material to contract. The maximum variation is shown 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 no worse after the final test than after the initial two hours run, in spite of the fact that when cold the driven gear was in contact with the wall of the casing. The BZ/PC bush that supports the driving gear spindle in the casing showed from .001" to .0015" wear on the diameter, and was scored on the thrust face and on the outer edge of the bore, while 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 from .0004" to .0006" diametral wear, and were slightly scored, and although no wear was registered over the face 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 no doubt allowance could be made), and its fragility. Suitable protection from external shocks could of course be provided, but provision against the effects of rapid temperature variation and internal pressure would require more consideration. Cost Analysis of Existing Pump and Moulded Pump :- Existing Casing and Cover :- Part Numbers :- Pump Casing EW.969 ) Section Pump Cover EW.970 ) 5170 Continued......... | ||