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 gear eccentricity, spacing error, and tooth form performance.
| Identifier | ExFiles\Box 94\2\ scan0275 | |
| Date | 9th August 1937 | |
| -2- Gear. Eccentricity. Eccentricity per pair. Spacing error. Tooth Form Remarks From Graphs. Constant Mesh wheel .002 .0025 .00024 Moderately good - slight tip relief. Constant Mesh Pinion. .0017 .0004 Profile under-cut below pitch line. 3rd. Speed Driving. .0006 .0015 .00036 Poor, excessive relief above & below pitch line. May be due to lapping of tooth form. 3rd. Speed Driven. .001 .00028 Under-cut below pitch line - irregular profile. Gear Pair. Eccentricity per pair. Red Line Graph analysis. 2nd. Speeds. .002 Slight pressure angle differences are shown. 1st. Speeds. .002 Unevenness of tooth spacing and variation of pressure angle in rating tooth forms. 1st. Speed Driven & Reverse Shaft. .001 Unevenness of spacing and excessive variation of pressure angle in mating tooth forms. The eccentricity obtained when the gears were mated up, was measured as variation of centre distance when the pairs were close in mesh. As a comparison to our ground gears the figures obtained are not excessive as .0015 to .002 is commonly obtained, but preference for not in excess of .001 is desired. Spacing errors are large in the gears measured and should not exceed .0002, which is the maximum allowed by our standards. Continued..... | ||