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).
Investigation into different gear train arrangements to achieve a necessary ratio.
| Identifier | ExFiles\Box 15\5\ Scan116 | |
| Date | 12th April 1930 | |
| -2- We have also investigated the following methods of obtaining the necessary ratio :- (1) Simple train annulus driven. (2) Simple train annulus driven driving through the cage of 2nd. speed to annulus of 3rd. speed. (3) Compound train sun driven. (4) Bevel gear. (5) Wilson arrangement. Dealing with these in detail :- (1) SIMPLE TRAIN ANNULUS DRIVEN With a planet speed 1.5 times engine speed this train has a ratio of .650. With 1st. and 2nd. speeds of .290 and .500 3rd. becomes .790. (2) SIMPLE TRAIN ANNULUS DRIVEN DRIVING ANNULUS OF 1st.SPEED With a planet speed 1.1 times engine speed, ratios of .250, .470, and .770 can be obtained. With 1.5 times engine speed 3rd. becomes .740. The ratios in the latter case are practically what we have but the planet speed is high. (3) COMPOUND TRAIN. This willgive our present ratios with a planet speed of 1.15 times engine speed. The pitch velocities are 420 and 800 ft. per min. at 1000 RPM. engine speed, against 250 ft. per min. for 1st. and 2nd. trains when in 3rd.speed. (4) BEVEL GEAR. A .500 reduction bevel gear gives our ratios and has a planet speed of .700 by engine speed, and a pitch velocity of 330 ft. per min. (5) WILSON GEAR. The 3rd. speed train of the Wilson gear does not relieve the other trains of any load, and consequently the tooth loads are higher than with the previous schemes. The tooth load of the 2nd. and 3rd. trains of the Wilson gear are twice those of the gear we are considering. | ||