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).
Difficulties of producing replacement Gleason spiral bevel gears for rear axles.
| Identifier | ExFiles\Box 49\2\ Scan182 | |
| Date | 19th December 1923 | |
| Y3612 DA.{Bernard Day - Chassis Design} c. Hs.{Lord Ernest Hives - Chair} GLEASON SPIRAL BEVEL GEARS FOR REAR AXLES. -------------------- With reference to R3/M.{Mr Moon / Mr Moore} 10. 12. 23. in which it is suggested that we should make pinions in Air Hardening Steel to replace the original fine pitch pinions to be used with the existing crown wheels, although we propose to ask the Works to try this suggestion with a few axles which we may have available, we should certainly be faced with the following difficulties:- 1. The fine pitch gears were produced both by R.R. and E.N.V. Motors, consequently the teeth were cut at slightly different spiral angles. 2. The spiral angles of gears produced both by ourselves and E.N.V. Motors were altered from time to time as we gained experience with them, in order to obtain a better degree of silence. 3. There will be a difficulty in finding out what the spiral angles of the various gears actually are, and it is not easy to ascertain this by measurement. From the foregoing, it will be appreciated that we should have to cut pinions with several spiral angles to suit the existing crown wheels, and we are of the opinion that we should not be able to pair them up to give us the degree of silence which we obtain with the present standard coarse pitch gears, in addition to which the machines would have to be set separately for each different spiral angle, whereas our experience tells us that this is not advisable, and it is better to keep the machines set so as to avoid the necessary adjustments each time, to obtain the bedding etc in the correct position. Tests have proved that whilst originally fine pitch CHNS gears only stood up on the dynamometer for 5 hours 50 minutes, coarse pitch gears made in CHNS. with thickened up pinion teeth, stood up for a period of 50 hours. With reference to R's suggestion to round off the teeth as shown by sketch given in R's memo, certain difficulties would arise in this connection if the teeth were rounded at the large end, because there would be no definite point for the cone distance which is required for setting the gears in the Gleason Contd. | ||