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 gearbox noise, bearings, and proposed design changes for clutches and roller bearings.
| Identifier | ExFiles\Box 19\3\ Scan134 | |
| Date | 11th January 1930 guessed | |
| - 4 - This causes excessive noise and has caused complaint, although even under such conditions the boxes have compared favorably with ordinary production gearboxes of standard type. Bearings - The roller bearings are all made by Schubert. In boxes now in cars a pilot bearing is used in the crankshaft and the roller bearing shown at the rear of the pinion shaft is not used. This is conventional unit construction but has caused trouble. Variations in machining of the bell housing have thrown the high speed dog-clutch as much as .003 out of line, causing severe bending loads on pinion shaft, and necessitating a lot of slack in the dogs. Under these conditions there has also been trouble due to gears jumping out of mesh. The new construction shown on the prints takes away the crankshaft pilot bearing entirely, but uses the clutch as a mixed Oldham Coupling and universal joint for any errors in bell-housing alignment. This seems taking a chance but is said to cause no trouble in clutches like the Borg and Beck which have a flexible center to the driven disc. The pinion shaft is well held. A universal drive could be used as on PII. Dog clutches can be made a closer fit with the new construc- tion and rattles should disappear. The rear roller-bearing pilot is peculiar in that the rollers are positioned on the inner race by extensions of the cage, and the cage is made in two halves split across the center with about a .005 gap and not fastened together. Thus each half of the cage rides on the rollers which have to carry the centrifugal force of each half-cage. All the roller cages are of die cast "McGill metal" (hard bronze) made in two halves, a flat plate and a body with cylindrical pockets having integral die cast "rivets" cast on the lands between the pockets. They are very strong and have high bearing qualities. Spool Bearings - These are 7/16" square Hoffmann type rolls on the first spool and 5/16" x 3/8" rolls on the second spool. End thrusts are taken through the bronze cages which are made as above, bearing against surfaces containing eccentric oil grooves. - continued - | ||