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).
Technical memorandum discussing the design and material choices for a propeller shaft universal joint.
| Identifier | ExFiles\Box 15\4\ Scan007 | |
| Date | 25th January 1928 | |
| DA.{Bernard Day - Chassis Design} BY.{R.W. Bailey - Chief Engineer} from R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair} c. to BJ. Wor.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} Y7340 R1/M25.1.28. EAC.10 PROPELLER SHAFT. X.7340 UNIVERSAL JOINTS. X.4183 MECHANIC'S TYPE. My impression is that 5" is too small: we are running with one nearly 7". Had we not better adopt a 6" one? The part that bolts on the flange of the gearbox and bevel pinion can be exactly alike, and must of necessity be the piece that is fitted with the loose pin. This will be a drop forging and not case-hardened. NOTE:- I cannot see any advantage in the taper pin as the Mechanic's ring should hold the large driving pin in - the ends of which might be spherical. (Taper pin bad for production and interchangeability; if anything use a screw as we did for small similar pin on Silver Ghost). The ring and the 4 bearings for the 2 driving pins seem good pieces to make correctly to size if special scheme and tools are provided, and the work of correcting and gauging is carefully organised (after ordinary machining) with the correct amount of draw left when joint faces come together, which ought to be easily ascertained by a few experimental trials. I think that the elasticity of materials will make this satisfactory, and there is no need to depart from the original Mechanic's scheme, which seems the sounder, and if well made will give more robust parts. Now then the difficulty comes in with the next piece. I conclude the pins on this must be case-hardened. As shewn the sliding joint does not seem practical: apparently the teeth of this should also be case-hardened. The sliding joint should be oil-retaining independent of the tightness of the gland, which would not hold oil against the centrifugal force at 3000 revs. The internal serrations should be broachable, and it seems as though we must construct the joint like the sketch. If you could do without brazing in the end, by shrinking, pinning sweating, and taper fit, you could do without the flange, and make a simpler, lighter job with the same advantages. One thinks that with case-hardened parts they could be so much smaller than soft ones. Serration area could be gained by fine pitch or some extra radial depth. If case-hardening is thought unnecessary, then something more simple could be used. FOR SKETCHES SEE ORIGINAL. R.{Sir Henry Royce} | ||