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).
Steering stiffness on the New Phantom chassis, focusing on the design of hardened balls in pivot joints and lubrication methods.
| Identifier | ExFiles\Box 67\3\ scan0307 | |
| Date | 9th October 1925 | |
| 18430 EP.{G. Eric Platford - Chief Quality Engineer} C. HS.{Lord Ernest Hives - Chair} C. MMR. C. WOR.{Arthur Wormald - General Works Manager} C. Wm. BY14/H.{Arthur M. Hanbury - Head Complaints} 9.10.25. NEW PHANTOMCodename for PHANTOM I CHASSIS - STEERING STIFFNESS. Referring to EP{G. Eric Platford - Chief Quality Engineer}8/H.{Arthur M. Hanbury - Head Complaints} 6.10.25. the first point I wish to state is that the addition of grooves in the hardened ball for the steering is a distinct mistake. There is no question but that I was personally responsible for the design idea of the introduction of the grooves, but they were carefully avoided on steering pivot joints and steering balls for the very sufficient reason that these particular bearing surfaces are always being moved fractionally, possibly as a slight dither, without any greater movement being imposed upon them than this for 80% of their life. The result will be that this action will cause keys to form on the bearing surface opposite to the groove. The keys will interlock in what were meant to be oil grooves, and after a short length of time what was in itself a bearing will result in a type of locking apparatus to maintain the steering in one position. In regard to the proposal that we should add a radius to the edge of the sockets, this again has been considered from time to time, but has been side-tracked for two reasons:- a/- It could not possibly affect the issue, as any radius would rapidly revert to the sharp edge effect again. b/- A very material reduction in the area of the ball and pad contact would be made. There is no difference at all in what we are doing to-day from what we have done all along, and personally I cannot believe that the question of the balls alone was responsible for the increased stiffness. An attempt was made by the Works to improve the lubrication by forcing oil through the central hole in the pad, and making a small flat on the ball to prevent the formation of a pip. It was hoped that at least when the grease gun was used, oil would be forced between the surfaces, and a certain amount of lubrication effect might persist as the result of the oil remaining in the space formed by the slight flat on the ball. BY.{R.W. Bailey - Chief Engineer} | ||